Internet DRAFT - draft-ietf-ippm-initial-registry
draft-ietf-ippm-initial-registry
Network Working Group A. Morton
Internet-Draft AT&T Labs
Intended status: Standards Track M. Bagnulo
Expires: September 10, 2020 UC3M
P. Eardley
BT
K. D'Souza
AT&T Labs
March 9, 2020
Initial Performance Metrics Registry Entries
draft-ietf-ippm-initial-registry-16
Abstract
This memo defines the set of Initial Entries for the IANA Performance
Metrics Registry. The set includes: UDP Round-trip Latency and Loss,
Packet Delay Variation, DNS Response Latency and Loss, UDP Poisson
One-way Delay and Loss, UDP Periodic One-way Delay and Loss, ICMP
Round-trip Latency and Loss, and TCP round-trip Latency and Loss.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14[RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 10, 2020.
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Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 6
2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Registry Categories and Columns . . . . . . . . . . . . . . . 7
4. UDP Round-trip Latency and Loss Registry Entries . . . . . . 8
4.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.1. ID (Identifier) . . . . . . . . . . . . . . . . . . . 9
4.1.2. Name . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.3. URI . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.4. Description . . . . . . . . . . . . . . . . . . . . . 9
4.1.5. Change Controller . . . . . . . . . . . . . . . . . . 9
4.1.6. Version (of Registry Format) . . . . . . . . . . . . 9
4.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 10
4.2.1. Reference Definition . . . . . . . . . . . . . . . . 10
4.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 10
4.3. Method of Measurement . . . . . . . . . . . . . . . . . . 11
4.3.1. Reference Method . . . . . . . . . . . . . . . . . . 11
4.3.2. Packet Stream Generation . . . . . . . . . . . . . . 12
4.3.3. Traffic Filtering (observation) Details . . . . . . . 13
4.3.4. Sampling Distribution . . . . . . . . . . . . . . . . 13
4.3.5. Run-time Parameters and Data Format . . . . . . . . . 13
4.3.6. Roles . . . . . . . . . . . . . . . . . . . . . . . . 14
4.4. Output . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.4.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 14
4.4.2. Reference Definition . . . . . . . . . . . . . . . . 14
4.4.3. Metric Units . . . . . . . . . . . . . . . . . . . . 15
4.4.4. Calibration . . . . . . . . . . . . . . . . . . . . . 15
4.5. Administrative items . . . . . . . . . . . . . . . . . . 16
4.5.1. Status . . . . . . . . . . . . . . . . . . . . . . . 16
4.5.2. Requester . . . . . . . . . . . . . . . . . . . . . . 16
4.5.3. Revision . . . . . . . . . . . . . . . . . . . . . . 16
4.5.4. Revision Date . . . . . . . . . . . . . . . . . . . . 16
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4.6. Comments and Remarks . . . . . . . . . . . . . . . . . . 16
5. Packet Delay Variation Registry Entry . . . . . . . . . . . . 16
5.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1.1. ID (Identifier) . . . . . . . . . . . . . . . . . . . 16
5.1.2. Name . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1.3. URI . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1.4. Description . . . . . . . . . . . . . . . . . . . . . 17
5.1.5. Change Controller . . . . . . . . . . . . . . . . . . 17
5.1.6. Version (of Registry Format) . . . . . . . . . . . . 17
5.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 17
5.2.1. Reference Definition . . . . . . . . . . . . . . . . 17
5.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 18
5.3. Method of Measurement . . . . . . . . . . . . . . . . . . 19
5.3.1. Reference Method . . . . . . . . . . . . . . . . . . 19
5.3.2. Packet Stream Generation . . . . . . . . . . . . . . 19
5.3.3. Traffic Filtering (observation) Details . . . . . . . 20
5.3.4. Sampling Distribution . . . . . . . . . . . . . . . . 20
5.3.5. Run-time Parameters and Data Format . . . . . . . . . 20
5.3.6. Roles . . . . . . . . . . . . . . . . . . . . . . . . 21
5.4. Output . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.4.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 21
5.4.2. Reference Definition . . . . . . . . . . . . . . . . 21
5.4.3. Metric Units . . . . . . . . . . . . . . . . . . . . 22
5.4.4. Calibration . . . . . . . . . . . . . . . . . . . . . 22
5.5. Administrative items . . . . . . . . . . . . . . . . . . 23
5.5.1. Status . . . . . . . . . . . . . . . . . . . . . . . 23
5.5.2. Requester . . . . . . . . . . . . . . . . . . . . . . 23
5.5.3. Revision . . . . . . . . . . . . . . . . . . . . . . 23
5.5.4. Revision Date . . . . . . . . . . . . . . . . . . . . 23
5.6. Comments and Remarks . . . . . . . . . . . . . . . . . . 23
6. DNS Response Latency and Loss Registry Entries . . . . . . . 23
6.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.1.1. ID (Identifier) . . . . . . . . . . . . . . . . . . . 24
6.1.2. Name . . . . . . . . . . . . . . . . . . . . . . . . 24
6.1.3. URI . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.1.4. Description . . . . . . . . . . . . . . . . . . . . . 24
6.1.5. Change Controller . . . . . . . . . . . . . . . . . . 24
6.1.6. Version (of Registry Format) . . . . . . . . . . . . 24
6.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 24
6.2.1. Reference Definition . . . . . . . . . . . . . . . . 24
6.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 25
6.3. Method of Measurement . . . . . . . . . . . . . . . . . . 27
6.3.1. Reference Method . . . . . . . . . . . . . . . . . . 27
6.3.2. Packet Stream Generation . . . . . . . . . . . . . . 28
6.3.3. Traffic Filtering (observation) Details . . . . . . . 29
6.3.4. Sampling Distribution . . . . . . . . . . . . . . . . 29
6.3.5. Run-time Parameters and Data Format . . . . . . . . . 29
6.3.6. Roles . . . . . . . . . . . . . . . . . . . . . . . . 30
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6.4. Output . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.4.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 30
6.4.2. Reference Definition . . . . . . . . . . . . . . . . 31
6.4.3. Metric Units . . . . . . . . . . . . . . . . . . . . 31
6.4.4. Calibration . . . . . . . . . . . . . . . . . . . . . 31
6.5. Administrative items . . . . . . . . . . . . . . . . . . 32
6.5.1. Status . . . . . . . . . . . . . . . . . . . . . . . 32
6.5.2. Requester . . . . . . . . . . . . . . . . . . . . . . 32
6.5.3. Revision . . . . . . . . . . . . . . . . . . . . . . 32
6.5.4. Revision Date . . . . . . . . . . . . . . . . . . . . 32
6.6. Comments and Remarks . . . . . . . . . . . . . . . . . . 32
7. UDP Poisson One-way Delay and Loss Registry Entries . . . . . 32
7.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.1.1. ID (Identifier) . . . . . . . . . . . . . . . . . . . 33
7.1.2. Name . . . . . . . . . . . . . . . . . . . . . . . . 33
7.1.3. URI . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.1.4. Description . . . . . . . . . . . . . . . . . . . . . 33
7.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 34
7.2.1. Reference Definition . . . . . . . . . . . . . . . . 34
7.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 35
7.3. Method of Measurement . . . . . . . . . . . . . . . . . . 36
7.3.1. Reference Method . . . . . . . . . . . . . . . . . . 36
7.3.2. Packet Stream Generation . . . . . . . . . . . . . . 36
7.3.3. Traffic Filtering (observation) Details . . . . . . . 37
7.3.4. Sampling Distribution . . . . . . . . . . . . . . . . 37
7.3.5. Run-time Parameters and Data Format . . . . . . . . . 37
7.3.6. Roles . . . . . . . . . . . . . . . . . . . . . . . . 38
7.4. Output . . . . . . . . . . . . . . . . . . . . . . . . . 38
7.4.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 38
7.4.2. Reference Definition . . . . . . . . . . . . . . . . 38
7.4.3. Metric Units . . . . . . . . . . . . . . . . . . . . 41
7.4.4. Calibration . . . . . . . . . . . . . . . . . . . . . 41
7.5. Administrative items . . . . . . . . . . . . . . . . . . 42
7.5.1. Status . . . . . . . . . . . . . . . . . . . . . . . 42
7.5.2. Requester . . . . . . . . . . . . . . . . . . . . . . 42
7.5.3. Revision . . . . . . . . . . . . . . . . . . . . . . 42
7.5.4. Revision Date . . . . . . . . . . . . . . . . . . . . 43
7.6. Comments and Remarks . . . . . . . . . . . . . . . . . . 43
8. UDP Periodic One-way Delay and Loss Registry Entries . . . . 43
8.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 43
8.1.1. ID (Identifier) . . . . . . . . . . . . . . . . . . . 43
8.1.2. Name . . . . . . . . . . . . . . . . . . . . . . . . 43
8.1.3. URI . . . . . . . . . . . . . . . . . . . . . . . . . 44
8.1.4. Description . . . . . . . . . . . . . . . . . . . . . 44
8.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 44
8.2.1. Reference Definition . . . . . . . . . . . . . . . . 44
8.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 45
8.3. Method of Measurement . . . . . . . . . . . . . . . . . . 46
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8.3.1. Reference Method . . . . . . . . . . . . . . . . . . 46
8.3.2. Packet Stream Generation . . . . . . . . . . . . . . 47
8.3.3. Traffic Filtering (observation) Details . . . . . . . 48
8.3.4. Sampling Distribution . . . . . . . . . . . . . . . . 48
8.3.5. Run-time Parameters and Data Format . . . . . . . . . 48
8.3.6. Roles . . . . . . . . . . . . . . . . . . . . . . . . 48
8.4. Output . . . . . . . . . . . . . . . . . . . . . . . . . 49
8.4.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 49
8.4.2. Reference Definition . . . . . . . . . . . . . . . . 49
8.4.3. Metric Units . . . . . . . . . . . . . . . . . . . . 52
8.4.4. Calibration . . . . . . . . . . . . . . . . . . . . . 52
8.5. Administrative items . . . . . . . . . . . . . . . . . . 53
8.5.1. Status . . . . . . . . . . . . . . . . . . . . . . . 53
8.5.2. Requester . . . . . . . . . . . . . . . . . . . . . . 53
8.5.3. Revision . . . . . . . . . . . . . . . . . . . . . . 53
8.5.4. Revision Date . . . . . . . . . . . . . . . . . . . . 53
8.6. Comments and Remarks . . . . . . . . . . . . . . . . . . 54
9. ICMP Round-trip Latency and Loss Registry Entries . . . . . . 54
9.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 54
9.1.1. ID (Identifier) . . . . . . . . . . . . . . . . . . . 54
9.1.2. Name . . . . . . . . . . . . . . . . . . . . . . . . 54
9.1.3. URI . . . . . . . . . . . . . . . . . . . . . . . . . 54
9.1.4. Description . . . . . . . . . . . . . . . . . . . . . 55
9.1.5. Change Controller . . . . . . . . . . . . . . . . . . 55
9.1.6. Version (of Registry Format) . . . . . . . . . . . . 55
9.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 55
9.2.1. Reference Definition . . . . . . . . . . . . . . . . 55
9.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 56
9.3. Method of Measurement . . . . . . . . . . . . . . . . . . 57
9.3.1. Reference Method . . . . . . . . . . . . . . . . . . 57
9.3.2. Packet Stream Generation . . . . . . . . . . . . . . 58
9.3.3. Traffic Filtering (observation) Details . . . . . . . 59
9.3.4. Sampling Distribution . . . . . . . . . . . . . . . . 59
9.3.5. Run-time Parameters and Data Format . . . . . . . . . 59
9.3.6. Roles . . . . . . . . . . . . . . . . . . . . . . . . 59
9.4. Output . . . . . . . . . . . . . . . . . . . . . . . . . 60
9.4.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 60
9.4.2. Reference Definition . . . . . . . . . . . . . . . . 60
9.4.3. Metric Units . . . . . . . . . . . . . . . . . . . . 62
9.4.4. Calibration . . . . . . . . . . . . . . . . . . . . . 62
9.5. Administrative items . . . . . . . . . . . . . . . . . . 62
9.5.1. Status . . . . . . . . . . . . . . . . . . . . . . . 62
9.5.2. Requester . . . . . . . . . . . . . . . . . . . . . . 63
9.5.3. Revision . . . . . . . . . . . . . . . . . . . . . . 63
9.5.4. Revision Date . . . . . . . . . . . . . . . . . . . . 63
9.6. Comments and Remarks . . . . . . . . . . . . . . . . . . 63
10. TCP Round-Trip Delay and Loss Registry Entries . . . . . . . 63
10.1. Summary . . . . . . . . . . . . . . . . . . . . . . . . 63
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10.1.1. ID (Identifier) . . . . . . . . . . . . . . . . . . 63
10.1.2. Name . . . . . . . . . . . . . . . . . . . . . . . . 63
10.1.3. URI . . . . . . . . . . . . . . . . . . . . . . . . 64
10.1.4. Description . . . . . . . . . . . . . . . . . . . . 64
10.1.5. Change Controller . . . . . . . . . . . . . . . . . 64
10.1.6. Version (of Registry Format) . . . . . . . . . . . . 64
10.2. Metric Definition . . . . . . . . . . . . . . . . . . . 65
10.2.1. Reference Definitions . . . . . . . . . . . . . . . 65
10.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 67
10.3. Method of Measurement . . . . . . . . . . . . . . . . . 68
10.3.1. Reference Methods . . . . . . . . . . . . . . . . . 68
10.3.2. Packet Stream Generation . . . . . . . . . . . . . . 70
10.3.3. Traffic Filtering (observation) Details . . . . . . 70
10.3.4. Sampling Distribution . . . . . . . . . . . . . . . 70
10.3.5. Run-time Parameters and Data Format . . . . . . . . 70
10.3.6. Roles . . . . . . . . . . . . . . . . . . . . . . . 71
10.4. Output . . . . . . . . . . . . . . . . . . . . . . . . . 71
10.4.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 71
10.4.2. Reference Definition . . . . . . . . . . . . . . . . 71
10.4.3. Metric Units . . . . . . . . . . . . . . . . . . . . 73
10.4.4. Calibration . . . . . . . . . . . . . . . . . . . . 73
10.5. Administrative items . . . . . . . . . . . . . . . . . . 73
10.5.1. Status . . . . . . . . . . . . . . . . . . . . . . . 73
10.5.2. Requester . . . . . . . . . . . . . . . . . . . . . 73
10.5.3. Revision . . . . . . . . . . . . . . . . . . . . . . 74
10.5.4. Revision Date . . . . . . . . . . . . . . . . . . . 74
10.6. Comments and Remarks . . . . . . . . . . . . . . . . . . 74
11. Security Considerations . . . . . . . . . . . . . . . . . . . 74
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 74
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 74
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 75
14.1. Normative References . . . . . . . . . . . . . . . . . . 75
14.2. Informative References . . . . . . . . . . . . . . . . . 77
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 78
1. Introduction
This memo proposes an initial set of entries for the Performance
Metrics Registry. It uses terms and definitions from the IPPM
literature, primarily [RFC2330].
