Internet DRAFT - draft-mornuley-ippm-registry-active
draft-mornuley-ippm-registry-active
Network Working Group A. Morton
Internet-Draft AT&T Labs
Intended status: Standards Track M. Bagnulo
Expires: August 17, 2014 UC3M
P. Eardley
BT
February 13, 2014
Active Performance Metric Sub-Registry
draft-mornuley-ippm-registry-active-00
Abstract
This memo defines the Active Performance Metrics sub-registry of the
Performance Metric Registry. This sub-registry will contain Active
Performance Metrics, especially those defined in RFCs prepared in the
IP Performance Metrics (IPPM) Working Group of the IETF, and possibly
applicable to other IETF metrics. Three aspects make IPPM metric
registration difficult: (1) Use of the Type-P notion to allow users
to specify their own packet types. (2) Use of flexible input
variables, called Parameters in IPPM definitions, some of which
determine the quantity measured and others of which should not be
specified until execution of the measurement. (3) Allowing
flexibility in choice of statistics to summarize the results on a
stream of measurement packets.
This memo proposes a way to organize registry entries into columns
that are well-defined, permitting consistent development of entries
over time (a column may marked NA if it is not applicable for that
metric). The design is intended to foster development of registry
entries based on existing reference RFCs, whilst each column serves
as a check-list item to avoid omissions during the registration
process. Every entry in the registry, before IANA action, requires
Expert review as defined by concurrent IETF work in progress
"Registry for Performance Metrics" (draft-manyfolks-ippm-metric-
registry).
The document contains two examples: a registry entry for an active
Performance Metric entry based on RFC3393 and RFC5481, and a registry
entry for an end-point Performance Metric based on RFC 7003. The
examples are for Informational purposes and do not create any entry
in the IANA registry.
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Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 17, 2014.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Background and Motivation . . . . . . . . . . . . . . . . 5
2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Registry Categories and Columns . . . . . . . . . . . . . . . 7
3.1. Common Registry Indexes and Information . . . . . . . . . 8
3.1.1. Identifier . . . . . . . . . . . . . . . . . . . . . 8
3.1.2. Name . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.3. Status . . . . . . . . . . . . . . . . . . . . . . . 8
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3.1.4. Requester . . . . . . . . . . . . . . . . . . . . . . 9
3.1.5. Revision . . . . . . . . . . . . . . . . . . . . . . 9
3.1.6. Revision Date . . . . . . . . . . . . . . . . . . . . 9
3.1.7. Description . . . . . . . . . . . . . . . . . . . . . 9
3.1.8. Reference Specification(s) . . . . . . . . . . . . . 9
3.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 9
3.2.1. Reference Definition . . . . . . . . . . . . . . . . 9
3.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 9
3.3. Method of Measurement . . . . . . . . . . . . . . . . . . 10
3.3.1. Reference Method . . . . . . . . . . . . . . . . . . 10
3.3.2. Stream Type and Stream Parameters . . . . . . . . . . 10
3.3.3. Output Type and Data Format . . . . . . . . . . . . . 11
3.3.4. Metric Units . . . . . . . . . . . . . . . . . . . . 11
3.3.5. Run-time Parameters and Data Format . . . . . . . . . 11
3.4. Comments and Remarks . . . . . . . . . . . . . . . . . . 12
4. Example IPPM Active Registry Entry . . . . . . . . . . . . . 12
4.1. Registry Indexes . . . . . . . . . . . . . . . . . . . . 12
4.1.1. Element ID . . . . . . . . . . . . . . . . . . . . . 12
4.1.2. Metric Name . . . . . . . . . . . . . . . . . . . . . 12
4.1.3. Metric Description . . . . . . . . . . . . . . . . . 12
4.1.4. Other Info Columns not provided in Example . . . . . 13
4.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 13
4.2.1. Reference Definition . . . . . . . . . . . . . . . . 13
4.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 13
4.3. Method of Measurement . . . . . . . . . . . . . . . . . . 13
4.3.1. Reference Method . . . . . . . . . . . . . . . . . . 13
4.3.2. Stream Type and Stream Parameters . . . . . . . . . . 13
