| Network Working Group | A. Morton |
| Internet-Draft | AT&T Labs |
| Intended status: Standards Track | M. Bagnulo |
| Expires: January 1, 2018 | UC3M |
| P. Eardley | |
| BT | |
| K. D'Souza | |
| AT&T Labs | |
| June 30, 2017 |
Initial Performance Metric Registry Entries
draft-ietf-ippm-initial-registry-04
This memo defines the Initial Entries for the Performance Metrics Registry. This version includes:
* Addition of Loss Ratio metric in various sections (multiple metrics per section).
* All section 4, 5, 6, 7, and 8 parameters reference YANG types for alternate data formats.
* implementation of standard naming format for parameters.
* implementation of many IANA early-review comments.
Still need: Add MBM metric entry.
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.
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 January 1, 2018.
Copyright (c) 2017 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 to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
Note: Efforts to synchronize structure and terminology with [I-D.ietf-ippm-metric-registry] will likely be incomplete until both drafts are stable.
This memo proposes an initial set of entries for the Performance Metric Registry. It uses terms and definitions from the IPPM literature, primarily [RFC2330]. Proponents of Passive Performance Metrics are encouraged to develop a similar document.
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 were intended to become the basis for the columns of an IETF-wide registry of metrics. While examinating aspects of metric 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 Metric 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 Metric 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 Expert Review, which will ensure that the metrics are tightly defined.
This document defines the initial set of Performance Metrics Registry entries, for which IETF approval (following development in the IP Performance Metrics (IPPM) Working Group) will satisfy the requirement for Expert Review. Note that all 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.
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.
Registry Categories and Columns, shown as
Category
------------------
Column | Column |
Summary
------------------------------------------------------------------------
Identifier | Name | URIs | 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 |Request | Rev | Rev.Date |
Comments and Remarks
--------------------
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. 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 two closely-related registry entries. As a result, IANA is also asked to assign corresponding URNs and URLs to each Named Metric.
This category includes multiple indexes to the registry entry: the element ID and metric name.
<insert a numeric identifier, an integer, TBD>
IANA is asked to assign different numeric identifiers to each of the two Named Metrics.
<insert name according to metric naming convention>
RTDelay_Active_IP-UDP-Poisson_RFCXXXXsecY_Seconds_95Percentile
RTLoss_Active_IP-UDP-Poisson_RFCXXXXsecY_Percent_LossRatio
URN: Prefix urn:ietf:metrics:perf:<name>
URL: http://<TBD by IANA>/<name>
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.
IETF
1.0
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.
<Full bibliographic reference to an immutable doc.>
Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip Delay Metric for IPPM", RFC 2681, September 1999.
<specific section reference and additional clarifications, if needed>
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.
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].
<list and specify Fixed Parameters, input factors that must be determined and embedded in the measurement system for use when needed>
Type-P as defined in Section 13 of [RFC2330]:
Other measurement parameters:
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 metric, insert relevant section references and supplemental info>
The methodology for this metric is defined as Type-P-Round-trip-Delay-Poisson-Stream in section 2.6 of RFC 2681 and section 3.6 of RFC 2681 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 (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 MAY 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 dis-ambiguate 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. Section 8 of [RFC6673] presents additional requirements which MUST be included in the method of measurement for this metric.
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/specification references, and description of any new generation parameters, if needed>
Section 11.1.3 of [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 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 Run-time 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.
The measured results based on a filtered version of the packets observed, and this section provides the filter details (when present).
<section reference>.
NA
<insert time distribution details, or how this is diff from the filter>
NA
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, and their data formats>
>>> should Poisson run-time params be fixed instead? probably yes if modeling a specific version of MBA tests.
<lists the names of the different roles from the measurement method>
This category specifies all details of the Output of measurements using the metric.
<insert name of the output type, raw or a selected summary statistic>
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].
<describe the reference data format for each type of result>
For all outputs ---
For
RTDelay_Active_IP-UDP-Poisson_RFCXXXXsecY_Seconds_95Percentile:
For
RTLoss_Active_IP-UDP-Poisson_RFCXXXXsecY_Percent_LossRatio:
<insert units for the measured results, and the reference specification>.
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.