Although there are several standard templates for organizing
specifications of performance metrics (see [RFC7679] for an example
of the traditional IPPM template, based to large extent on the
Benchmarking Methodology Working Group's traditional template in
[RFC1242], and see [RFC6390] for a similar template), none of these
templates were intended to become the basis for the columns of an
IETF-wide registry of metrics. While examining aspects of metric
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specifications which need to be registered, it became clear that none
of the existing metric templates fully satisfies the particular needs
of a registry.
Therefore, [I-D.ietf-ippm-metric-registry] defines the overall format
for a Performance Metrics Registry. Section 5 of
[I-D.ietf-ippm-metric-registry] also gives guidelines for those
requesting registration of a Metric, that is the creation of entry(s)
in the Performance Metrics Registry: "In essence, there needs to be
evidence that a candidate Registered Performance Metric has
significant industry interest, or has seen deployment, and there is
agreement that the candidate Registered Performance Metric serves its
intended purpose." The process in [I-D.ietf-ippm-metric-registry]
also requires that new entries are administered by IANA through
Specification Required policy, which will ensure that the metrics are
tightly defined.
2. Scope
This document defines a set of initial Performance Metrics Registry
entries. Most are Active Performance Metrics, which are based on
RFCs prepared in the IPPM working group of the IETF, according to
their framework [RFC2330] and its updates.
3. Registry Categories and Columns
This memo uses the terminology defined in
[I-D.ietf-ippm-metric-registry].
This section provides the categories and columns of the registry, for
easy reference. An entry (row) therefore gives a complete
description of a Registered Metric.
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Legend:
Registry Categories and Columns, shown as
Category
------------------
Column | Column |
Summary
------------------------------------------------------------------------
Identifier | Name | URI | Desc. | Reference | Change Controller | Ver |
Metric Definition
-----------------------------------------
Reference Definition | Fixed Parameters |
Method of Measurement
---------------------------------------------------------------------
Reference | Packet | Traffic | Sampling | Run-time | Role |
Method | Stream | Filter | Distribution | Parameters | |
| Generation |
Output
-----------------------------------------
Type | Reference | Units | Calibration |
| Definition | | |
Administrative Information
------------------------------------
Status |Requester | Rev | Rev.Date |
Comments and Remarks
--------------------
4. UDP Round-trip Latency and Loss Registry Entries
This section specifies an initial registry entry for the UDP Round-
trip Latency, and another entry for UDP Round-trip Loss Ratio.
Note: Each Registry entry only produces a "raw" output or a
statistical summary. To describe both "raw" and one or more
statistics efficiently, the Identifier, Name, and Output Categories
can be split and a single section can specify two or more closely-
related metrics. For example, this section specifies two Registry
entries with many common columns. See Section 7 for an example
specifying multiple Registry entries with many common columns.
All column entries beside the ID, Name, Description, and Output
Reference Method categories are the same, thus this section proposes
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two closely-related registry entries. As a result, IANA is also
asked to assign a corresponding URL to each Named Metric.
4.1. Summary
This category includes multiple indexes to the registry entry: the
element ID and metric name.
4.1.1. ID (Identifier)
IANA is asked to assign different numeric identifiers to each of the
two Named Metrics.
4.1.2. Name
RTDelay_Active_IP-UDP-Periodic_RFCXXXXsec4_Seconds_95Percentile
RTLoss_Active_IP-UDP-Periodic_RFCXXXXsec4_Percent_LossRatio
4.1.3. URI
URL: https://www.iana.org/ ... <name>
4.1.4. Description
RTDelay: This metric assesses the delay of a stream of packets
exchanged between two hosts (which are the two measurement points),
and the Output is the Round-trip delay for all successfully exchanged
packets expressed as the 95th percentile of their conditional delay
distribution.
RTLoss: This metric assesses the loss ratio of a stream of packets
exchanged between two hosts (which are the two measurement points),
and the Output is the Round-trip loss ratio for all successfully
exchanged packets expressed as a percentage.
4.1.5. Change Controller
IETF
4.1.6. Version (of Registry Format)
1.0
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4.2. Metric Definition
This category includes columns to prompt the entry of all necessary
details related to the metric definition, including the RFC reference
and values of input factors, called fixed parameters.
4.2.1. Reference Definition
Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip Delay
Metric for IPPM", RFC 2681, September 1999.
[RFC2681]
Section 2.4 of [RFC2681] provides the reference definition of the
singleton (single value) Round-trip delay metric. Section 3.4 of
[RFC2681] provides the reference definition expanded to cover a
multi-singleton sample. Note that terms such as singleton and sample
are defined in Section 11 of [RFC2330].
Note that although the [RFC2681] definition of "Round-trip-Delay
between Src and Dst" is directionally ambiguous in the text, this
metric tightens the definition further to recognize that the host in
the "Src" role will send the first packet to "Dst", and ultimately
receive the corresponding return packet from "Dst" (when neither are
lost).
Finally, note that the variable "dT" is used in [RFC2681] to refer to
the value of Round-trip delay in metric definitions and methods. The
variable "dT" has been re-used in other IPPM literature to refer to
different quantities, and cannot be used as a global variable name.
Morton, A., "Round-trip Packet Loss Metrics", RFC 6673, August 2012.
[RFC6673]
Both delay and loss metrics employ a maximum waiting time for
received packets, so the count of lost packets to total packets sent
is the basis for the loss ratio calculation as per Section 6.1 of
[RFC6673].
4.2.2. Fixed Parameters
Type-P as defined in Section 13 of [RFC2330]:
o IPv4 header values:
* DSCP: set to 0
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* TTL: set to 255
* Protocol: set to 17 (UDP)
o IPv6 header values:
* DSCP: set to 0
* Hop Count: set to 255
* Next Header: set to 17 (UDP)
* Flow Label: set to zero
* Extension Headers: none
o UDP header values:
* Checksum: the checksum MUST be calculated and the non-zero
checksum included in the header
o UDP Payload
* total of 100 bytes
Other measurement parameters:
o Tmax: a loss threshold waiting time
* 3.0, expressed in units of seconds, as a positive value of type
decimal64 with fraction digits = 4 (see section 9.3 of
[RFC6020]) and with resolution of 0.0001 seconds (0.1 ms), with
lossless conversion to/from the 32-bit NTP timestamp as per
section 6 of [RFC5905].
4.3. Method of Measurement
This category includes columns for references to relevant sections of
the RFC(s) and any supplemental information needed to ensure an
unambiguous methods for implementations.
4.3.1. Reference Method
The methodology for this metric is defined as Type-P-Round-trip-
Delay-Poisson-Stream in section 2.6 of RFC 2681 [RFC2681] and section
3.6 of RFC 2681 [RFC2681] using the Type-P and Tmax defined under
Fixed Parameters. However, the Periodic stream will be generated
according to [RFC3432].
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The reference method distinguishes between long-delayed packets and
lost packets by implementing a maximum waiting time for packet
arrival. Tmax is the waiting time used as the threshold to declare a
packet lost. Lost packets SHALL be designated as having undefined
delay, and counted for the RTLoss metric.
The calculations on the delay (RTT) SHALL be performed on the
conditional distribution, conditioned on successful packet arrival
within Tmax. Also, when all packet delays are stored, the process
which calculates the RTT value MUST enforce the Tmax threshold on
stored values before calculations. See section 4.1 of [RFC3393] for
details on the conditional distribution to exclude undefined values
of delay, and Section 5 of [RFC6703] for background on this analysis
choice.
The reference method requires some way to distinguish between
different packets in a stream to establish correspondence between
sending times and receiving times for each successfully-arriving
packet. Sequence numbers or other send-order identification MUST be
retained at the Src or included with each packet to disambiguate
packet reordering if it occurs.
If a standard measurement protocol is employed, then the measurement
process will determine the sequence numbers or timestamps applied to
test packets after the Fixed and Runtime parameters are passed to
that process. The chosen measurement protocol will dictate the
format of sequence numbers and time-stamps, if they are conveyed in
the packet payload.
Refer to Section 4.4 of [RFC6673] for expanded discussion of the
instruction to "send a Type-P packet back to the Src as quickly as
possible" in Section 2.6 of RFC 2681 [RFC2681]. Section 8 of
[RFC6673] presents additional requirements which MUST be included in
the method of measurement for this metric.
4.3.2. Packet Stream Generation
This section gives the details of the packet traffic which is the
basis for measurement. In IPPM metrics, this is called the Stream,
and can easily be described by providing the list of stream
parameters.
Section 3 of [RFC3432] prescribes the method for generating Periodic
streams using associated parameters.
incT the nominal duration of inter-packet interval, first bit to
first bit, with value 0.0200, expressed in units of seconds, as a
positive value of type decimal64 with fraction digits = 4 (see
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section 9.3 of [RFC6020]) and with resolution of 0.0001 seconds
(0.1 ms).
dT the duration of the interval for allowed sample start times, with
value 1.0, expressed in units of seconds, as a positive value of
type decimal64 with fraction digits = 4 (see section 9.3 of
[RFC6020]) and with resolution of 0.0001 seconds (0.1 ms).
NOTE: an initiation process with a number of control exchanges
resulting in unpredictable start times (within a time interval) may
be sufficient to avoid synchronization of periodic streams, and
therefore a valid replacement for selecting a start time at random
from a fixed interval.
The T0 parameter will be reported as a measured parameter.
Parameters incT and dT are Fixed Parameters.
4.3.3. Traffic Filtering (observation) Details
NA
4.3.4. Sampling Distribution
NA
4.3.5. Run-time Parameters and Data Format
Run-time Parameters are input factors that must be determined,
configured into the measurement system, and reported with the results
for the context to be complete.
Src the IP address of the host in the Src Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see Section 4 of [RFC6991])
Dst the IP address of the host in the Dst Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see section 4 of [RFC6991])
T0 a time, the start of a measurement interval, (format "date-and-
time" as specified in Section 5.6 of [RFC3339], see also Section 3
of [RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a start time is unspecified
and Tf is to be interpreted as the Duration of the measurement
interval. The start time is controlled through other means.
Tf a time, the end of a measurement interval, (format "date-and-time"
as specified in Section 5.6 of [RFC3339], see also Section 3 of
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[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a end time date is ignored and
Tf is interpreted as the Duration of the measurement interval.
4.3.6. Roles
Src launches each packet and waits for return transmissions from
Dst.
Dst waits for each packet from Src and sends a return packet to Src.
4.4. Output
This category specifies all details of the Output of measurements
using the metric.
4.4.1. Type
Percentile -- for the conditional distribution of all packets with a
valid value of Round-trip delay (undefined delays are excluded), a
single value corresponding to the 95th percentile, as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
The percentile = 95, meaning that the reported delay, "95Percentile",
is the smallest value of Round-trip delay for which the Empirical
Distribution Function (EDF), F(95Percentile) >= 95% of the singleton
Round-trip delay values in the conditional distribution. See section
11.3 of [RFC2330] for the definition of the percentile statistic
using the EDF.
LossRatio -- the count of lost packets to total packets sent is the
basis for the loss ratio calculation as per Section 6.1 of [RFC6673].
4.4.2. Reference Definition
For all outputs ---
T0 the start of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
Tf the end of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
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[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
TotalPkts the count of packets sent by the Src to Dst during the
measurement interval.
For
RTDelay_Active_IP-UDP-Periodic_RFCXXXXsec4_Seconds_95Percentile:
95Percentile The time value of the result is expressed in units of
seconds, as a positive value of type decimal64 with fraction
digits = 9 (see section 9.3 of [RFC6020]) with resolution of
0.000000001 seconds (1.0 ns).
For
RTLoss_Active_IP-UDP-Periodic_RFCXXXXsec4_Percent_LossRatio:
Percentile The numeric value of the result is expressed in units of
lost packets to total packets times 100%, as a positive value of
type decimal64 with fraction digits = 9 (see section 9.3 of
[RFC6020]) with resolution of 0.0000000001.
4.4.3. Metric Units
The 95th Percentile of Round-trip Delay is expressed in seconds.
The Round-trip Loss Ratio is expressed as a percentage of lost
packets to total packets sent.
4.4.4. Calibration
Section 3.7.3 of [RFC7679] provides a means to quantify the
systematic and random errors of a time measurement. In-situ
calibration could be enabled with an internal loopback at the Source
host that includes as much of the measurement system as possible,
performs address manipulation as needed, and provides some form of
isolation (e.g., deterministic delay) to avoid send-receive interface
contention. Some portion of the random and systematic error can be
characterized this way.