4.3.3. Output Type and Data Format . . . . . . . . . . . . . 14
4.3.4. Metric Units . . . . . . . . . . . . . . . . . . . . 14
4.3.5. Run-time Parameters and Data Format . . . . . . . . . 14
4.4. Comments and Remarks . . . . . . . . . . . . . . . . . . 15
5. Example RTCP-XR Registry Entry . . . . . . . . . . . . . . . 15
5.1. Registry Indexes . . . . . . . . . . . . . . . . . . . . 15
5.1.1. Element ID . . . . . . . . . . . . . . . . . . . . . 16
5.1.2. Metric Name . . . . . . . . . . . . . . . . . . . . . 16
5.1.3. Metric Description . . . . . . . . . . . . . . . . . 16
5.1.4. Other Info Columns not provided in Example . . . . . 16
5.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 16
5.2.1. Reference Definition . . . . . . . . . . . . . . . . 16
5.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 16
5.3. Method of Measurement . . . . . . . . . . . . . . . . . . 17
5.3.1. Reference Method . . . . . . . . . . . . . . . . . . 17
5.3.2. Stream Type and Stream Parameters . . . . . . . . . . 17
5.3.3. Output Type and Data Format . . . . . . . . . . . . . 18
5.3.4. Metric Units . . . . . . . . . . . . . . . . . . . . 18
5.3.5. Run-time Parameters and Data Format . . . . . . . . . 18
5.4. Comments and Remarks . . . . . . . . . . . . . . . . . . 20
6. Example BLANK Registry Entry . . . . . . . . . . . . . . . . 20
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6.1. Registry Indexes . . . . . . . . . . . . . . . . . . . . 20
6.1.1. Element ID . . . . . . . . . . . . . . . . . . . . . 20
6.1.2. Metric Name . . . . . . . . . . . . . . . . . . . . . 20
6.1.3. Metric Description . . . . . . . . . . . . . . . . . 20
6.1.4. Other Info Columns not provided in Example . . . . . 20
6.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 20
6.2.1. Reference Definition . . . . . . . . . . . . . . . . 20
6.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 20
6.3. Method of Measurement . . . . . . . . . . . . . . . . . . 21
6.3.1. Reference Method . . . . . . . . . . . . . . . . . . 21
6.3.2. Stream Type and Stream Parameters . . . . . . . . . . 21
6.3.3. Output Type and Data Format . . . . . . . . . . . . . 21
6.3.4. Metric Units . . . . . . . . . . . . . . . . . . . . 21
6.3.5. Run-time Parameters and Data Format . . . . . . . . . 21
6.4. Comments and Remarks . . . . . . . . . . . . . . . . . . 22
7. Security Considerations . . . . . . . . . . . . . . . . . . . 22
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 23
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
10.1. Normative References . . . . . . . . . . . . . . . . . . 23
10.2. Informative References . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction
[ISSUES
1. REAL-TIME OR INPUT PARAMETER [CONSISTENT WITH REGISTRY I-D]
closed - just Parameter
2. CHANGED STREAM PARAMETER TO STREAM INPUT PARAMETER I didn't find
any instances of this change - closed
3. I PREFER KEEPING THE CATEGORY-COLUMN HIERARCHY - ok we keep it
4. RATHER THAN BLANK COLUMNS, SHOULD WE HAVE 'NOT APPLICABLE' [MAYBE
EVEN IANA REGISTERED??] sounds good to Al, used NA.
5. THE EXAMPLES ARE INFORMATIONAL NOT STANDARDS TRACK yes of course
- -Closed.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Note: Efforts to synchronize terminology with
[I-D.manyfolks-ippm-metric-registry] will likely be incomplete until
both drafts are stable.
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This memo defines the Active Performance Metrics sub-registry of the
Performance Metric Registry. This sub-registry will contain Active
Performance Metrics, especially those defined in RFCs prepared in the
IP Performance Metrics (IPPM) Working Group of the IETF, according to
their framework [RFC2330]. Three aspects make IPPM metric
registration difficult: (1) Use of the Type-P notion to allow users
to specify their own packet types. (2) Use of Flexible input
variables, called Parameters in IPPM definitions, some which
determine the quantity measured and others which should not be
specified until execution of the measurement. (3) Allowing
flexibility in choice of statistics to summarize the results on a
stream of measurement packets. This memo uses terms and definitions
from the IPPM literature, primarily [RFC2330], and the reader is
assumed familiar with them or may refer questions there as necessary.