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.
<current or deprecated>
name or RFC, etc.
1.0
YYYY-MM-DD
Additional (Informational) details for this entry
This section gives an initial registry entry for a Packet Delay Variation metric.
Note: If each Registry entry should only produce a "raw" output or a statistical summary, then the "Output" Category can be split and this section can become two closely-related metrics.
This category includes multiple indexes to the registry entries, the element ID and metric name.
<skipping some Summary columns for now>
<insert numeric identifier, an integer>
<insert name according to metric naming convention>
OWPDV_Active_IP-UDP-Poisson_RFCXXXXsecY_Seconds_95Percentile
URI: Prefix urn:ietf:metrics:perf:<name>
URL: http://<TBD by IANA>/<name>
An assessment of packet delay variation with respect to the minimum delay observed on the stream, and the Output is expressed as the 95th percentile of the packet delay variation distribution.
<org or person >
IETF
1.0
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.
<Full bibliographic reference to an immutable doc.>
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]
<specific section reference and additional clarifications, if needed>
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)".
<list and specify Fixed Parameters, input factors that must be determined and embedded in the measurement system for use when needed>
Other measurement parameters:
See the Packet Stream generation category for two additional Fixed Parameters.
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 metric, insert relevant section references and supplemental info>
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 MAY 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 dis-ambiguate 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.
<list of generation parameters and section/spec references if needed>
Section 11.1.3 of [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 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.
<insert the measured results based on a filtered version of the packets observed, and this section provides the filter details (when present), and section reference>.
NA
<insert time distribution details, or how this is diff from the filter>
NA
<list of run-time parameters, and their data formats>
<lists the names of the different roles from the measurement method>
This category specifies all details of the Output of measurements using the metric.
<insert name of the output type, raw or a selected summary statistic>
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.
<the output type and data format for each type of result>
<insert units for the measured results, and the reference specification>.
The 95th Percentile of one-way PDV is expressed in seconds.
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 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).
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 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.
<current or depricated>
<name of individual or RFC, etc.>
1.0
YYYY-MM-DD
<Additional (Informational) details for this entry>
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.
This section gives initial registry entries for DNS Response Latency and Loss. RFC 2681 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 URNs and URLs to each Named Metric.
This category includes multiple indexes to the registry entries, the element ID and metric name.
<skipping some admin columns for now>
<insert numeric identifier, an integer>
IANA is asked to assign different numeric identifiers to each of the two Named Metrics.
<insert name according to metric naming convention>
RTDNS_Active_IP-UDP-Poisson_RFCXXXXsecY_Seconds_Raw
RLDNS_Active_IP-UDP-Poisson_RFCXXXXsecY_Logical_Raw
URI: Prefix urn:ietf:metrics:perf:<name>
URL: http://<TBD by IANA>/<name>
RTDNS: This metric assesses the response time, the interval from the query transmission to the response.
RLDNS: This metric indicates that the respnse was deemed lost. In other words, the response time exceeded the maximum waiting time.
IETF
1.0
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.
<Full bibliographic reference to an immutable doc.>
Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. (and updates)
Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip Delay Metric for IPPM", RFC 2681, September 1999.
<specific section reference and additional clarifications, if needed>
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.
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].
<list and specify Fixed Parameters, input factors that must be determined and embedded in the measurement system for use when needed>
Type-P as defined in Section 13 of [RFC2330]:
Other measurement parameters:
Observation: reply packets will contain a DNS response and may contain RRs.
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 metric, insert relevant section references and supplemental info>
The methodology for this metric is defined as Type-P-Round-trip-Delay-Poisson-Stream in section 2.6 of RFC 2681 and section 3.6 of RFC 2681 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 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 which calculates the RTT value MAY 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. Therefore, sequence numbers or other send-order identification MUST be retained at the Src or included with each packet to dis-ambiguate packet reordering if it occurs. Sequence number is part of the payload described under Fixed Parameters.
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.
IF a DNS response does not arrive within Tmax, the response time is undefined, and RTDNS = 1. The Message ID SHALL be used to disambiguate the successive queries.
@@@@ This would require support of ID generation and population in the Message. An alternative would be to use a random Source port on the Query Message, but we would choose ONE before proceding.