When a measurement controller requests a calibration measurement, the
loopback is applied and the result is output in the same format as a
normal measurement with additional indication that it is a
calibration result.
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Both internal loopback calibration and clock synchronization can be
used to estimate the available accuracy of the Output Metric Units.
For example, repeated loopback delay measurements will reveal the
portion of the Output result resolution which is the result of system
noise, and thus inaccurate.
4.5. Administrative items
4.5.1. Status
Current
4.5.2. Requester
This RFC number
4.5.3. Revision
1.0
4.5.4. Revision Date
YYYY-MM-DD
4.6. Comments and Remarks
None.
5. Packet Delay Variation Registry Entry
This section gives an initial registry entry for a Packet Delay
Variation metric.
5.1. Summary
This category includes multiple indexes to the registry entries, the
element ID and metric name.
5.1.1. ID (Identifier)
<insert numeric identifier, an integer>
5.1.2. Name
OWPDV_Active_IP-UDP-Periodic_RFCXXXXsec5_Seconds_95Percentile
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5.1.3. URI
URL: https://www.iana.org/ ... <name>
5.1.4. Description
An assessment of packet delay variation with respect to the minimum
delay observed on the periodic stream, and the Output is expressed as
the 95th percentile of the packet delay variation distribution.
5.1.5. Change Controller
IETF
5.1.6. Version (of Registry Format)
1.0
5.2. Metric Definition
This category includes columns to prompt the entry of all necessary
details related to the metric definition, including the RFC reference
and values of input factors, called fixed parameters.
5.2.1. Reference Definition
Paxson, V., Almes, G., Mahdavi, J., and M. Mathis, "Framework for IP
Performance Metrics", RFC 2330, May 1998. [RFC2330]
Demichelis, C. and P. Chimento, "IP Packet Delay Variation Metric
for IP Performance Metrics (IPPM)", RFC 3393, November 2002.
[RFC3393]
Morton, A. and B. Claise, "Packet Delay Variation Applicability
Statement", RFC 5481, March 2009. [RFC5481]
Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network Time
Protocol Version 4: Protocol and Algorithms Specification", RFC 5905,
June 2010. [RFC5905]
See sections 2.4 and 3.4 of [RFC3393]. Singleton delay differences
measured are referred to by the variable name "ddT" (applicable to
all forms of delay variation). However, this metric entry specifies
the PDV form defined in section 4.2 of [RFC5481], where the singleton
PDV for packet i is referred to by the variable name "PDV(i)".
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5.2.2. Fixed Parameters
o IPv4 header values:
* DSCP: set to 0
* TTL: set to 255
* Protocol: set to 17 (UDP)
o IPv6 header values:
* DSCP: set to 0
* Hop Count: set to 255
* Next Header: set to 17 (UDP)
* Flow Label: set to zero
* Extension Headers: none
o UDP header values:
* Checksum: the checksum MUST be calculated and the non-zero
checksum included in the header
o UDP Payload
* total of 200 bytes
Other measurement parameters:
Tmax: a loss threshold waiting time with value 3.0, expressed in
units of seconds, as a positive value of type decimal64 with
fraction digits = 4 (see section 9.3 of [RFC6020]) and with
resolution of 0.0001 seconds (0.1 ms), with lossless conversion
to/from the 32-bit NTP timestamp as per section 6 of [RFC5905].
F a selection function unambiguously defining the packets from the
stream selected for the metric. See section 4.2 of [RFC5481] for
the PDV form.
See the Packet Stream generation category for two additional Fixed
Parameters.
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5.3. Method of Measurement
This category includes columns for references to relevant sections of
the RFC(s) and any supplemental information needed to ensure an
unambiguous methods for implementations.
5.3.1. Reference Method
See section 2.6 and 3.6 of [RFC3393] for general singleton element
calculations. This metric entry requires implementation of the PDV
form defined in section 4.2 of [RFC5481]. Also see measurement
considerations in section 8 of [RFC5481].
The reference method distinguishes between long-delayed packets and
lost packets by implementing a maximum waiting time for packet
arrival. Tmax is the waiting time used as the threshold to declare a
packet lost. Lost packets SHALL be designated as having undefined
delay.
The calculations on the one-way delay SHALL be performed on the
conditional distribution, conditioned on successful packet arrival
within Tmax. Also, when all packet delays are stored, the process
which calculates the one-way delay value MUST enforce the Tmax
threshold on stored values before calculations. See section 4.1 of
[RFC3393] for details on the conditional distribution to exclude
undefined values of delay, and Section 5 of [RFC6703] for background
on this analysis choice.
The reference method requires some way to distinguish between
different packets in a stream to establish correspondence between
sending times and receiving times for each successfully-arriving
packet. Sequence numbers or other send-order identification MUST be
retained at the Src or included with each packet to disambiguate
packet reordering if it occurs.
If a standard measurement protocol is employed, then the measurement
process will determine the sequence numbers or timestamps applied to
test packets after the Fixed and Runtime parameters are passed to
that process. The chosen measurement protocol will dictate the
format of sequence numbers and time-stamps, if they are conveyed in
the packet payload.
5.3.2. Packet Stream Generation
This section gives the details of the packet traffic which is the
basis for measurement. In IPPM metrics, this is called the Stream,
and can easily be described by providing the list of stream
parameters.
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Section 3 of [RFC3432] prescribes the method for generating Periodic
streams using associated parameters.
incT the nominal duration of inter-packet interval, first bit to
first bit, with value 0.0200, expressed in units of seconds, as a
positive value of type decimal64 with fraction digits = 4 (see
section 9.3 of [RFC6020]) and with resolution of 0.0001 seconds
(0.1 ms).
dT the duration of the interval for allowed sample start times, with
value 1.0, expressed in units of seconds, as a positive value of
type decimal64 with fraction digits = 4 (see section 9.3 of
[RFC6020]) and with resolution of 0.0001 seconds (0.1 ms).
NOTE: an initiation process with a number of control exchanges
resulting in unpredictable start times (within a time interval) may
be sufficient to avoid synchronization of periodic streams, and
therefore a valid replacement for selecting a start time at random
from a fixed interval.
The T0 parameter will be reported as a measured parameter.
Parameters incT and dT are Fixed Parameters.
5.3.3. Traffic Filtering (observation) Details
NA
5.3.4. Sampling Distribution
NA
5.3.5. Run-time Parameters and Data Format
Src the IP address of the host in the Src Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see Section 4 of [RFC6991])
Dst the IP address of the host in the Dst Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see section 4 of [RFC6991])
T0 a time, the start of a measurement interval, (format "date-and-
time" as specified in Section 5.6 of [RFC3339], see also Section 3
of [RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a start time is unspecified
and Tf is to be interpreted as the Duration of the measurement
interval. The start time is controlled through other means.
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Tf a time, the end of a measurement interval, (format "date-and-time"
as specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a end time date is ignored and
Tf is interpreted as the Duration of the measurement interval.
5.3.6. Roles
Src launches each packet and waits for return transmissions from
Dst.
Dst waits for each packet from Src and sends a return packet to Src.
5.4. Output
This category specifies all details of the Output of measurements
using the metric.
5.4.1. Type
Percentile -- for the conditional distribution of all packets with a
valid value of one-way delay (undefined delays are excluded), a
single value corresponding to the 95th percentile, as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
The percentile = 95, meaning that the reported delay, "95Percentile",
is the smallest value of one-way PDV for which the Empirical
Distribution Function (EDF), F(95Percentile) >= 95% of the singleton
one-way PDV values in the conditional distribution. See section 11.3
of [RFC2330] for the definition of the percentile statistic using the
EDF.
5.4.2. Reference Definition
T0 the start of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
Tf the end of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
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95Percentile The time value of the result is expressed in units of
seconds, as a positive value of type decimal64 with fraction
digits = 9 (see section 9.3 of [RFC6020]) with resolution of
0.000000001 seconds (1.0 ns), and with lossless conversion to/from
the 64-bit NTP timestamp as per section 6 of RFC [RFC5905]
5.4.3. Metric Units
The 95th Percentile of one-way PDV is expressed in seconds.
5.4.4. Calibration
Section 3.7.3 of [RFC7679] provides a means to quantify the
systematic and random errors of a time measurement. In-situ
calibration could be enabled with an internal loopback that includes
as much of the measurement system as possible, performs address
manipulation as needed, and provides some form of isolation (e.g.,
deterministic delay) to avoid send-receive interface contention.
Some portion of the random and systematic error can be characterized
this way.
For one-way delay measurements, the error calibration must include an
assessment of the internal clock synchronization with its external
reference (this internal clock is supplying timestamps for
measurement). In practice, the time offsets [RFC5905] of clocks at
both the source and destination are needed to estimate the systematic
error due to imperfect clock synchronization (the time offsets are
smoothed, thus the random variation is not usually represented in the
results).
time_offset The time value of the result is expressed in units of
seconds, as a signed value of type decimal64 with fraction digits
= 9 (see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
When a measurement controller requests a calibration measurement, the
loopback is applied and the result is output in the same format as a
normal measurement with additional indication that it is a
calibration result. In any measurement, the measurement function
SHOULD report its current estimate of time offset [RFC5905] as an
indicator of the degree of synchronization.
Both internal loopback calibration and clock synchronization can be
used to estimate the available accuracy of the Output Metric Units.
For example, repeated loopback delay measurements will reveal the
portion of the Output result resolution which is the result of system
noise, and thus inaccurate.
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5.5. Administrative items
5.5.1. Status
Current
5.5.2. Requester
This RFC number
5.5.3. Revision
1.0
5.5.4. Revision Date
YYYY-MM-DD
5.6. Comments and Remarks
Lost packets represent a challenge for delay variation metrics. See
section 4.1 of [RFC3393] and the delay variation applicability
statement[RFC5481] for extensive analysis and comparison of PDV and
an alternate metric, IPDV.
6. DNS Response Latency and Loss Registry Entries
This section gives initial registry entries for DNS Response Latency
and Loss from a network user's perspective, for a specific named
resource. The metric can be measured repeatedly using different
names. RFC 2681 [RFC2681] defines a Round-trip delay metric. We
build on that metric by specifying several of the input parameters to
precisely define two metrics for measuring DNS latency and loss.
Note to IANA: Each Registry "Name" below specifies a single registry
entry, whose output format varies in accordance with the name.
All column entries beside the ID, Name, Description, and Output
Reference Method categories are the same, thus this section proposes
two closely-related registry entries. As a result, IANA is also
asked to assign corresponding URLs to each Named Metric.
6.1. Summary
This category includes multiple indexes to the registry entries, the
element ID and metric name.
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6.1.1. ID (Identifier)
<insert numeric identifier, an integer>
IANA is asked to assign different numeric identifiers to each of the
two Named Metrics.
6.1.2. Name
RTDNS_Active_IP-UDP-Poisson_RFCXXXXsec6_Seconds_Raw
RLDNS_Active_IP-UDP-Poisson_RFCXXXXsec6_Logical_Raw
6.1.3. URI
URL: https://www.iana.org/ ... <name>
6.1.4. Description
This is a metric for DNS Response performance from a network user's
perspective, for a specific named resource. The metric can be
measured repeatedly using different resource names.
RTDNS: This metric assesses the response time, the interval from the
query transmission to the response.
RLDNS: This metric indicates that the response was deemed lost. In
other words, the response time exceeded the maximum waiting time.
6.1.5. Change Controller
IETF
6.1.6. Version (of Registry Format)
1.0
6.2. Metric Definition
This category includes columns to prompt the entry of all necessary
details related to the metric definition, including the RFC reference
and values of input factors, called fixed parameters.
6.2.1. Reference Definition
Mockapetris, P., "Domain names - implementation and specification",
STD 13, RFC 1035, November 1987. (and updates)
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[RFC1035]
Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip Delay
Metric for IPPM", RFC 2681, September 1999.
[RFC2681]
Section 2.4 of [RFC2681] provides the reference definition of the
singleton (single value) Round-trip delay metric. Section 3.4 of
[RFC2681] provides the reference definition expanded to cover a
multi-singleton sample. Note that terms such as singleton and sample
are defined in Section 11 of [RFC2330].
For DNS Response Latency, the entities in [RFC1035] must be mapped to
[RFC2681]. The Local Host with its User Program and Resolver take
the role of "Src", and the Foreign Name Server takes the role of
"Dst".
Note that although the [RFC2681] definition of "Round-trip-Delay
between Src and Dst at T" is directionally ambiguous in the text,
this metric tightens the definition further to recognize that the
host in the "Src" role will send the first packet to "Dst", and
ultimately receive the corresponding return packet from "Dst" (when
neither are lost).
Morton, A., "Round-trip Packet Loss Metrics", RFC 6673, August 2012.
[RFC6673]
Both response time and loss metrics employ a maximum waiting time for
received responses, so the count of lost packets to total packets
sent is the basis for the loss determination as per Section 4.3 of
[RFC6673].
6.2.2. Fixed Parameters
Type-P as defined in Section 13 of [RFC2330]:
o IPv4 header values:
* DSCP: set to 0
* TTL set to 255
* Protocol: set to 17 (UDP)
o IPv6 header values:
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* DSCP: set to 0
* Hop Count: set to 255
* Next Header: set to 17 (UDP)
* Flow Label: set to zero
* Extension Headers: none
o UDP header values:
* Source port: 53
* Destination port: 53
* Checksum: the checksum must be calculated and the non-zero
checksum included in the header
o Payload: The payload contains a DNS message as defined in RFC 1035
[RFC1035] with the following values:
* The DNS header section contains:
+ Identification (see the Run-time column)
+ QR: set to 0 (Query)
+ OPCODE: set to 0 (standard query)
+ AA: not set
+ TC: not set
+ RD: set to one (recursion desired)
+ RA: not set
+ RCODE: not set
+ QDCOUNT: set to one (only one entry)
+ ANCOUNT: not set
+ NSCOUNT: not set
+ ARCOUNT: not set
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* The Question section contains:
+ QNAME: the Fully Qualified Domain Name (FQDN) provided as
input for the test, see the Run-time column
+ QTYPE: the query type provided as input for the test, see
the Run-time column
+ QCLASS: set to 1 for IN
* The other sections do not contain any Resource Records.