This sub-registry is part of the Performance Metric Registry
[I-D.manyfolks-ippm-metric-registry] which specifies that all sub-
registries must contain at least the following fields: the
identifier, the name, the status, the requester, the revision, the
revision date, the description for each entry, and the reference
specifications used as the foundation for the Registered Performance
Metric (see [I-D.manyfolks-ippm-metric-registry]).
Although there are several standard templates for organizing
specifications of performance metrics (see [RFC2679] 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 was intended to become the basis for the columns of an
IETF-wide registry of metrics. As we examined the aspects of metric
specifications which need to be registered, it was clear that none of
the existing metric templates fully satisfies the particular needs of
a registry.
1.1. Background and Motivation
One clear motivation for having such a registry is to allow a
controller to request a measurement agent to execute a measurement
using a specific metric (see [I-D.ietf-lmap-framework]). Such a
request can be performed using any control protocol that refers to
the value assigned to the specific metric in the registry.
Similarly, the measurement agent can report the results of the
measurement and by referring to the metric value it can unequivocally
identify the metric that the results correspond to.
There was a previous attempt to define a metric registry RFC 4148
[RFC4148]. However, it was obsoleted by RFC 6248 [RFC6248] because
it was "found to be insufficiently detailed to uniquely identify IPPM
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metrics... [there was too much] variability possible when
characterizing a metric exactly" which led to the RFC4148 registry
having "very few users, if any".
Our approach learns from this by tightly defining each entry in the
registry with only a few parameters open, if any. The idea is that
entries in the registry represent different measurement methods.
Each may require run-time parameters to set factors like source and
destination addresses, which do not change the fundamental nature of
the measurement and can be set just before measurement execution.
The downside of this approach is that it could result in a large
number of entries in the registry. We believe that less is more in
this context - it is better to have a reduced set of useful metrics
rather than a large set of metrics with questionable usefulness.
Therefore it is required for all registries within the Performance
Metric Registry (see [I-D.manyfolks-ippm-metric-registry]) that the
registry only includes commonly used metrics that are well defined;
hence we require expert review policies for the approval and
assignment of entries in this sub-registry.
There are several side benefits of having a registry with well-chosen
entries. First, the registry could serve as an inventory of useful
and used metrics that are normally supported by different
implementations of measurement agents. Second, the results of the
metrics would be comparable even if they are performed by different
implementations and in different networks, as the metric and method
is unambiguously defined.
The registry constitutes a key component of a 'Characterization
Plan'. It describes various factors that need to be set by the party
controlling the measurements, for example: specific values for the
parameters associated with the selected registry entry (for instance,
source and destination addresses); and how often the measurement is
made. The Characterization Plan determines the individual
Measurement Tasks which Measurement Agents will be instructed to do
and which they then execute autonomously.
Measurement Instructions might look something like: "Dear measurement
agent: Please start test DNS(example.com) and RTT(server.com,150)
every day at 2000 GMT. Run the DNS test 5 times and the RTT test 50
times. Do that when the network is idle. Generate both raw results
and 99th percentile mean. Send measurement results to collector.com
in IPFIX format". The Characterization Plan depends on the
requirements of the controlling party. For instance the broadband
consumer might want a one-off measurement made immediately to one
specific server; a regulator might want the same measurement made
once a day until further notice to the 'top 10' servers; whilst an
operator might want a varying series of tests (some of which will be
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beyond those defined in an IETF registry) as determined from time to
time by their operational support system. While the registries
defined in this document help to define the Characterization Plan,
its full specification falls outside the scope of this document, and
other IETF work as currently chartered.
2. Scope
[I-D.manyfolks-ippm-metric-registry] defines the overall structure
for a Performance Metric Registry and provides guidance for defining
a sub registry.
This document defines the Active Performance Metrics Sub-registry;
active metrics are those where the packets measured have been
specially generated for the purpose.
A row in the registry corresponds to one Registered Performance
Metric, with entries in the various columns specifying the metric.
Section 3 defines the columns for a Registered Active Performance
Metric.