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. 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 information for subsequent reporting as a measured result, along with the Round-Trip Delay.
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 dscribed by providing the list of stream parameters.
<list of generation parameters and section/spec references if needed>
Section 11.1.3 of RFC 2681 provides three methods to generate Poisson sampling intervals. The reciprocal of lambda is the average packet rate, 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.
The measured results based on a filtered version of the packets observed, and this section provides the filter details (when present).
<section reference>.
NA
<insert time distribution details, or how this is diff from the filter>
NA
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, and their data formats>
<lists the names of the different roles from the measurement method>
This category specifies all details of the Output of measurements using the metric.
<insert name of the output type, raw or a selected summary statistic>
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.
<describe the data format for each type of result>
For all outputs:
<insert units for the measured results, and the reference specification>.
RTDNS: Round-trip Delay, dT, is expressed in seconds.
RTLDNS: the Logical value, where 1 = Lost and 0 = Received.
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 portion of the Output result resolution which is the result of system noise, and thus inaccurate.
<current or depricated>
name or RFC, etc.
1.0
YYYY-MM-DD
Additional (Informational) details for this entry
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 a single registry entry, 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 URNs and URLs to each Named Metric.
This category includes multiple indexes to the registry entries, the element ID and metric name.
<insert numeric identifier, an integer, one corresponding to each name below>
IANA is asked to assign different numeric identifiers to each of the six Metrics.
<insert name according to metric naming convention>
OWDelay_Active_IP-UDP-Poisson-Payload250B_RFCXXXXsecY_Seconds_<statistic>
where <statistic> is one of:
OWLoss_Active_IP-UDP-Poisson-Payload250B_RFCXXXXsecY_Percent_LossRatio
URI: Prefix urn:ietf:metrics:perf:<name>
URL: http:\\www.iana.org\ ... <name>
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:
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.
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.
<Full bibliographic reference to an immutable doc.>
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>.
Morton, A., and Stephan, E., "Spatial Composition of Metrics", RFC 6049, January 2011.
<specific section reference and additional clarifications, if needed>
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].
<list and specify Fixed Parameters, input factors that must be determined and embedded in the measurement system for use when needed>
Type-P:
Other measurement parameters:
See the Packet Stream generation category for two additional Fixed Parameters.
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 metric, insert relevant section references and supplemental info>
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 MAY 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 dis-ambiguate packet reordering if it occurs.
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.
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 dscribed by providing the list of stream parameters.
<list of generation parameters and section/spec references if needed>
Section 11.1.3 of RFC 2681 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 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.
NA
NA
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, and their data formats>
<lists the names of the different roles from the measurement method>
This category specifies all details of the Output of measurements using the metric.
<insert name of the output type, raw or a selected summary statistic>
See subsection titles below for Types.
<describe the data format for each type of result>
For all output types ---
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:
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.
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].
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].
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
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.
<insert units for the measured results, and the reference specification>.
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.
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 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).
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 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.
<current or depricated>
name or RFC, etc.
1.0
YYYY-MM-DD
Additional (Informational) details for this entry
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 a single registry entry, 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 URNs and URLs to each Named Metric.
This category includes multiple indexes to the registry entries, the element ID and metric name.
<insert numeric identifier, an integer, one corresponding to each name below>
IANA is asked to assign a different numeric identifiers to each of the six Metrics.
<insert name according to metric naming convention>
OWDelay_Active_IP-UDP-Periodic-Payload142B_RFCXXXXsecY_Seconds_<statistic>
where <statistic> is one of:
OWLoss_Active_IP-UDP-Periodic-Payload142B_RFCXXXXsecY_Percent_LossRatio
URI: Prefix urn:ietf:metrics:perf:<name>
URL: http:\\www.iana.org\ ... <name>
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:
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.
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.
<Full bibliographic reference to an immutable doc.>
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>.
Morton, A., and Stephan, E., "Spatial Composition of Metrics", RFC 6049, January 2011.
<specific section reference and additional clarifications, if needed>
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].
<list and specify Fixed Parameters, input factors that must be determined and embedded in the measurement system for use when needed>
Type-P:
Other measurement parameters:
See the Packet Stream generation category for two additional Fixed Parameters.