Other measurement parameters:
o Tmax: a loss threshold waiting time (and to help disambiguate
queries)
* 5.0, expressed in units of seconds, as a positive value of type
decimal64 with fraction digits = 4 (see section 9.3 of
[RFC6020]) and with resolution of 0.0001 seconds (0.1 ms), with
lossless conversion to/from the 32-bit NTP timestamp as per
section 6 of [RFC5905].
Observation: reply packets will contain a DNS response and may
contain RRs.
6.3. Method of Measurement
This category includes columns for references to relevant sections of
the RFC(s) and any supplemental information needed to ensure an
unambiguous methods for implementations.
6.3.1. Reference Method
The methodology for this metric is defined as Type-P-Round-trip-
Delay-Poisson-Stream in section 2.6 of RFC 2681 [RFC2681] and section
3.6 of RFC 2681 [RFC2681] using the Type-P and Timeout defined under
Fixed Parameters.
The reference method distinguishes between long-delayed packets and
lost packets by implementing a maximum waiting time for packet
arrival. Tmax is the waiting time used as the threshold to declare a
response packet lost. Lost packets SHALL be designated as having
undefined delay and counted for the RLDNS metric.
The calculations on the delay (RTT) SHALL be performed on the
conditional distribution, conditioned on successful packet arrival
within Tmax. Also, when all packet delays are stored, the process
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which calculates the RTT value MUST enforce the Tmax threshold on
stored values before calculations. See section 4.1 of [RFC3393] for
details on the conditional distribution to exclude undefined values
of delay, and Section 5 of [RFC6703] for background on this analysis
choice.
The reference method requires some way to distinguish between
different packets in a stream to establish correspondence between
sending times and receiving times for each successfully-arriving
reply.
DNS Messages bearing Queries provide for random ID Numbers in the
Identification header field, so more than one query may be launched
while a previous request is outstanding when the ID Number is used.
Therefore, the ID Number MUST be retained at the Src and included
with each response packet to disambiguate packet reordering if it
occurs.
IF a DNS response does not arrive within Tmax, the response time
RTDNS is undefined, and RLDNS = 1. The Message ID SHALL be used to
disambiguate the successive queries that are otherwise identical.
Since the ID Number field is only 16 bits in length, it places a
limit on the number of simultaneous outstanding DNS queries during a
stress test from a single Src address.
Refer to Section 4.4 of [RFC6673] for expanded discussion of the
instruction to "send a Type-P packet back to the Src as quickly as
possible" in Section 2.6 of RFC 2681 [RFC2681]. However, the DNS
Server is expected to perform all required functions to prepare and
send a response, so the response time will include processing time
and network delay. Section 8 of [RFC6673] presents additional
requirements which SHALL be included in the method of measurement for
this metric.
In addition to operations described in [RFC2681], the Src MUST parse
the DNS headers of the reply and prepare the query response
information for subsequent reporting as a measured result, along with
the Round-Trip Delay.
6.3.2. Packet Stream Generation
This section gives the details of the packet traffic which is the
basis for measurement. In IPPM metrics, this is called the Stream,
and can easily be described by providing the list of stream
parameters.
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Section 11.1.3 of RFC 2681 [RFC2330] provides three methods to
generate Poisson sampling intervals. The reciprocal of lambda is the
average packet spacing, thus the Run-time Parameter is
Reciprocal_lambda = 1/lambda, in seconds.
Method 3 is used, where given a start time (Run-time Parameter), the
subsequent send times are all computed prior to measurement by
computing the pseudo-random distribution of inter-packet send times,
(truncating the distribution as specified in the Run-time
Parameters), and the Src sends each packet at the computed times.
Note that Trunc is the upper limit on inter-packet times in the
Poisson distribution. A random value greater than Trunc is set equal
to Trunc instead.
6.3.3. Traffic Filtering (observation) Details
NA
6.3.4. Sampling Distribution
NA
6.3.5. Run-time Parameters and Data Format
Run-time Parameters are input factors that must be determined,
configured into the measurement system, and reported with the results
for the context to be complete.
Src the IP address of the host in the Src Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see Section 4 of [RFC6991])
Dst the IP address of the host in the Dst Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see section 4 of [RFC6991])
T0 a time, the start of a measurement interval, (format "date-and-
time" as specified in Section 5.6 of [RFC3339], see also Section 3
of [RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a start time is unspecified
and Tf is to be interpreted as the Duration of the measurement
interval. The start time is controlled through other means.
Tf a time, the end of a measurement interval, (format "date-and-time"
as specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
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[RFC2330]. When T0 is "all-zeros", a end time date is ignored and
Tf is interpreted as the Duration of the measurement interval.
Reciprocal_lambda average packet interval for Poisson Streams
expressed in units of seconds, as a positive value of type
decimal64 with fraction digits = 4 (see section 9.3 of [RFC6020])
with resolution of 0.0001 seconds (0.1 ms), and with lossless
conversion to/from the 32-bit NTP timestamp as per section 6 of
[RFC5905].
Trunc Upper limit on Poisson distribution expressed in units of
seconds, as a positive value of type decimal64 with fraction
digits = 4 (see section 9.3 of [RFC6020]) with resolution of
0.0001 seconds (0.1 ms), and with lossless conversion to/from the
32-bit NTP timestamp as per section 6 of [RFC5905] (values above
this limit will be clipped and set to the limit value).
ID The 16-bit identifier assigned by the program that generates the
query, and which must vary in successive queries (a list of IDs is
needed), see Section 4.1.1 of [RFC1035]. This identifier is
copied into the corresponding reply and can be used by the
requester (Src) to match-up replies to outstanding queries.
QNAME The domain name of the Query, formatted as specified in
section 4 of [RFC6991].
QTYPE The Query Type, which will correspond to the IP address family
of the query (decimal 1 for IPv4 or 28 for IPv6, formatted as a
uint16, as per section 9.2 of [RFC6020].
6.3.6. Roles
Src launches each packet and waits for return transmissions from
Dst.
Dst waits for each packet from Src and sends a return packet to Src.
6.4. Output
This category specifies all details of the Output of measurements
using the metric.
6.4.1. Type
Raw -- for each DNS Query packet sent, sets of values as defined in
the next column, including the status of the response, only assigning
delay values to successful query-response pairs.
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6.4.2. Reference Definition
For all outputs:
T the time the DNS Query was sent during the measurement interval,
(format "date-and-time" as specified in Section 5.6 of [RFC3339],
see also Section 3 of [RFC6991]). The UTC Time Zone is required
by Section 6.1 of [RFC2330].
dT The time value of the round-trip delay to receive the DNS
response, expressed in units of seconds, as a positive value of
type decimal64 with fraction digits = 9 (see section 9.3 of
[RFC6020]) with resolution of 0.000000001 seconds (1.0 ns), and
with lossless conversion to/from the 64-bit NTP timestamp as per
section 6 of RFC [RFC5905]. This value is undefined when the
response packet is not received at Src within waiting time Tmax
seconds.
Rcode The value of the Rcode field in the DNS response header,
expressed as a uint64 as specified in section 9.2 of [RFC6020].
Non-zero values convey errors in the response, and such replies
must be analyzed separately from successful requests.
6.4.3. Metric Units
RTDNS: Round-trip Delay, dT, is expressed in seconds.
RTLDNS: the Logical value, where 1 = Lost and 0 = Received.
6.4.4. Calibration
Section 3.7.3 of [RFC7679] provides a means to quantify the
systematic and random errors of a time measurement. In-situ
calibration could be enabled with an internal loopback at the Source
host that includes as much of the measurement system as possible,
performs address and payload manipulation as needed, and provides
some form of isolation (e.g., deterministic delay) to avoid send-
receive interface contention. Some portion of the random and
systematic error can be characterized this way.
When a measurement controller requests a calibration measurement, the
loopback is applied and the result is output in the same format as a
normal measurement with additional indication that it is a
calibration result.
Both internal loopback calibration and clock synchronization can be
used to estimate the available accuracy of the Output Metric Units.
For example, repeated loopback delay measurements will reveal the
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portion of the Output result resolution which is the result of system
noise, and thus inaccurate.
6.5. Administrative items
6.5.1. Status
Current
6.5.2. Requester
This RFC number
6.5.3. Revision
1.0
6.5.4. Revision Date
YYYY-MM-DD
6.6. Comments and Remarks
None
7. UDP Poisson One-way Delay and Loss Registry Entries
This section specifies five initial registry entries for the UDP
Poisson One-way Delay, and one for UDP Poisson One-way Loss.
IANA Note: Registry "Name" below specifies multiple registry entries,
whose output format varies according to the <statistic> element of
the name that specifies one form of statistical summary. There is an
additional metric name for the Loss metric.
All column entries beside the ID, Name, Description, and Output
Reference Method categories are the same, thus this section proposes
six closely-related registry entries. As a result, IANA is also
asked to assign corresponding URLs to each Named Metric.
7.1. Summary
This category includes multiple indexes to the registry entries, the
element ID and metric name.
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7.1.1. ID (Identifier)
IANA is asked to assign different numeric identifiers to each of the
six Metrics.
7.1.2. Name
OWDelay_Active_IP-UDP-Poisson-
Payload250B_RFCXXXXsec7_Seconds_<statistic>
where <statistic> is one of:
o 95Percentile
o Mean
o Min
o Max
o StdDev
OWLoss_Active_IP-UDP-Poisson-
Payload250B_RFCXXXXsec7_Percent_LossRatio
7.1.3. URI
URL: https://www.iana.org/ ... <name>
7.1.4. Description
OWDelay: This metric assesses the delay of a stream of packets
exchanged between two hosts (or measurement points), and reports the
<statistic> One-way delay for all successfully exchanged packets
based on their conditional delay distribution.
where <statistic> is one of:
o 95Percentile
o Mean
o Min
o Max
o StdDev
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OWLoss: This metric assesses the loss ratio of a stream of packets
exchanged between two hosts (which are the two measurement points),
and the Output is the One-way loss ratio for all successfully
received packets expressed as a percentage.
7.2. Metric Definition
This category includes columns to prompt the entry of all necessary
details related to the metric definition, including the RFC reference
and values of input factors, called fixed parameters.
7.2.1. Reference Definition
For Delay:
Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, Ed., "A One-
Way Delay Metric for IP Performance Metrics (IPPM)", STD 81, RFC
7679, DOI 10.17487/RFC7679, January 2016, <http://www.rfc-
editor.org/info/rfc7679>.
[RFC7679]
Morton, A., and Stephan, E., "Spatial Composition of Metrics", RFC
6049, January 2011.
[RFC6049]
Section 3.4 of [RFC7679] provides the reference definition of the
singleton (single value) One-way delay metric. Section 4.4 of
[RFC7679] provides the reference definition expanded to cover a
multi-value sample. Note that terms such as singleton and sample are
defined in Section 11 of [RFC2330].
Only successful packet transfers with finite delay are included in
the sample, as prescribed in section 4.1.2 of [RFC6049].
For loss:
Almes, G., Kalidini, S., Zekauskas, M., and A. Morton, Ed., "A One-
Way Loss Metric for IP Performance Metrics (IPPM)", RFC 7680, DOI
10.17487/RFC7680, January 2016, <http://www.rfc-editor.org/info/
rfc7680>.
Section 2.4 of [RFC7680] provides the reference definition of the
singleton (single value) one-way loss metric. Section 3.4 of
[RFC7680] provides the reference definition expanded to cover a
multi-singleton sample. Note that terms such as singleton and sample
are defined in Section 11 of [RFC2330].
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7.2.2. Fixed Parameters
Type-P:
o IPv4 header values:
* DSCP: set to 0
* TTL: set to 255
* Protocol: Set to 17 (UDP)
o IPv6 header values:
* DSCP: set to 0
* Hop Count: set to 255
* Next Header: set to 17 (UDP)
* Flow Label: set to zero
* Extension Headers: none
o UDP header values:
* Checksum: the checksum MUST be calculated and the non-zero
checksum included in the header
o UDP Payload: TWAMP Test Packet Formats, Section 4.1.2 of [RFC5357]
* Security features in use influence the number of Padding
octets.
* 250 octets total, including the TWAMP format type, which MUST
be reported.
Other measurement parameters:
Tmax: a loss threshold waiting time with value 3.0, expressed in
units of seconds, as a positive value of type decimal64 with
fraction digits = 4 (see section 9.3 of [RFC6020]) and with
resolution of 0.0001 seconds (0.1 ms), with lossless conversion
to/from the 32-bit NTP timestamp as per section 6 of [RFC5905].
See the Packet Stream generation category for two additional Fixed
Parameters.
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7.3. Method of Measurement
This category includes columns for references to relevant sections of
the RFC(s) and any supplemental information needed to ensure an
unambiguous methods for implementations.
7.3.1. Reference Method
The methodology for this metric is defined as Type-P-One-way-Delay-
Poisson-Stream in section 3.6 of [RFC7679] and section 4.6 of
[RFC7679] using the Type-P and Tmax defined under Fixed Parameters.
The reference method distinguishes between long-delayed packets and
lost packets by implementing a maximum waiting time for packet
arrival. Tmax is the waiting time used as the threshold to declare a
packet lost. Lost packets SHALL be designated as having undefined
delay, and counted for the OWLoss metric.