As discussed in [I-D.manyfolks-ippm-metric-registry], each entry
(row) must be tightly defined; the definition must leave open only a
few parameters that do not change the fundamental nature of the
measurement (such as source and destination addresses), and so
promotes comparable results across independent implementations.
Also, each registered entry must be based on existing reference RFCs
(or other standards) for performance metrics, and must be
operationally useful and have significant industry interest. This is
ensured by expert review for every entry before IANA action.
3. Registry Categories and Columns
This section defines the categories and columns of the registry.
Below, categories are described at the 3.x heading level, and columns
are at the 3.x.y heading level. The Figure below illustrates this
organization. An entry (row) therefore gives a complete description
of a Registered Metric.
Each column serves as a check-list item and helps to avoid omissions
during registration and expert review. In some cases an entry (row)
may have some columns without specific entries, marked Not Applicable
(NA).
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Registry Categories and Columns, shown as
Category
------------------
Column | Column |
Common Registry Indexes and Information
---------------------------------------------------------------------
ID | Name | Status |Request | Rev| Rev.Date | Description | Ref Spec|
Metric Definition
-----------------------------------------
Reference Definition | Fixed Parameters |
Method of Measurement
----------------------------------------------------------------
Reference Method | Stream Type | Output | Output | Run-time |
| and Parameters | Type | Units | Param
Comments and Remarks
--------------------
3.1. Common Registry Indexes and Information
This category has multiple indexes to each registry entry. It is
defined in [I-D.manyfolks-ippm-metric-registry]:
3.1.1. Identifier
Defined in [I-D.manyfolks-ippm-metric-registry]. In order to have
the document self contained, we could copy the definition from
[I-D.manyfolks-ippm-metric-registry] here, but i guess we should do
that once the definition in [I-D.manyfolks-ippm-metric-registry] is
stable.
3.1.2. Name
Defined in [I-D.manyfolks-ippm-metric-registry], same comment than
above.
3.1.3. Status
Defined in [I-D.manyfolks-ippm-metric-registry], same comment than
above.
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3.1.4. Requester
Defined in [I-D.manyfolks-ippm-metric-registry], same comment than
above.
3.1.5. Revision
Defined in [I-D.manyfolks-ippm-metric-registry], same comment than
above.
3.1.6. Revision Date
Defined in [I-D.manyfolks-ippm-metric-registry], same comment than
above.
3.1.7. Description
Defined in [I-D.manyfolks-ippm-metric-registry], same comment as the
previous.
3.1.8. Reference Specification(s)
Defined in [I-D.manyfolks-ippm-metric-registry], same comment as the
previous.
3.2. Metric Definition
This category includes columns to prompt all necessary details
related to the metric definition, including the RFC reference and
values of input factors, called fixed parameters, which are left open
in the RFC but have a particular value defined by the performance
metric.
3.2.1. Reference Definition
This entry provides references to relevant sections of the RFC(s)
defining the metric, as well as any supplemental information needed
to ensure an unambiguous definition for implementations.
3.2.2. Fixed Parameters
Fixed Parameters are input factors whose value must be specified in
the Registry. The measurement system uses these values.
Where referenced metrics supply a list of Parameters as part of their
descriptive template, a sub-set of the Parameters will be designated
as Fixed Parameters. For example, Fixed Parameters determine most or
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all of the IPPM Framework convention "packets of Type-P" as described
in [RFC2330], such as transport protocol, payload length, TTL, etc.
A Parameter which is Fixed for one Registry entry may be designated
as a Run-time Parameter for another Registry entry.
3.3. 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 method for implementations.
3.3.1. Reference Method
This entry provides references to relevant sections of the RFC(s)
describing the method of measurement, as well as any supplemental
information needed to ensure unambiguous interpretation for
implementations referring to the RFC text.
3.3.2. Stream Type and Stream Parameters
Principally, two different streams are used in IPPM metrics, Poisson
distributed as described in [RFC2330] and Periodic as described in
[RFC3432]. Both Poisson and Periodic have their own unique
parameters, and the relevant set of values is specified in this
column.