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 metric, insert relevant section references and supplemental info>
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 MAY 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 dis-ambiguate packet reordering if it occurs.
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.
<list of generation parameters and section/spec references if needed>
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.
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.
NA
NA
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, and their data formats>
>>> should Periodic run-time params be fixed instead? probably yes if modeling a specific version of tests. Note in the NAME, i.e. Poisson3.3
<lists the names of the different roles from the measurement method>
This category specifies all details of the Output of measurements using the metric.
<insert name of the output type, raw or a selected summary statistic>
See subsection titles in Data Format for Types.
<describe the data format for each type of result>
For all output types ---
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:
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.
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].
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].
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
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.
<insert units for the measured results, and the reference specification>.
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.
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 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).
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 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.
<current or depricated>
name or RFC, etc.
1.0
YYYY-MM-DD
Additional (Informational) details for this entry
This section gives an initial registry entry for ....
This category includes multiple indexes to the registry entries, the element ID and metric name.
<insert numeric identifier, an integer>
<insert name according to metric naming convention>
URI: Prefix urn:ietf:metrics:perf:<name>
URL:
TBD.
<reference to the RFC of spec where the registry entry is defined>
<org or person >
<currently 1.0>
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.
<Full bibliographic reference to an immutable doc.>
<specific section reference and additional clarifications, if needed>
<list and specify Fixed Parameters, input factors that must be determined and embedded in the measurement system for use when needed>
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 metric, insert relevant section references and supplemental info>
<list of generation parameters and section/spec references if needed>
<insert the measured results based on a filtered version of the packets observed, and this section provides the filter details (when present), and section reference>.
<insert time distribution details, or how this is diff from the filter>
<list of run-time parameters, and any reference(s)>.
<lists the names of the different roles from the measurement method>
This category specifies all details of the Output of measurements using the metric.
<insert name of the output type, raw or a selected summary statistic>
<pointer to section/spec where output type/format is defined>
<insert units for the measured results, and the reference specification>.
<describe the error calibration, a way to indicate that the results were collected in a calbration mode of operation, and a way to report internal status metrics related to calibration, such as time offset>
<current or depricated>
<name of individual or Internet Draft, etc.>
1.0
YYYY-MM-DD
Additional (Informational) details for this entry
This section is MAY BE DELETED or adapted before submission.
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.
This category includes multiple indexes to the registry entries, the element ID and metric name.
An integer having enough digits to uniquely identify each entry in the Registry.
A metric naming convention is TBD.
Prefix urn:ietf:metrics:param:<name>
current
Alcelip Mornuley
1.0
2014-07-04
TBD.
[RFC3611][RFC4566][RFC6776][RFC6792][RFC7003]
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.
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.
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
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.
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].
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.
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.
The output type defines the type of result that the metric produces.
The measured results are apparently expressed in packets, although there is no section of [RFC7003] titled "Metric Units".
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)
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
TBD.
This section may be removed for publication. It contains partial information on updtes.
This draft replaced draft-mornuley-ippm-initial-registry.
In version 02, Section 4 has been edited to reflect recent discussion on the ippm-list: * Removed the combination or "Raw" and left 95th percentile. * Hanging Indent on Run-time parameters (Fixed parameters use bullet lists and other indenting formats. * Payload format for measurement has been removed. * Explanation of Conditional delay distribution.
Version 03 addressed Phil Eardley's comments and suggestions in sections 1-4. and resolved the definition of Percentiles.
Version 04 * All section 4 parameters reference YANG types for alternate data formats. * Discussion has concluded that usecase(s) for machine parse-able registry columns are not needed.
These registry entries represent no known security implications for Internet Security. Each referenced Metric contains a Security Considerations section.
IANA is requested to populate The Performance Metric Registry defined in [I-D.ietf-ippm-metric-registry] with the values defined above.
See the IANA Considerations section of [I-D.ietf-ippm-metric-registry] for additional requests and considerations.
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, 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, and participants in the LMAP working group. Thanks to Michelle Cotton for her early IANA review, and to Amanda Barber for answering questions related to the presentation of the registry and accessibility of the complete template via URL.