The calculations on the one-way delay SHALL be performed on the
conditional distribution, conditioned on successful packet arrival
within Tmax. Also, when all packet delays are stored, the process
which calculates the one-way delay value MUST enforce the Tmax
threshold on stored values before calculations. See section 4.1 of
[RFC3393] for details on the conditional distribution to exclude
undefined values of delay, and Section 5 of [RFC6703] for background
on this analysis choice.
The reference method requires some way to distinguish between
different packets in a stream to establish correspondence between
sending times and receiving times for each successfully-arriving
packet.
Since a standard measurement protocol is employed [RFC5357], then the
measurement process will determine the sequence numbers or timestamps
applied to test packets after the Fixed and Runtime parameters are
passed to that process. The measurement protocol dictates the format
of sequence numbers and time-stamps conveyed in the TWAMP-Test packet
payload.
7.3.2. Packet Stream Generation
This section gives the details of the packet traffic which is the
basis for measurement. In IPPM metrics, this is called the Stream,
and can easily be described by providing the list of stream
parameters.
Section 11.1.3 of RFC 2681 [RFC2330] provides three methods to
generate Poisson sampling intervals. The reciprocal of lambda is the
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average packet spacing, thus the Run-time Parameter is
Reciprocal_lambda = 1/lambda, in seconds.
Method 3 SHALL be used, where given a start time (Run-time
Parameter), the subsequent send times are all computed prior to
measurement by computing the pseudo-random distribution of inter-
packet send times, (truncating the distribution as specified in the
Parameter Trunc), and the Src sends each packet at the computed
times.
Note that Trunc is the upper limit on inter-packet times in the
Poisson distribution. A random value greater than Trunc is set equal
to Trunc instead.
Reciprocal_lambda average packet interval for Poisson Streams
expressed in units of seconds, as a positive value of type
decimal64 with fraction digits = 4 (see section 9.3 of [RFC6020])
with resolution of 0.0001 seconds (0.1 ms), and with lossless
conversion to/from the 32-bit NTP timestamp as per section 6 of
[RFC5905]. Reciprocal_lambda = 1 second.
Trunc Upper limit on Poisson distribution expressed in units of
seconds, as a positive value of type decimal64 with fraction
digits = 4 (see section 9.3 of [RFC6020]) with resolution of
0.0001 seconds (0.1 ms), and with lossless conversion to/from the
32-bit NTP timestamp as per section 6 of [RFC5905] (values above
this limit will be clipped and set to the limit value). Trunc =
30.0000 seconds.
7.3.3. Traffic Filtering (observation) Details
NA
7.3.4. Sampling Distribution
NA
7.3.5. Run-time Parameters and Data Format
Run-time Parameters are input factors that must be determined,
configured into the measurement system, and reported with the results
for the context to be complete.
Src the IP address of the host in the Src Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see Section 4 of [RFC6991])
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Dst the IP address of the host in the Dst Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see section 4 of [RFC6991])
T0 a time, the start of a measurement interval, (format "date-and-
time" as specified in Section 5.6 of [RFC3339], see also Section 3
of [RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a start time is unspecified
and Tf is to be interpreted as the Duration of the measurement
interval. The start time is controlled through other means.
Tf a time, the end of a measurement interval, (format "date-and-time"
as specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a end time date is ignored and
Tf is interpreted as the Duration of the measurement interval.
7.3.6. Roles
Src launches each packet and waits for return transmissions from
Dst. This is the TWAMP Session-Sender.
Dst waits for each packet from Src and sends a return packet to Src.
This is the TWAMP Session-Reflector.
7.4. Output
This category specifies all details of the Output of measurements
using the metric.
7.4.1. Type
See subsection titles below for Types.
7.4.2. Reference Definition
For all output types ---
T0 the start of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
Tf the end of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
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For LossRatio -- the count of lost packets to total packets sent is
the basis for the loss ratio calculation as per Section 4.1 of
[RFC7680].
For each <statistic>, one of the following sub-sections apply:
7.4.2.1. Percentile95
The 95th percentile SHALL be calculated using the conditional
distribution of all packets with a finite value of One-way delay
(undefined delays are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3 of [RFC3393] for details on the percentile statistic
(where Round-trip delay should be substituted for "ipdv").
The percentile = 95, meaning that the reported delay, "95Percentile",
is the smallest value of one-way delay for which the Empirical
Distribution Function (EDF), F(95Percentile) >= 95% of the singleton
one-way delay values in the conditional distribution. See section
11.3 of [RFC2330] for the definition of the percentile statistic
using the EDF.
95Percentile The time value of the result is expressed in units of
seconds, as a positive value of type decimal64 with fraction
digits = 9 (see section 9.3 of [RFC6020]) with resolution of
0.000000001 seconds (1.0 ns), and with lossless conversion to/from
the 64-bit NTP timestamp as per section 6 of RFC [RFC5905]
7.4.2.2. Mean
The mean SHALL be calculated using the conditional distribution of
all packets with a finite value of One-way delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.2.2 of [RFC6049] for details on calculating this
statistic, and 4.2.3 of [RFC6049].
Mean The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
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seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
7.4.2.3. Min
The minimum SHALL be calculated using the conditional distribution of
all packets with a finite value of One-way delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3.2 of [RFC6049] for details on calculating this
statistic, and 4.3.3 of [RFC6049].
Min The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
7.4.2.4. Max
The maximum SHALL be calculated using the conditional distribution of
all packets with a finite value of One-way delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3.2 of [RFC6049] for a closely related method for
calculating this statistic, and 4.3.3 of [RFC6049]. The formula is
as follows:
Max = (FiniteDelay [j])
such that for some index, j, where 1 <= j <= N
FiniteDelay[j] >= FiniteDelay[n] for all n
Max The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
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7.4.2.5. Std_Dev
The Std_Dev SHALL be calculated using the conditional distribution of
all packets with a finite value of One-way delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 6.1.4 of [RFC6049] for a closely related method for
calculating this statistic. The formula is the classic calculation
for standard deviation of a population.
Define Population Std_Dev_Delay as follows:
(where all packets n = 1 through N have a value for Delay[n],
and MeanDelay calculated as in 7.4.2.2), and SQRT[] is the
Square Root function:
_ _
| N |
| --- |
| 1 \ 2 |
Std_Dev = SQRT | ------- > (Delay[n] - MeanDelay) |
| (N) / |
| --- |
| n = 1 |
|_ _|
Std_Dev The time value of the result is expressed in units of
seconds, as a positive value of type decimal64 with fraction
digits = 9 (see section 9.3 of [RFC6020]) with resolution of
0.000000001 seconds (1.0 ns), and with lossless conversion to/from
the 64-bit NTP timestamp as per section 6 of RFC [RFC5905]
7.4.3. Metric Units
The <statistic> of One-way Delay is expressed in seconds.
The One-way Loss Ratio is expressed as a percentage of lost packets
to total packets sent.
7.4.4. Calibration
Section 3.7.3 of [RFC7679] provides a means to quantify the
systematic and random errors of a time measurement. In-situ
calibration could be enabled with an internal loopback that includes
as much of the measurement system as possible, performs address
manipulation as needed, and provides some form of isolation (e.g.,
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deterministic delay) to avoid send-receive interface contention.
Some portion of the random and systematic error can be characterized
this way.
For one-way delay measurements, the error calibration must include an
assessment of the internal clock synchronization with its external
reference (this internal clock is supplying timestamps for
measurement). In practice, the time offsets [RFC5905] of clocks at
both the source and destination are needed to estimate the systematic
error due to imperfect clock synchronization (the time offsets
[RFC5905] are smoothed, thus the random variation is not usually
represented in the results).
time_offset The time value of the result is expressed in units of
seconds, as a signed value of type decimal64 with fraction digits
= 9 (see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
When a measurement controller requests a calibration measurement, the
loopback is applied and the result is output in the same format as a
normal measurement with additional indication that it is a
calibration result. In any measurement, the measurement function
SHOULD report its current estimate of time offset [RFC5905] as an
indicator of the degree of synchronization.
Both internal loopback calibration and clock synchronization can be
used to estimate the available accuracy of the Output Metric Units.
For example, repeated loopback delay measurements will reveal the
portion of the Output result resolution which is the result of system
noise, and thus inaccurate.
7.5. Administrative items
7.5.1. Status
Current
7.5.2. Requester
This RFC number
7.5.3. Revision
1.0
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7.5.4. Revision Date
YYYY-MM-DD
7.6. Comments and Remarks
None
8. UDP Periodic One-way Delay and Loss Registry Entries
This section specifies five initial registry entries for the UDP
Periodic One-way Delay, and one for UDP Periodic One-way Loss.
IANA Note: Registry "Name" below specifies multiple registry entries,
whose output format varies according to the <statistic> element of
the name that specifies one form of statistical summary. There is an
additional metric name for the Loss metric.
All column entries beside the ID, Name, Description, and Output
Reference Method categories are the same, thus this section proposes
six closely-related registry entries. As a result, IANA is also
asked to assign corresponding URLs to each Named Metric.
8.1. Summary
This category includes multiple indexes to the registry entries, the
element ID and metric name.
8.1.1. ID (Identifier)
IANA is asked to assign a different numeric identifiers to each of
the six Metrics.
8.1.2. Name
OWDelay_Active_IP-UDP-Periodic20m-
Payload142B_RFCXXXXsec8_Seconds_<statistic>
where <statistic> is one of:
o 95Percentile
o Mean
o Min
o Max
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o StdDev
OWLoss_Active_IP-UDP-Periodic-
Payload142B_RFCXXXXsec8_Percent_LossRatio
8.1.3. URI
URL: https://www.iana.org/ ... <name>
8.1.4. Description
OWDelay: This metric assesses the delay of a stream of packets
exchanged between two hosts (or measurement points), and reports the
<statistic> One-way delay for all successfully exchanged packets
based on their conditional delay distribution.
where <statistic> is one of:
o 95Percentile
o Mean
o Min
o Max
o StdDev
OWLoss: This metric assesses the loss ratio of a stream of packets
exchanged between two hosts (which are the two measurement points),
and the Output is the One-way loss ratio for all successfully
received packets expressed as a percentage.
8.2. Metric Definition
This category includes columns to prompt the entry of all necessary
details related to the metric definition, including the RFC reference
and values of input factors, called fixed parameters.
8.2.1. Reference Definition
For Delay:
Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, Ed., "A One-
Way Delay Metric for IP Performance Metrics (IPPM)", STD 81, RFC
7679, DOI 10.17487/RFC7679, January 2016, <http://www.rfc-
editor.org/info/rfc7679>.
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[RFC7679]
Morton, A., and Stephan, E., "Spatial Composition of Metrics", RFC
6049, January 2011.
[RFC6049]
Section 3.4 of [RFC7679] provides the reference definition of the
singleton (single value) One-way delay metric. Section 4.4 of
[RFC7679] provides the reference definition expanded to cover a
multi-value sample. Note that terms such as singleton and sample are
defined in Section 11 of [RFC2330].
Only successful packet transfers with finite delay are included in
the sample, as prescribed in section 4.1.2 of [RFC6049].
For loss:
Almes, G., Kalidini, S., Zekauskas, M., and A. Morton, Ed., "A One-
Way Loss Metric for IP Performance Metrics (IPPM)", RFC 7680, DOI
10.17487/RFC7680, January 2016, <http://www.rfc-editor.org/info/
rfc7680>.
Section 2.4 of [RFC7680] provides the reference definition of the
singleton (single value) one-way loss metric. Section 3.4 of
[RFC7680] provides the reference definition expanded to cover a
multi-singleton sample. Note that terms such as singleton and sample
are defined in Section 11 of [RFC2330].
8.2.2. Fixed Parameters
Type-P:
o IPv4 header values:
* DSCP: set to 0
* TTL: set to 255
* Protocol: Set to 17 (UDP)
o IPv6 header values:
* DSCP: set to 0
* Hop Count: set to 255
* Next Header: set to 17 (UDP)
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* Flow Label: set to zero
* Extension Headers: none
o UDP header values:
* Checksum: the checksum MUST be calculated and the non-zero
checksum included in the header
o UDP Payload: TWAMP Test Packet Formats, Section 4.1.2 of [RFC5357]
* Security features in use influence the number of Padding
octets.
* 142 octets total, including the TWAMP format (and format type
MUST be reported, if used)
Other measurement parameters:
Tmax: a loss threshold waiting time with value 3.0, expressed in
units of seconds, as a positive value of type decimal64 with
fraction digits = 4 (see section 9.3 of [RFC6020]) and with
resolution of 0.0001 seconds (0.1 ms), with lossless conversion
to/from the 32-bit NTP timestamp as per section 6 of [RFC5905].
See the Packet Stream generation category for two additional Fixed
Parameters.
8.3. Method of Measurement
This category includes columns for references to relevant sections of
the RFC(s) and any supplemental information needed to ensure an
unambiguous methods for implementations.
8.3.1. Reference Method
The methodology for this metric is defined as Type-P-One-way-Delay-
Poisson-Stream in section 3.6 of [RFC7679] and section 4.6 of
[RFC7679] using the Type-P and Tmax defined under Fixed Parameters.
However, a Periodic stream is used, as defined in [RFC3432].
The reference method distinguishes between long-delayed packets and
lost packets by implementing a maximum waiting time for packet
arrival. Tmax is the waiting time used as the threshold to declare a
packet lost. Lost packets SHALL be designated as having undefined
delay, and counted for the OWLoss metric.
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The calculations on the one-way delay SHALL be performed on the
conditional distribution, conditioned on successful packet arrival
within Tmax. Also, when all packet delays are stored, the process
which calculates the one-way delay value MUST enforce the Tmax
threshold on stored values before calculations. See section 4.1 of
[RFC3393] for details on the conditional distribution to exclude
undefined values of delay, and Section 5 of [RFC6703] for background
on this analysis choice.