Each entry for this column contains the following information:
o Value: The name of the packet stream scheduling discipline
o Stream Parameters: The values and formats of input factors for
each type of stream. For example, the average packet rate and
distribution truncation value for streams with Poisson-distributed
inter-packet sending times.
o Reference: the specification where the stream is defined
The simplest example of stream specification is Singleton scheduling,
where a single atomic measurement is conducted. Each atomic
measurement could consist of sending a single packet (such as a DNS
request) or sending several packets (for example, to request a
webpage). Other streams support a series of atomic measurements in a
"sample", with a schedule defining the timing between each
transmitted packet and subsequent measurement.
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3.3.3. Output Type and Data Format
For entries which involve a stream and many singleton measurements, a
statistic may be specified in this column to summarize the results to
a single value. If the complete set of measured singletons is
output, this will be specified here.
Some metrics embed one specific statistic in the reference metric
definition, while others allow several output types or statistics.
Each entry in the output type column contains the following
information:
o Value: The name of the output type
o Data Format: provided to simplify the communication with
collection systems and implementation of measurement devices.
o Reference: the specification where the output type is defined
The output type defines the type of result that the metric produces.
It can be the raw results or it can be some form of statistic. The
specification of the output type must define the format of the
output. In some systems, format specifications will simplify both
measurement implementation and collection/storage tasks. Note that
if two different statistics are required from a single measurement
(for example, both "Xth percentile mean" and "Raw"), then a new
output type must be defined ("Xth percentile mean AND Raw").
3.3.4. Metric Units
The measured results must be expressed using some standard dimension
or units of measure. This column provides the units.
When a sample of singletons (see [RFC2330] for definitions of these
terms) is collected, this entry will specify the units for each
measured value.
3.3.5. 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. However, the values of these
parameters is not specified in the Registry, rather these parameters
are listed as an aid to the measurement system implementor or user
(they must be left as variables, and supplied on execution).
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Where metrics supply a list of Parameters as part of their
descriptive template, a sub-set of the Parameters will be designated
as Run-Time Parameters.
The Data Format of each Run-time Parameter SHALL be specified in this
column, to simplify the control and implementation of measurement
devices.
Examples of Run-time Parameters include IP addresses, measurement
point designations, start times and end times for measurement, and
other information essential to the method of measurement.
3.4. Comments and Remarks
Besides providing additional details which do not appear in other
categories, this open Category (single column) allows for unforeseen
issues to be addressed by simply updating this Informational entry.
4. Example IPPM Active Registry Entry
This section is Informational.
This section gives an example registry entry for the active metric
described in [RFC3393], on Packet Delay Variation.
4.1. Registry Indexes
This category includes multiple indexes to the registry entries, the
element ID and metric name.
4.1.1. Element ID
An integer having enough digits to uniquely identify each entry in
the Registry.
4.1.2. Metric Name
A metric naming convention is TBD.
One possibility based on IPPM's framework is:
Act_IP-UDP-One-way-pdv-95th-percentile-Poisson
4.1.3. Metric Description
An assessment of packet delay variation with respect to the minimum
delay observed on the stream.
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4.1.4. Other Info Columns not provided in Example
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
See sections 2.4 and 3.4 of [RFC3393]. Singleton delay differences
measured are referred to by the variable name "ddT".
4.2.2. Fixed Parameters
Since the metric's reference supplies a list of Parameters as part of
its descriptive template, a sub-set of the Parameters have been
designated as designated as Fixed Parameters for this entry.
o F, a selection function defining unambiguously the packets from
the stream selected for the metric. See section 4.2 of [RFC5481]
for the PDV form.
o L, a packet length in bits. L = 200 bits.
o Tmax, a maximum waiting time for packets to arrive at Dst, set
sufficiently long to disambiguate packets with long delays from
packets that are discarded (lost). Tmax = 3 seconds.
o Type-P, as defined in [RFC2330], which includes any field that may
affect a packet's treatment as it traverses the network. The
packets are IP/UDP, with DSCP = 0 (BE).
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
See section 2.6 and 3.6 of [RFC3393] for singleton elements.
4.3.2. Stream Type and Stream Parameters
Poisson distributed as described in [RFC2330], with the following
Parameters.
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o lambda, a rate in reciprocal seconds (for Poisson Streams).
lambda = 1 packet per second
o Upper limit on Poisson distribution (values above this limit will
be clipped and set to the limit value). Upper limit = 30 seconds.