The reference method requires some way to distinguish between
different packets in a stream to establish correspondence between
sending times and receiving times for each successfully-arriving
packet.
Since a standard measurement protocol is employed [RFC5357], then the
measurement process will determine the sequence numbers or timestamps
applied to test packets after the Fixed and Runtime parameters are
passed to that process. The measurement protocol dictates the format
of sequence numbers and time-stamps conveyed in the TWAMP-Test packet
payload.
8.3.2. Packet Stream Generation
This section gives the details of the packet traffic which is the
basis for measurement. In IPPM metrics, this is called the Stream,
and can easily be described by providing the list of stream
parameters.
Section 3 of [RFC3432] prescribes the method for generating Periodic
streams using associated parameters.
incT the nominal duration of inter-packet interval, first bit to
first bit, with value 0.0200 expressed in units of seconds, as a
positive value of type decimal64 with fraction digits = 4 (see
section 9.3 of [RFC6020]) and with resolution of 0.0001 seconds
(0.1 ms), with lossless conversion to/from the 32-bit NTP
timestamp as per section 6 of [RFC5905].
dT the duration of the interval for allowed sample start times, with
value 1.0000, expressed in units of seconds, as a positive value
of type decimal64 with fraction digits = 4 (see section 9.3 of
[RFC6020]) and with resolution of 0.0001 seconds (0.1 ms), with
lossless conversion to/from the 32-bit NTP timestamp as per
section 6 of [RFC5905].
T0 the actual start time of the periodic stream, determined from T0
and dT.
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NOTE: an initiation process with a number of control exchanges
resulting in unpredictable start times (within a time interval) may
be sufficient to avoid synchronization of periodic streams, and
therefore a valid replacement for selecting a start time at random
from a fixed interval.
These stream parameters will be specified as Run-time parameters.
8.3.3. Traffic Filtering (observation) Details
NA
8.3.4. Sampling Distribution
NA
8.3.5. Run-time Parameters and Data Format
Run-time Parameters are input factors that must be determined,
configured into the measurement system, and reported with the results
for the context to be complete.
Src the IP address of the host in the Src Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see Section 4 of [RFC6991])
Dst the IP address of the host in the Dst Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see section 4 of [RFC6991])
T0 a time, the start of a measurement interval, (format "date-and-
time" as specified in Section 5.6 of [RFC3339], see also Section 3
of [RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a start time is unspecified
and Tf is to be interpreted as the Duration of the measurement
interval. The start time is controlled through other means.
Tf a time, the end of a measurement interval, (format "date-and-time"
as specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a end time date is ignored and
Tf is interpreted as the Duration of the measurement interval.
8.3.6. Roles
Src launches each packet and waits for return transmissions from
Dst. This is the TWAMP Session-Sender.
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Dst waits for each packet from Src and sends a return packet to Src.
This is the TWAMP Session-Reflector.
8.4. Output
This category specifies all details of the Output of measurements
using the metric.
8.4.1. Type
See subsection titles in Reference Definition for Latency Types.
8.4.2. Reference Definition
For all output types ---
T0 the start of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
Tf the end of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
For LossRatio -- the count of lost packets to total packets sent is
the basis for the loss ratio calculation as per Section 4.1 of
[RFC7680].
For each <statistic>, one of the following sub-sections apply:
8.4.2.1. Percentile95
The 95th percentile SHALL be calculated using the conditional
distribution of all packets with a finite value of One-way delay
(undefined delays are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3 of [RFC3393] for details on the percentile statistic
(where Round-trip delay should be substituted for "ipdv").
The percentile = 95, meaning that the reported delay, "95Percentile",
is the smallest value of one-way delay for which the Empirical
Distribution Function (EDF), F(95Percentile) >= 95% of the singleton
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one-way delay values in the conditional distribution. See section
11.3 of [RFC2330] for the definition of the percentile statistic
using the EDF.
95Percentile The time value of the result is expressed in units of
seconds, as a positive value of type decimal64 with fraction
digits = 9 (see section 9.3 of [RFC6020]) with resolution of
0.000000001 seconds (1.0 ns), and with lossless conversion to/from
the 64-bit NTP timestamp as per section 6 of RFC [RFC5905]
8.4.2.2. Mean
The mean SHALL be calculated using the conditional distribution of
all packets with a finite value of One-way delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.2.2 of [RFC6049] for details on calculating this
statistic, and 4.2.3 of [RFC6049].
Mean The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
8.4.2.3. Min
The minimum SHALL be calculated using the conditional distribution of
all packets with a finite value of One-way delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3.2 of [RFC6049] for details on calculating this
statistic, and 4.3.3 of [RFC6049].
Min The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
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8.4.2.4. Max
The maximum SHALL be calculated using the conditional distribution of
all packets with a finite value of One-way delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3.2 of [RFC6049] for a closely related method for
calculating this statistic, and 4.3.3 of [RFC6049]. The formula is
as follows:
Max = (FiniteDelay [j])
such that for some index, j, where 1 <= j <= N
FiniteDelay[j] >= FiniteDelay[n] for all n
Max The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
8.4.2.5. Std_Dev
The Std_Dev SHALL be calculated using the conditional distribution of
all packets with a finite value of One-way delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3.2 of [RFC6049] for a closely related method for
calculating this statistic, and 4.3.3 of [RFC6049]. The formula is
the classic calculation for standard deviation of a population.
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Define Population Std_Dev_Delay as follows:
(where all packets n = 1 through N have a value for Delay[n],
and MeanDelay calculated as in 7.4.2.2), and SQRT[] is the
Square Root function:
_ _
| N |
| --- |
| 1 \ 2 |
Std_Dev = SQRT | ------- > (Delay[n] - MeanDelay) |
| (N) / |
| --- |
| n = 1 |
|_ _|
Std_Dev The time value of the result is expressed in units of
seconds, as a positive value of type decimal64 with fraction
digits = 9 (see section 9.3 of [RFC6020]) with resolution of
0.000000001 seconds (1.0 ns), and with lossless conversion to/from
the 64-bit NTP timestamp as per section 6 of RFC [RFC5905]
8.4.3. Metric Units
The <statistic> of One-way Delay is expressed in seconds, where
<statistic> is one of:
o 95Percentile
o Mean
o Min
o Max
o StdDev
The One-way Loss Ratio is expressed as a percentage of lost packets
to total packets sent.
8.4.4. Calibration
Section 3.7.3 of [RFC7679] provides a means to quantify the
systematic and random errors of a time measurement. In-situ
calibration could be enabled with an internal loopback that includes
as much of the measurement system as possible, performs address
manipulation as needed, and provides some form of isolation (e.g.,
deterministic delay) to avoid send-receive interface contention.
Some portion of the random and systematic error can be characterized
this way.
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For one-way delay measurements, the error calibration must include an
assessment of the internal clock synchronization with its external
reference (this internal clock is supplying timestamps for
measurement). In practice, the time offsets [RFC5905] of clocks at
both the source and destination are needed to estimate the systematic
error due to imperfect clock synchronization (the time offsets
[RFC5905] are smoothed, thus the random variation is not usually
represented in the results).
time_offset The time value of the result is expressed in units of
seconds, as a signed value of type decimal64 with fraction digits
= 9 (see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
When a measurement controller requests a calibration measurement, the
loopback is applied and the result is output in the same format as a
normal measurement with additional indication that it is a
calibration result. In any measurement, the measurement function
SHOULD report its current estimate of time offset [RFC5905] as an
indicator of the degree of synchronization.
Both internal loopback calibration and clock synchronization can be
used to estimate the available accuracy of the Output Metric Units.
For example, repeated loopback delay measurements will reveal the
portion of the Output result resolution which is the result of system
noise, and thus inaccurate.
8.5. Administrative items
8.5.1. Status
Current
8.5.2. Requester
This RFC number
8.5.3. Revision
1.0
8.5.4. Revision Date
YYYY-MM-DD
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8.6. Comments and Remarks
None.
9. ICMP Round-trip Latency and Loss Registry Entries
This section specifies three initial registry entries for the ICMP
Round-trip Latency, and another entry for ICMP Round-trip Loss Ratio.
IANA Note: Registry "Name" below specifies multiple registry entries,
whose output format varies according to the <statistic> element of
the name that specifies one form of statistical summary. There is an
additional metric name for the Loss metric.
All column entries beside the ID, Name, Description, and Output
Reference Method categories are the same, thus this section proposes
two closely-related registry entries. As a result, IANA is also
asked to assign corresponding URLs to each Named Metric.
9.1. Summary
This category includes multiple indexes to the registry entry: the
element ID and metric name.
9.1.1. ID (Identifier)
IANA is asked to assign different numeric identifiers to each of the
four Named Metrics.
9.1.2. Name
RTDelay_Active_IP-ICMP-SendOnRcv_RFCXXXXsec9_Seconds_<statistic>
where <statistic> is one of:
o Mean
o Min
o Max
RTLoss_Active_IP-ICMP-SendOnRcv_RFCXXXXsec9_Percent_LossRatio
9.1.3. URI
URL: https://www.iana.org/ ... <name>
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9.1.4. Description
RTDelay: This metric assesses the delay of a stream of ICMP packets
exchanged between two hosts (which are the two measurement points),
and the Output is the Round-trip delay for all successfully exchanged
packets expressed as the <statistic> of their conditional delay
distribution, where <statistic> is one of:
o Mean
o Min
o Max
RTLoss: This metric assesses the loss ratio of a stream of ICMP
packets exchanged between two hosts (which are the two measurement
points), and the Output is the Round-trip loss ratio for all
successfully exchanged packets expressed as a percentage.
9.1.5. Change Controller
IETF
9.1.6. Version (of Registry Format)
1.0
9.2. Metric Definition
This category includes columns to prompt the entry of all necessary
details related to the metric definition, including the RFC reference
and values of input factors, called fixed parameters.
9.2.1. Reference Definition
Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip Delay
Metric for IPPM", RFC 2681, September 1999.
[RFC2681]
Section 2.4 of [RFC2681] provides the reference definition of the
singleton (single value) Round-trip delay metric. Section 3.4 of
[RFC2681] provides the reference definition expanded to cover a
multi-singleton sample. Note that terms such as singleton and sample
are defined in Section 11 of [RFC2330].
Note that although the [RFC2681] definition of "Round-trip-Delay
between Src and Dst" is directionally ambiguous in the text, this
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metric tightens the definition further to recognize that the host in
the "Src" role will send the first packet to "Dst", and ultimately
receive the corresponding return packet from "Dst" (when neither are
lost).
Finally, note that the variable "dT" is used in [RFC2681] to refer to
the value of Round-trip delay in metric definitions and methods. The
variable "dT" has been re-used in other IPPM literature to refer to
different quantities, and cannot be used as a global variable name.
Morton, A., "Round-trip Packet Loss Metrics", RFC 6673, August 2012.
[RFC6673]
Both delay and loss metrics employ a maximum waiting time for
received packets, so the count of lost packets to total packets sent
is the basis for the loss ratio calculation as per Section 6.1 of
[RFC6673].
9.2.2. Fixed Parameters
Type-P as defined in Section 13 of [RFC2330]:
o IPv4 header values:
* DSCP: set to 0
* TTL: set to 255
* Protocol: Set to 01 (ICMP)
o IPv6 header values:
* DSCP: set to 0
* Hop Count: set to 255
* Next Header: set to 128 decimal (ICMP)
* Flow Label: set to zero
* Extension Headers: none
o ICMP header values:
* Type: 8 (Echo Request)
* Code: 0
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* Checksum: the checksum MUST be calculated and the non-zero
checksum included in the header
* (Identifier and Sequence Number set at Run-Time)
o ICMP Payload
* total of 32 bytes of random info, constant per test.
Other measurement parameters:
o Tmax: a loss threshold waiting time
* 3.0, expressed in units of seconds, as a positive value of type
decimal64 with fraction digits = 4 (see section 9.3 of
[RFC6020]) and with resolution of 0.0001 seconds (0.1 ms), with
lossless conversion to/from the 32-bit NTP timestamp as per
section 6 of [RFC5905].
9.3. Method of Measurement
This category includes columns for references to relevant sections of
the RFC(s) and any supplemental information needed to ensure an
unambiguous methods for implementations.
9.3.1. Reference Method
The methodology for this metric is defined as Type-P-Round-trip-
Delay-Poisson-Stream in section 2.6 of RFC 2681 [RFC2681] and section
3.6 of RFC 2681 [RFC2681] using the Type-P and Tmax defined under
Fixed Parameters.
The reference method distinguishes between long-delayed packets and
lost packets by implementing a maximum waiting time for packet
arrival. Tmax is the waiting time used as the threshold to declare a
packet lost. Lost packets SHALL be designated as having undefined
delay, and counted for the RTLoss metric.
The calculations on the delay (RTD) SHALL be performed on the
conditional distribution, conditioned on successful packet arrival
within Tmax. Also, when all packet delays are stored, the process
which calculates the RTD value MUST enforce the Tmax threshold on
stored values before calculations. See section 4.1 of [RFC3393] for
details on the conditional distribution to exclude undefined values
of delay, and Section 5 of [RFC6703] for background on this analysis
choice.
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The reference method requires some way to distinguish between
different packets in a stream to establish correspondence between
sending times and receiving times for each successfully-arriving
packet. Sequence numbers or other send-order identification MUST be
retained at the Src or included with each packet to disambiguate
packet reordering if it occurs.
The measurement process will determine the sequence numbers applied
to test packets after the Fixed and Runtime parameters are passed to
that process. The ICMP measurement process and protocol will dictate
the format of sequence numbers and other identifiers.
Refer to Section 4.4 of [RFC6673] for expanded discussion of the
instruction to "send a Type-P packet back to the Src as quickly as
possible" in Section 2.6 of RFC 2681 [RFC2681]. Section 8 of
[RFC6673] presents additional requirements which MUST be included in
the method of measurement for this metric.
9.3.2. Packet Stream Generation
This section gives the details of the packet traffic which is the
basis for measurement. In IPPM metrics, this is called the Stream,
and can easily be described by providing the list of stream
parameters.
The ICMP metrics use a sending discipline called "SendOnRcv" or Send
On Receive. This is a modification of Section 3 of [RFC3432], which
prescribes the method for generating Periodic streams using
associated parameters as defined below for this description:
incT the nominal duration of inter-packet interval, first bit to
first bit
dT the duration of the interval for allowed sample start times
The incT stream parameter will be specified as a Run-time parameter,
and dT is not used in SendOnRcv.
A SendOnRcv sender behaves exactly like a Periodic stream generator
while all reply packets arrive with RTD < incT, and the inter-packet
interval will be constant.
If a reply packet arrives with RTD >= incT, then the inter-packet
interval for the next sending time is nominally RTD.
If a reply packet fails to arrive within Tmax, then the inter-packet
interval for the next sending time is nominally Tmax.
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If an immediate send on reply arrival is desired, then set incT=0.
9.3.3. Traffic Filtering (observation) Details
NA
9.3.4. Sampling Distribution
NA
9.3.5. Run-time Parameters and Data Format
Run-time Parameters are input factors that must be determined,
configured into the measurement system, and reported with the results
for the context to be complete.
Src the IP address of the host in the Src Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see Section 4 of [RFC6991])
Dst the IP address of the host in the Dst Role (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see section 4 of [RFC6991])
incT the nominal duration of inter-packet interval, first bit to
first bit, expressed in units of seconds, as a positive value of
type decimal64 with fraction digits = 4 (see section 9.3 of
[RFC6020]) and with resolution of 0.0001 seconds (0.1 ms).
T0 a time, the start of a measurement interval, (format "date-and-
time" as specified in Section 5.6 of [RFC3339], see also Section 3
of [RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a start time is unspecified
and Tf is to be interpreted as the Duration of the measurement
interval. The start time is controlled through other means.
Count The total count of ICMP Echo Requests to send, formatted as a
uint16, as per section 9.2 of [RFC6020].
(see the Packet Stream Generation section for additional Run-time
parameters)
9.3.6. Roles
Src launches each packet and waits for return transmissions from
Dst.
Dst waits for each packet from Src and sends a return packet to Src.
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9.4. Output
This category specifies all details of the Output of measurements
using the metric.
9.4.1. Type
See subsection titles in Reference Definition for Latency Types.
LossRatio -- the count of lost packets to total packets sent is the
basis for the loss ratio calculation as per Section 6.1 of [RFC6673].
9.4.2. Reference Definition
For all output types ---
T0 the start of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
Tf the end of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
TotalCount the count of packets actually sent by the Src to Dst
during the measurement interval.
For LossRatio -- the count of lost packets to total packets sent is
the basis for the loss ratio calculation as per Section 4.1 of
[RFC7680].
For each <statistic>, one of the following sub-sections apply:
9.4.2.1. Mean
The mean SHALL be calculated using the conditional distribution of
all packets with a finite value of Round-trip delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.2.2 of [RFC6049] for details on calculating this
statistic, and 4.2.3 of [RFC6049].
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Mean The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
9.4.2.2. Min
The minimum SHALL be calculated using the conditional distribution of
all packets with a finite value of Round-trip delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3.2 of [RFC6049] for details on calculating this
statistic, and 4.3.3 of [RFC6049].
Min The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
9.4.2.3. Max
The maximum SHALL be calculated using the conditional distribution of
all packets with a finite value of Round-trip delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3.2 of [RFC6049] for a closely related method for
calculating this statistic, and 4.3.3 of [RFC6049]. The formula is
as follows:
Max = (FiniteDelay [j])
such that for some index, j, where 1 <= j <= N
FiniteDelay[j] >= FiniteDelay[n] for all n
Max The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
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seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
9.4.3. Metric Units
The <statistic> of Round-trip Delay is expressed in seconds, where
<statistic> is one of:
o Mean
o Min
o Max
The Round-trip Loss Ratio is expressed as a percentage of lost
packets to total packets sent.
9.4.4. Calibration
Section 3.7.3 of [RFC7679] provides a means to quantify the
systematic and random errors of a time measurement. In-situ
calibration could be enabled with an internal loopback at the Source
host that includes as much of the measurement system as possible,
performs address manipulation as needed, and provides some form of
isolation (e.g., deterministic delay) to avoid send-receive interface
contention. Some portion of the random and systematic error can be
characterized this way.
When a measurement controller requests a calibration measurement, the
loopback is applied and the result is output in the same format as a
normal measurement with additional indication that it is a
calibration result.
Both internal loopback calibration and clock synchronization can be
used to estimate the available accuracy of the Output Metric Units.
For example, repeated loopback delay measurements will reveal the
portion of the Output result resolution which is the result of system
noise, and thus inaccurate.
9.5. Administrative items
9.5.1. Status
Current
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9.5.2. Requester
This RFC number
9.5.3. Revision
1.0
9.5.4. Revision Date
YYYY-MM-DD
9.6. Comments and Remarks
None
10. TCP Round-Trip Delay and Loss Registry Entries
This section specifies three initial registry entries for the Passive
assessment of TCP Round-Trip Delay (RTD) and another entry for TCP
Round-trip Loss Count.
IANA Note: Registry "Name" below specifies multiple registry entries,
whose output format varies according to the <statistic> element of
the name that specifies one form of statistical summary. There are
two additional metric names for Singleton RT Delay and Packet Count
metrics.
All column entries beside the ID, Name, Description, and Output
Reference Method categories are the same, thus this section proposes
four closely-related registry entries. As a result, IANA is also
asked to assign corresponding URLs to each Named Metric.
10.1. Summary
This category includes multiple indexes to the registry entry: the
element ID and metric name.
10.1.1. ID (Identifier)
IANA is asked to assign different numeric identifiers to each of the
four Named Metrics.
10.1.2. Name
RTDelay_Passive_IP-TCP_RFCXXXXsec10_Seconds_<statistic>
where <statistic> is one of:
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o Mean
o Min
o Max
RTDelay_Passive_IP-TCP-HS_RFCXXXXsec10_Seconds_Singleton
Note that a mid-point observer only has the opportunity to compose a
single RTDelay on the TCP Hand Shake.
RTLoss_Passive_IP-TCP_RFCXXXXsec10_Packet_Count
10.1.3. URI
URL: https://www.iana.org/ ... <name>
10.1.4. Description
RTDelay: This metric assesses the round-trip delay of TCP packets
constituting a single connection, exchanged between two hosts. We
consider the measurement of round-trip delay based on a single
Observation Point [RFC7011] somewhere in the network. The Output is
the Round-trip delay for all successfully exchanged packets expressed
as the <statistic> of their conditional delay distribution, where
<statistic> is one of:
o Mean
o Min
o Max
RTLoss: This metric assesses the estimated loss count for TCP packets
constituting a single connection, exchanged between two hosts. We
consider the measurement of round-trip delay based on a single
Observation Point [RFC7011] somewhere in the network. The Output is
the estimated Loss Count for the measurement interval.
10.1.5. Change Controller
IETF
10.1.6. Version (of Registry Format)
1.0
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10.2. Metric Definition
This category includes columns to prompt the entry of all necessary
details related to the metric definition, including the RFC reference
and values of input factors, called fixed parameters.
10.2.1. Reference Definitions
Although there is no RFC that describes passive measurement of Round-
Trip Delay, the parallel definition for Active measurement is:
Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip Delay
Metric for IPPM", RFC 2681, September 1999.
[RFC2681]
This metric definition uses the terms singleton and sample as defined
in Section 11 of [RFC2330]. (Section 2.4 of [RFC2681] provides the
reference definition of the singleton (single value) Round-trip delay
metric. Section 3.4 of [RFC2681] provides the reference definition
expanded to cover a multi-singleton sample.)
With the Observation Point [RFC7011] (OP) typically located between
the hosts participating in the TCP connection, the Round-trip Delay
metric requires two individual measurements between the OP and each
host, such that the Spatial Composition [RFC6049]of the measurements
yields a Round-trip Delay singleton (we are extending the composition
of one-way subpath delays to subpath round-trip delay).
Using the direction of TCP SYN transmission to anchor the
nomenclature, host A sends the SYN and host B replies with SYN-ACK
during connection establishment. The direction of SYN transfer is
considered the Forward direction of transmission, from A through OP
to B (Reverse is B through OP to A).
Traffic filters reduce the packet stream at the OP to a Qualified
bidirectional flow of packets.
In the definitions below, Corresponding Packets are transferred in
different directions and convey a common value in a TCP header field
that establishes correspondence (to the extent possible). Examples
may be found in the TCP timestamp fields.
For a real number, RTD_fwd, >> the Round-trip Delay in the Forward
direction from OP to host B at time T' is RTD_fwd << it is REQUIRED
that OP observed a Qualified Packet to host B at wire-time T', that
host B received that packet and sent a Corresponding Packet back to
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host A, and OP observed the Corresponding Packet at wire-time T' +
RTD_fwd.
For a real number, RTD_rev, >> the Round-trip Delay in the Reverse
direction from OP to host A at time T'' is RTD_rev << it is REQUIRED
that OP observed a Qualified Packet to host A at wire-time T'', that
host A received that packet and sent a Corresponding Packet back to
host B, and that OP observed the Corresponding Packet at wire-time
T'' + RTD_rev.
Ideally, the packet sent from host B to host A in both definitions
above SHOULD be the same packet (or, when measuring RTD_rev first,
the packet from host A to host B in both definitions should be the
same).
The REQUIRED Composition Function for a singleton of Round-trip Delay
at time T (where T is the earliest of T' and T'' above) is:
RTDelay = RTD_fwd + RTD_rev
Note that when OP is located at host A or host B, one of the terms
composing RTDelay will be zero or negligible.
When the Qualified and Corresponding Packets are a TCP-SYN and a TCP-
SYN-ACK, then RTD_fwd == RTD_HS_fwd.
When the Qualified and Corresponding Packets are a TCP-SYN-ACK and a
TCP-ACK, then RTD_rev == RTD_HS_rev.
The REQUIRED Composition Function for a singleton of Round-trip Delay
for the connection Hand Shake:
RTDelay_HS = RTD_HS_fwd + RTD_HS_rev
The definition of Round-trip Loss Count uses the nomenclature
developed above, based on observation of the TCP header sequence
numbers and storing the sequence number gaps observed. Packet Losses
can be inferred from:
o Out-of-order segments: TCP segments are transmitted with
monotonically increasing sequence numbers, but these segments may
be received out of order. Section 3 of [RFC4737] describes the
notion of "next expected" sequence numbers which can be adapted to
TCP segments (for the purpose of detecting reordered packets).
Observation of out-of-order segments indicates loss on the path
prior to the OP, and creates a gap.
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o Duplicate segments: Section 2 of [RFC5560] defines identical
packets and is suitable for evaluation of TCP packets to detect
duplication. Observation of duplicate segments *without a
corresponding gap* indicates loss on the path following the OP
(because they overlap part of the delivered sequence numbers
already observed at OP).
Each observation of an out-of-order or duplicate infers a singleton
of loss, but composition of Round-trip Loss Counts will be conducted
over a measurement interval which is synonymous with a single TCP
connection.
With the above observations in the Forward direction over a
measurement interval, the count of out-of-order and duplicate
segments is defined as RTL_fwd. Comparable observations in the
Reverse direction are defined as RTL_rev.
For a measurement interval (corresponding to a single TCP
connection), T0 to Tf, the REQUIRED Composition Function for a the
two single-direction counts of inferred loss is:
RTLoss = RTL_fwd + RTL_rev
10.2.2. Fixed Parameters
Traffic Filters:
o IPv4 header values:
* DSCP: set to 0
* Protocol: Set to 06 (TCP)
o IPv6 header values:
* DSCP: set to 0
* Hop Count: set to 255
* Next Header: set to 6 (TCP)
* Flow Label: set to zero
* Extension Headers: none
o TCP header values:
* Flags: ACK, SYN, FIN, set as required
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* Timestamp Option (TSopt): Set
+ Section 3.2 of [RFC7323]
10.3. Method of Measurement
This category includes columns for references to relevant sections of
the RFC(s) and any supplemental information needed to ensure an
unambiguous methods for implementations.
10.3.1. Reference Methods
The foundation methodology for this metric is defined in Section 4 of
[RFC7323] using the Timestamp Option with modifications that allow
application at a mid-path Observation Point (OP) [RFC7011]. Further
details and applicable heuristics were derived from [Strowes] and
[Trammell-14].
The Traffic Filter at the OP is configured to observe a single TCP
connection. When the SYN, SYN-ACK, ACK handshake occurs, it offers
the first opportunity to measure both RTD_fwd (on the SYN to SYN-ACK
pair) and RTD_rev (on the SYN-ACK to ACK pair). Label this singleton
of RTDelay as RTDelay_HS (composed using the forward and reverse
measurement pair). RTDelay_HS SHALL be treated separately from other
RTDelays on data-bearing packets and their ACKs. The RTDelay_HS
value MAY be used as a sanity check on other Composed values of
RTDelay.
For payload bearing packets, the OP measures the time interval
between observation of a packet with Sequence Number s, and the
corresponding ACK with same Sequence number. When the payload is
transferred from host A to host B, the observed interval is RTD_fwd.
Because many data transfers are unidirectional (say, in the Forward
direction from host A to host B), it is necessary to use pure ACK
packets with Timestamp (TSval) and their Timestamp value echo to
perform a RTD_rev measurement. The time interval between observation
of the ACK from B to A, and the corresponding packet with Timestamp
echo (TSecr) is the RTD_rev.