4.3.3. Output Type and Data Format
See section 4.3 of [RFC3393] for details on the percentile statistic.
The percentile = 95.
Data format is a 32-bit unsigned floating point value.
Individual results (singletons) should be represented by the
following triple
o T1 and T2, times as described below in the Run-time parameters
section.
o ddT as defined in section 2.4 of [RFC3393]
if needed. The result format for ddT is *similar to* the short
format in [RFC5905] (32 bits) and is as follows: the first 16 bits
represent the *signed* integer number of seconds; the next 16 bits
represent the fractional part of a second.
4.3.4. Metric Units
See section 3.3 of [RFC3393] for singleton elements.
[RFC2330] recommends that when a time is given, it will be expressed
in UTC.
The timestamp format (for T, Tf, etc.) is the same as in [RFC5905]
(64 bits) and is as follows: the first 32 bits represent the unsigned
integer number of seconds elapsed since 0h on 1 January 1900; the
next 32 bits represent the fractional part of a second that has
elapsed since then.
4.3.5. Run-time Parameters and Data Format
Since the metric's reference supplies a list of Parameters as part of
its descriptive template, a sub-set of the Parameters have been
designated as Run-Time Parameters for this entry. In related
registry entries, some of the parameters below may be designated as
Fixed Parameters instead.
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o Src, the IP address of a host (32-bit value for IPv4, 128-bit
value for IPv6)
o Dst, the IP address of a host (32-bit value for IPv4, 128-bit
value for IPv6)
o T, a time (start of test interval, 128-bit NTP Date Format, see
section 6 of [RFC5905])
o Tf, a time (end of test interval, 128-bit NTP Date Format, see
section 6 of [RFC5905])
o T1, the wire time of the first packet in a pair, measured at
MP(Src) as it leaves for Dst (64-bit NTP Timestamp Format, see
section 6 of [RFC5905]).
o T2, the wire time of the second packet in a pair, measured at
MP(Src) as it leaves for Dst (64-bit NTP Timestamp Format, see
section 6 of [RFC5905]).
o I(i),I(i+1), i >=0, pairs of times which mark the beginning and
ending of the intervals in which the packet stream from which the
measurement is taken occurs. Here, I(0) = T0 and assuming that n
is the largest index, I(n) = Tf (pairs of 64-bit NTP Timestamp
Format, see section 6 of [RFC5905]).
4.4. 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.
5. Example RTCP-XR Registry Entry
This section is Informational.
This section gives an example registry entry for the end-point metric
described in RFC 7003 [RFC7003], for RTCP-XR Burst/Gap Discard Metric
reporting.
5.1. Registry Indexes
This category includes multiple indexes to the registry entries, the
element ID and metric name.
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5.1.1. Element ID
An integer having enough digits to uniquely identify each entry in
the Registry.
5.1.2. Metric Name
A metric naming convention is TBD.
5.1.3. Metric Description
TBD.
5.1.4. Other Info Columns not provided in Example
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. Section 3.2 of
[RFC7003] provides the reference information for this category.
5.2.1. Reference Definition
Packets Discarded in Bursts:
The total number of packets discarded during discard bursts. The
measured value is unsigned value. If the measured value exceeds
0xFFFFFD, the value 0xFFFFFE MUST be reported to indicate an over-
range measurement. If the measurement is unavailable, the value
0xFFFFFF MUST be reported.
5.2.2. Fixed Parameters
Fixed Parameters are input factors that must be determined and
embedded in the measurement system for use when needed. The values
of these parameters is specified in the Registry.
Threshold: 8 bits, set to value = 3 packets.
The Threshold is equivalent to Gmin in [RFC3611], i.e., the number of
successive packets that must not be discarded prior to and following
a discard packet in order for this discarded packet to be regarded as
part of a gap. Note that the Threshold is set in accordance with the
Gmin calculation defined in Section 4.7.2 of [RFC3611].
Interval Metric flag: 2 bits, set to value 11=Cumulative Duration
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This field is used to indicate whether the burst/gap discard metrics
are Sampled, Interval, or Cumulative metrics [RFC6792]:
I=10: Interval Duration - the reported value applies to the most
recent measurement interval duration between successive metrics
reports.
I=11: Cumulative Duration - the reported value applies to the
accumulation period characteristic of cumulative measurements.
Senders MUST NOT use the values I=00 or I=01.
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. For the Burst/Gap Discard
Metric, it appears that the only guidance on methods of measurement
is in Section 3.0 of [RFC7003] and its supporting references.
Relevant information is repeated below, although there appears to be
no section titled "Method of Measurement" in [RFC7003].
5.3.1. Reference Method
Metrics in this block report on burst/gap discard in the stream
arriving at the RTP system. Measurements of these metrics are made
at the receiving end of the RTP stream. Instances of this metrics
block use the synchronization source (SSRC) to refer to the separate
auxiliary Measurement Information Block [RFC6776], which describes
measurement periods in use (see [RFC6776], Section 4.2).
This metrics block relies on the measurement period in the
Measurement Information Block indicating the span of the report.
Senders MUST send this block in the same compound RTCP packet as the
Measurement Information Block. Receivers MUST verify that the
measurement period is received in the same compound RTCP packet as
this metrics block. If not, this metrics block MUST be discarded.
5.3.2. Stream Type and Stream Parameters
Since RTCP-XR Measurements are conducted on live RTP traffic, the
complete description of the stream is contained in SDP messages that
proceed the establishment of a compatible stream between two or more
communicating hosts. See Run-time Parameters, below.
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5.3.3. Output Type and Data Format
The output type defines the type of result that the metric produces.
o Value: Packets Discarded in Bursts
o Data Format: 24 bits
o Reference: Section 3.2 of [RFC7003]
5.3.4. Metric Units
The measured results are apparently expressed in packets, although
there is no section of [RFC7003] titled "Metric Units".
5.3.5. 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. However, the values of these
parameters is not specified in the Registry, rather these parameters
are listed as an aid to the measurement system implementor or user
(they must be left as variables, and supplied on execution).
The Data Format of each Run-time Parameter SHALL be specified in this
column, to simplify the control and implementation of measurement
devices.
SSRC of Source: 32 bits As defined in Section 4.1 of [RFC3611].
SDP Parameters: As defined in [RFC4566]
Session description v= (protocol version number, currently only 0)
o= (originator and session identifier : username, id, version number,
network address)
s= (session name : mandatory with at least one UTF-8-encoded
character)
i=* (session title or short information) u=* (URI of description)
e=* (zero or more email address with optional name of contacts)
p=* (zero or more phone number with optional name of contacts)
c=* (connection information--not required if included in all media)
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b=* (zero or more bandwidth information lines) One or more Time
descriptions ("t=" and "r=" lines; see below)
z=* (time zone adjustments)
k=* (encryption key)
a=* (zero or more session attribute lines)
Zero or more Media descriptions (each one starting by an "m=" line;
see below)
m= (media name and transport address)
i=* (media title or information field)
c=* (connection information -- optional if included at session level)
b=* (zero or more bandwidth information lines)
k=* (encryption key)
a=* (zero or more media attribute lines -- overriding the Session
attribute lines)
An example Run-time SDP description follows:
v=0
o=jdoe 2890844526 2890842807 IN IP4 192.0.2.5
s=SDP Seminar i=A Seminar on the session description protocol
u=http://www.example.com/seminars/sdp.pdf e=j.doe@example.com (Jane
Doe)
c=IN IP4 233.252.0.12/127
t=2873397496 2873404696
a=recvonly
m=audio 49170 RTP/AVP 0
m=video 51372 RTP/AVP 99
a=rtpmap:99 h263-1998/90000
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5.4. Comments and Remarks
TBD.
6. Example BLANK Registry Entry
This section is Informational. (?)
This section gives an example registry entry for the <type of metric
and specification reference> .
6.1. Registry Indexes
This category includes multiple indexes to the registry entries, the
element ID and metric name.
6.1.1. Element ID
An integer having enough digits to uniquely identify each entry in
the Registry.
6.1.2. Metric Name
A metric naming convention is TBD.
6.1.3. Metric Description
A metric Description is TBD.
6.1.4. Other Info Columns not provided in Example
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.
<possible section reference>.
6.2.1. Reference Definition
6.2.2. Fixed Parameters
Fixed Parameters are input factors that must be determined and
embedded in the measurement system for use when needed. The values
of these parameters is specified in the Registry.