Delay Measurement Filtering Heuristics:
If Data payloads were transferred in both Forward and Reverse
directions, then the Round-Trip Time Measurement Rule in Section 4.1
of [RFC7323] could be applied. This rule essentially excludes any
measurement using a packet unless it makes progress in the transfer
(advances the left edge of the send window, consistent with
[Strowes]).
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A different heuristic from [Trammell-14] is to exclude any RTD_rev
that is larger than previously observed values. This would tend to
exclude Reverse measurements taken when the Application has no data
ready to send, because considerable time could be added to RTD_rev
from this source of error.
Note that the above Heuristic assumes that host A is sending data.
Host A expecting a download would mean that this heuristic should be
applied to RTD_fwd.
The statistic calculations to summarize the delay (RTDelay) SHALL be
performed on the conditional distribution, conditioned on successful
Forward and Reverse measurements which follow the Heuristics.
Method for Inferring Loss:
The OP tracks sequence numbers and stores gaps for each direction of
transmission, as well as the next-expected sequence number as in
[Trammell-14] and [RFC4737]. Loss is inferred from Out-of-order
segments and Duplicate segments.
Loss Measurement Filtering Heuristics:
[Trammell-14] adds a window of evaluation based on the RTDelay.
Distinguish Re-ordered from OOO due to loss, because sequence number
gap is filled during the same RTDelay window. Segments detected as
re-ordered according to [RFC4737] MUST reduce the Loss Count inferred
from Out-of-order segments.
Spurious (unneeded) retransmissions (observed as duplicates) can also
be reduced this way, as described in [Trammell-14].
Sources of Error:
The principal source of RTDelay error is the host processing time to
return a packet that defines the termination of a time interval. The
heuristics above intend to mitigate these errors by excluding
measurements where host processing time is a significant part of
RTD_fwd or RTD_rev.
A key source of RTLoss error is observation loss, described in
section 3 of [Trammell-14].
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10.3.2. Packet Stream Generation
NA
10.3.3. Traffic Filtering (observation) Details
The Fixed Parameters above give a portion of the Traffic Filter.
Other aspects will be supplied as Run-time Parameters (below).
10.3.4. Sampling Distribution
This metric requires a complete sample of all packets that qualify
according to the Traffic Filter criteria.
10.3.5. Run-time Parameters and Data Format
Run-time Parameters are input factors that must be determined,
configured into the measurement system, and reported with the results
for the context to be complete.
Src the IP address of the host in the host A Role (format ipv4-
address-no-zone value for IPv4, or ipv6-address-no-zone value for
IPv6, see Section 4 of [RFC6991])
Dst the IP address of the host in the host B (format ipv4-address-
no-zone value for IPv4, or ipv6-address-no-zone value for IPv6,
see section 4 of [RFC6991])
T0 a time, the start of a measurement interval, (format "date-and-
time" as specified in Section 5.6 of [RFC3339], see also Section 3
of [RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. When T0 is "all-zeros", a start time is unspecified
and Td is to be interpreted as the Duration of the measurement
interval. The start time is controlled through other means.
Td Optionally, the end of a measurement interval, (format "date-and-
time" as specified in Section 5.6 of [RFC3339], see also Section 3
of [RFC6991]), or the duration (see T0). The UTC Time Zone is
required by Section 6.1 of [RFC2330]. Alternatively, the end of
the measurement interval MAY be controlled by the measured
connection, where the second pair of FIN and ACK packets exchanged
between host A and B effectively ends the interval.
TTL or Hop Limit Set at desired value.
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10.3.6. Roles
host A launches the SYN packet to open the connection, and
synonymous with an IP address.
host B replies with the SYN-ACK packet to open the connection, and
synonymous with an IP address.
10.4. Output
This category specifies all details of the Output of measurements
using the metric.
10.4.1. Type
See subsection titles in Reference Definition for RTDelay Types.
For RTLoss -- the count of lost packets.
10.4.2. Reference Definition
For all output types ---
T0 the start of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330].
Tf the end of a measurement interval, (format "date-and-time" as
specified in Section 5.6 of [RFC3339], see also Section 3 of
[RFC6991]). The UTC Time Zone is required by Section 6.1 of
[RFC2330]. The end of the measurement interval MAY be controlled
by the measured connection, where the second pair of FIN and ACK
packets exchanged between host A and B effectively ends the
interval.
... ...
For RTDelay_HS -- the Round trip delay of the Handshake.
For RTLoss -- the count of lost packets.
For each <statistic>, one of the following sub-sections apply:
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10.4.2.1. Mean
The mean SHALL be calculated using the conditional distribution of
all packets with a finite value of Round-trip delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.2.2 of [RFC6049] for details on calculating this
statistic, and 4.2.3 of [RFC6049].
Mean The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
10.4.2.2. Min
The minimum SHALL be calculated using the conditional distribution of
all packets with a finite value of Round-trip delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
See section 4.3.2 of [RFC6049] for details on calculating this
statistic, and 4.3.3 of [RFC6049].
Min The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
10.4.2.3. Max
The maximum SHALL be calculated using the conditional distribution of
all packets with a finite value of Round-trip delay (undefined delays
are excluded), a single value as follows:
See section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and Section 5 of
[RFC6703] for background on this analysis choice.
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See section 4.3.2 of [RFC6049] for a closely related method for
calculating this statistic, and 4.3.3 of [RFC6049]. The formula is
as follows:
Max = (FiniteDelay [j])
such that for some index, j, where 1 <= j <= N
FiniteDelay[j] >= FiniteDelay[n] for all n
Max The time value of the result is expressed in units of seconds,
as a positive value of type decimal64 with fraction digits = 9
(see section 9.3 of [RFC6020]) with resolution of 0.000000001
seconds (1.0 ns), and with lossless conversion to/from the 64-bit
NTP timestamp as per section 6 of RFC [RFC5905]
10.4.3. Metric Units
The <statistic> of Round-trip Delay is expressed in seconds, where
<statistic> is one of:
o Mean
o Min
o Max
The Round-trip Delay of the Hand Shake is expressed in seconds.
The Round-trip Loss Count is expressed as a number of packets.
10.4.4. Calibration
Passive measurements at an OP could be calibrated against an active
measurement (with loss emulation) at host A or B, where the active
measurement represents the ground-truth.
10.5. Administrative items
10.5.1. Status
Current
10.5.2. Requester
This RFC number
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10.5.3. Revision
1.0
10.5.4. Revision Date
YYYY-MM-DD
10.6. Comments and Remarks
None.
11. Security Considerations
These registry entries represent no known implications for Internet
Security. Each RFC referenced above contains a Security
Considerations section. Further, the LMAP Framework [RFC7594]
provides both security and privacy considerations for measurements.
There are potential privacy considerations for observed traffic,
particularly for passive metrics in section 10. An attacker that
knows that its TCP connection is being measured can modify its
behavior to skew the measurement results.
12. IANA Considerations
IANA is requested to populate The Performance Metrics Registry
defined in [I-D.ietf-ippm-metric-registry] with the values defined in
sections 4 through 10.
See the IANA Considerations section of
[I-D.ietf-ippm-metric-registry] for additional requests and
considerations.
13. Acknowledgements
The authors thank Brian Trammell for suggesting the term "Run-time
Parameters", which led to the distinction between run-time and fixed
parameters implemented in this memo, for identifying the IPFIX metric
with Flow Key as an example, for suggesting the Passive TCP RTD
metric and supporting references, and for many other productive
suggestions. Thanks to Peter Koch, who provided several useful
suggestions for disambiguating successive DNS Queries in the DNS
Response time metric.
The authors also acknowledge the constructive reviews and helpful
suggestions from Barbara Stark, Juergen Schoenwaelder, Tim Carey,
Yaakov Stein, and participants in the LMAP working group. Thanks to
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Michelle Cotton for her early IANA reviews, and to Amanda Barber for
answering questions related to the presentation of the registry and
accessibility of the complete template via URL.
14. References
14.1. Normative References
[I-D.ietf-ippm-metric-registry]
Bagnulo, M., Claise, B., Eardley, P., and A. Morton,
"Registry for Performance Metrics", Internet Draft (work
in progress) draft-ietf-ippm-metric-registry, 2019.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <https://www.rfc-editor.org/info/rfc1035>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", RFC 2330,
DOI 10.17487/RFC2330, May 1998,
<https://www.rfc-editor.org/info/rfc2330>.
[RFC2681] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip
Delay Metric for IPPM", RFC 2681, DOI 10.17487/RFC2681,
September 1999, <https://www.rfc-editor.org/info/rfc2681>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation
Metric for IP Performance Metrics (IPPM)", RFC 3393,
DOI 10.17487/RFC3393, November 2002,
<https://www.rfc-editor.org/info/rfc3393>.
[RFC3432] Raisanen, V., Grotefeld, G., and A. Morton, "Network
performance measurement with periodic streams", RFC 3432,
DOI 10.17487/RFC3432, November 2002,
<https://www.rfc-editor.org/info/rfc3432>.
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[RFC4737] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,
S., and J. Perser, "Packet Reordering Metrics", RFC 4737,
DOI 10.17487/RFC4737, November 2006,
<https://www.rfc-editor.org/info/rfc4737>.
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
RFC 5357, DOI 10.17487/RFC5357, October 2008,
<https://www.rfc-editor.org/info/rfc5357>.
[RFC5481] Morton, A. and B. Claise, "Packet Delay Variation
Applicability Statement", RFC 5481, DOI 10.17487/RFC5481,
March 2009, <https://www.rfc-editor.org/info/rfc5481>.
[RFC5560] Uijterwaal, H., "A One-Way Packet Duplication Metric",
RFC 5560, DOI 10.17487/RFC5560, May 2009,
<https://www.rfc-editor.org/info/rfc5560>.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
<https://www.rfc-editor.org/info/rfc5905>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6049] Morton, A. and E. Stephan, "Spatial Composition of
Metrics", RFC 6049, DOI 10.17487/RFC6049, January 2011,
<https://www.rfc-editor.org/info/rfc6049>.
[RFC6673] Morton, A., "Round-Trip Packet Loss Metrics", RFC 6673,
DOI 10.17487/RFC6673, August 2012,
<https://www.rfc-editor.org/info/rfc6673>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
"Specification of the IP Flow Information Export (IPFIX)
Protocol for the Exchange of Flow Information", STD 77,
RFC 7011, DOI 10.17487/RFC7011, September 2013,
<https://www.rfc-editor.org/info/rfc7011>.
Morton, et al. Expires September 10, 2020 [Page 76]
Internet-Draft Initial Registry March 2020
[RFC7323] Borman, D., Braden, B., Jacobson, V., and R.
Scheffenegger, Ed., "TCP Extensions for High Performance",
RFC 7323, DOI 10.17487/RFC7323, September 2014,
<https://www.rfc-editor.org/info/rfc7323>.
[RFC7679] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
Ed., "A One-Way Delay Metric for IP Performance Metrics
(IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January
2016, <https://www.rfc-editor.org/info/rfc7679>.
[RFC7680] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
Ed., "A One-Way Loss Metric for IP Performance Metrics
(IPPM)", STD 82, RFC 7680, DOI 10.17487/RFC7680, January
2016, <https://www.rfc-editor.org/info/rfc7680>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[Strowes] Strowes, S., "Passively Measuring TCP Round Trip Times,
Communications of the ACM, Vol. 56 No. 10, Pages 57-64",
September 2013.
[Trammell-14]
Trammell, B., "Inline Data Integrity Signals for Passive
Measurement, In: Dainotti A., Mahanti A., Uhlig S. (eds)
Traffic Monitoring and Analysis. TMA 2014. Lecture Notes
in Computer Science, vol 8406. Springer, Berlin,
Heidelberg https://link.springer.com/
chapter/10.1007/978-3-642-54999-1_2", March 2014.
14.2. Informative References
[RFC1242] Bradner, S., "Benchmarking Terminology for Network
Interconnection Devices", RFC 1242, DOI 10.17487/RFC1242,
July 1991, <https://www.rfc-editor.org/info/rfc1242>.
[RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New
Performance Metric Development", BCP 170, RFC 6390,
DOI 10.17487/RFC6390, October 2011,
<https://www.rfc-editor.org/info/rfc6390>.
[RFC6703] Morton, A., Ramachandran, G., and G. Maguluri, "Reporting
IP Network Performance Metrics: Different Points of View",
RFC 6703, DOI 10.17487/RFC6703, August 2012,
<https://www.rfc-editor.org/info/rfc6703>.
Morton, et al. Expires September 10, 2020 [Page 77]
Internet-Draft Initial Registry March 2020
[RFC7594] Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
Aitken, P., and A. Akhter, "A Framework for Large-Scale
Measurement of Broadband Performance (LMAP)", RFC 7594,
DOI 10.17487/RFC7594, September 2015,
<https://www.rfc-editor.org/info/rfc7594>.
Authors' Addresses
Al Morton
AT&T Labs
200 Laurel Avenue South
Middletown,, NJ 07748
USA
Phone: +1 732 420 1571
Fax: +1 732 368 1192
Email: acmorton@att.com
Marcelo Bagnulo
Universidad Carlos III de
Madrid
Av. Universidad 30
Leganes, Madrid 28911
SPAIN
Phone: 34 91 6249500
Email: marcelo@it.uc3m.es
URI: http://www.it.uc3m.es
Philip Eardley
BT
Adastral Park, Martlesham Heath
Ipswich
ENGLAND
Email: philip.eardley@bt.com
Kevin D'Souza
AT&T Labs
200 Laurel Avenue South
Middletown,, NJ 07748
USA
Phone: +1 732 420 xxxx
Email: kld@att.com
Morton, et al. Expires September 10, 2020 [Page 78]