<list fixed parameters>
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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
For <metric>.
<section reference>
6.3.2. Stream Type and Stream Parameters
<list of stream parameters>.
<references>
6.3.3. Output Type and Data Format
The output type defines the type of result that the metric produces.
o Value:
o Data Format: (There may be some precedent to follow here, but
otherwise use 64-bit NTP Timestamp Format, see section 6 of
[RFC5905]).
o Reference: <section reference>
6.3.4. Metric Units
The measured results are expressed in <units>,
<section reference>.
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.
<list of run-time parameters>
<reference(s)>.
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6.4. Comments and Remarks
Additional (Informational) details for this entry
7. Security Considerations
This registry has no known implications on Internet Security.
8. IANA Considerations
IANA is requested to create The Active Performance Metric Sub-
registry within the Performance Metric Registry defined in
[I-D.manyfolks-ippm-metric-registry]. The Sub-registry will contain
the following categories and (bullet) columns, (as defined in section
3 above):
Common Registry Indexes and Info
o Identifier
o Name
o Status
o Requester
o Revision
o Revision Date
o Description
o Reference Specification(s)
Metric Definition
o Reference Definition
o Fixed Parameters
Method of Measurement
o Reference Method
o Stream Type and Parameters
o Output type and Data format
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o Metric Units
o Run-time Parameters
Comments and Remarks
9. 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, and the IPFIX metric with Flow
Key as an example.
10. References
10.1. Normative References
[I-D.manyfolks-ippm-metric-registry]
Bagnulo, M., Claise, B., Eardley, P., and A. Morton,
"Registry for Performance Metrics", Internet Draft (work
in progress) draft-manyfolks-ippm-metric-registry, 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", RFC 2330, May
1998.
[RFC2679] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way
Delay Metric for IPPM", RFC 2679, September 1999.
[RFC2680] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way
Packet Loss Metric for IPPM", RFC 2680, September 1999.
[RFC2681] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip
Delay Metric for IPPM", RFC 2681, September 1999.
[RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation
Metric for IP Performance Metrics (IPPM)", RFC 3393,
November 2002.
[RFC3432] Raisanen, V., Grotefeld, G., and A. Morton, "Network
performance measurement with periodic streams", RFC 3432,
November 2002.
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[RFC4737] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,
S., and J. Perser, "Packet Reordering Metrics", RFC 4737,
November 2006.
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
RFC 5357, October 2008.
[RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network
Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, June 2010.
10.2. Informative References
[Brow00] Brownlee, N., "Packet Matching for NeTraMet
Distributions", March 2000.
[I-D.ietf-lmap-framework]
Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
Aitken, P., and A. Akhter, "A framework for large-scale
measurement platforms (LMAP)", draft-ietf-lmap-
framework-03 (work in progress), January 2014.
[RFC1242] Bradner, S., "Benchmarking terminology for network
interconnection devices", RFC 1242, July 1991.
[RFC4148] Stephan, E., "IP Performance Metrics (IPPM) Metrics
Registry", BCP 108, RFC 4148, August 2005.
[RFC5472] Zseby, T., Boschi, E., Brownlee, N., and B. Claise, "IP
Flow Information Export (IPFIX) Applicability", RFC 5472,
March 2009.
[RFC5477] Dietz, T., Claise, B., Aitken, P., Dressler, F., and G.
Carle, "Information Model for Packet Sampling Exports",
RFC 5477, March 2009.
[RFC5481] Morton, A. and B. Claise, "Packet Delay Variation
Applicability Statement", RFC 5481, March 2009.
[RFC6248] Morton, A., "RFC 4148 and the IP Performance Metrics
(IPPM) Registry of Metrics Are Obsolete", RFC 6248, April
2011.
[RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New
Performance Metric Development", BCP 170, RFC 6390,
October 2011.
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[RFC7003] Clark, A., Huang, R., and Q. Wu, "RTP Control Protocol
(RTCP) Extended Report (XR) Block for Burst/Gap Discard
Metric Reporting", RFC 7003, September 2013.
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
URI: http://home.comcast.net/~acmacm/
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
British Telecom
Adastral Park, Martlesham Heath
Ipswich
ENGLAND
Email: philip.eardley@bt.com
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