| IPPM Working Group | A. Akhter |
| Internet-Draft | B. Claise |
| Intended status: Best Current Practice | Cisco Systems, Inc. |
| Expires: January 5, 2015 | July 4, 2014 |
Passive Performance Metrics Sub-Registry
draft-ietf-ippm-registry-passive-01.txt
This document specifies the Passive Performance Metrics sub-registry of the Performance Metric Registry. This sub-registry contains Passive 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.
This document specifies a way to organize registry entries into columns that are well-defined, permitting consistent development of entries over time (a column may be 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-ietf-ippm-metric-registry).
The document contains example entries for the Passive Performance Metrics sub-registry: a registry entry for a passive metric based on octetTotalCount as defined in RFC5102 and a protocol specific passive metric based on RTP packets lost as defined in RFC3550. The examples are for Informational purposes and do not create any entry in the IANA registry.
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].
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 5, 2015.
Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved.
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The IETF has been specifying and continues to specify Performance Metrics. While IP Performance Metrics (IPPM) is the working group (WG) primarily focusing on Performance Metrics definition at the IETF, other working groups, have also specified Performance Metrics:
It is expected that more and more Performance Metrics will be defined in the future, not only IP based metrics, but also protocol-specific ones and application-specific ones.
"Registry for Performance Metrics" [I-D.ietf-ippm-metric-registry] specifies a common registry for Performance Metrics. This document specifies the creation of a sub-registry specific to Performance Metrics metered by an Passive Measurement Method (passive metrics). Note that a sister document, "Active Performance Metric Sub-Registry" [I-D.ietf-ippm-registry-active], specifies a sub-registry for the active metric (Performance Metrics metered by an Active Measurement.
The Passive Performance Measurements Sub-Registry contains passive performance metrics that meet the criteria set by the IETF and review of the Performance Metric Experts. It is expected that the majority of the metrics will have been defined elsewhere within the IETF working groups such as IPPM, BMWG, IPFIX, etc.
This sub-registry is part of the Performance Metric Registry [I-D.ietf-ippm-metric-registry] which specifies that all sub-registries must contain at least the following common fields: the identifier, the name, the URI, the status, the requester, the revision, the revision date, the description, and the reference specification(s). In addition to these common fields the passive metrics sub-registry has additional fields that provide the necessary background for interoperability and adoption.
"Registry for Performance Metrics" [I-D.ietf-ippm-metric-registry] specifies the following terms: Performance Metric, Registered Performance Metric, Performance Metrics Registry (also known as Registry), Proprietary Registry, Performance Metrics Experts, Performance Metrics Directorate, Parameter, Active Measurement Method, Passive Measurement Method, and Hybrid Measurement Method.
Capitalized terms used in this document that are defined in the Terminology section of [I-D.ietf-ippm-metric-registry] are to be interpreted as defined there.
EDITOR's NOTE: from draft-manyfolks-ippm-metric-registry-00. Proposal: we can simply refers to draft-ietf-ippm-registry-active-00 section 5, instead of duplicating text.
IPPM Passive Performance Metric registration is meant to allow wider adoption of common metrics in an inter-operable way. There are challenges with metric interoperability and adoption (to name a few) due to flexible input parameters, confusion between many similar metrics, and varying output formats.
One clear motivation for having such a registry is to allow a controller to request a measurement agent to perform 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 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.
[I-D.ietf-ippm-metric-registry] defines the overall structure for a Performance Metric Registry and provides guidance for defining a sub registry.
This document defines the Passive Performance Metrics Sub-registry; passive metrics are those where the measurements are based the observation of on network traffic, generated either from the end users or from network elements. Specifically, this traffic has not been generated for the purpose of measurement.
A row in the registry corresponds to one Registered Performance Metric, with entries in the various columns specifying the metric. Section 6 defines the additional columns for a Registered Passive Performance Metric.
As discussed in [I-D.ietf-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.
This section defines the categories and columns of the registry. Below, categories are described at the 6.x heading level, and columns are at the 6.x.y heading level. There are three categories, divided into common information (from [I-D.ietf-ippm-metric-registry]), metric definition and an open Comments section.
This category has multiple indexes to each registry entry. It is defined in [I-D.ietf-ippm-metric-registry]:
Defined in [I-D.ietf-ippm-metric-registry]. Definition text to be copied once source is stable.
Defined in [I-D.ietf-ippm-metric-registry], same comment as above.
Defined in [I-D.ietf-ippm-metric-registry], same comment as above.
Defined in [I-D.ietf-ippm-metric-registry], same comment as above.
Defined in [I-D.ietf-ippm-metric-registry], same comment as above.
Defined in [I-D.ietf-ippm-metric-registry], same comment as above.
Defined in [I-D.ietf-ippm-metric-registry], same comment as above.
Defined in [I-D.ietf-ippm-metric-registry], same comment as the above.
Defined in [I-D.ietf-ippm-metric-registry], same comment as the above.
This category includes columns to prompt all necessary details related to the passive performance metric definition, including the RFC reference and values of input factors, called fixed parameters, which are left open in the origin definition but have a particular value defined by the performance metric.
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.
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, for RTP packet loss calculation relies on the validation of a packet as RTP which is a multi-packet validation controlled by MIN_SEQUENTIAL as defined by [RFC3550]. Varying MIN_SEQUENTIAL values can alter the loss report and this value could be set as a fixed parameter.
A Parameter which is Fixed for one Registry entry may be designated as a Run-time Parameter for another Registry entry.
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.
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.
Specifically, this section should include pointers to pseudocode or actual code that could be used for an unambigious implementation.
The filter specifies the traffic constraints that the passive measurement method used is valid (or invalid) for. This includes valid packet sampling ranges, width of valid traffic matches (eg. all traffic on interface, UDP packets packets in a flow (eg. same RTP session).
It is possible that the measurement method may not have a specific limitation. However, this specific registry entry with it's combination of fixed parameters implies restrictions. These restrictions would be listed in this field.
Measurement timing defines the behavior of the measurement method with respect to timing.
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:
The output type defines the type of result that the metric produces. It can be the raw result(s) 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").
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.
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).
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.
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.
tbd
This section is Informational.
This section gives an example registry entry for a generalized the passive metric octetDeltaCount described in [RFC5102].
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.
TBD by IANA.
A metric naming convention is TBD.
One possibility based on the proposal in [I-D.ietf-ippm-metric-registry]:
Pas_IP-Octet-Delta-General
urn:ietf:params:performance:metric-something
Current
TBD
0
TBD
A delta count of the number of octets observed.
octetDeltaCount described in section 5.10.1 of [RFC5102]
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.
octetDeltaCount described in section 5.10.1 of [RFC5102]
As this is the generalised version of the IP delta count metric, there are no fixed parameters.
For <metric>.
<section reference>
This measurement only covers IP packets and the IP payload (including the IP header) of these packets. Non-IP packets (BPDUs, ISIS) will not be accounted. Layer 2 overhead (Ethernet headers, MPLS, QinQ, etc.) will also not be represented in the measurement.
This is a continous measurement of the IP octets seen in the traffic selection scope (run-time parameter).
The measurement interval is a run time parameter.
There is no sampling.
It is possible that multiple observation intervals are reported in a single report. In such a case concatination of the interval reports (deltaOctetCount, start-time, end-time) is allowed.
The delta octet count metric reports a observation start time and end time.
The measured results are expressed in octets with a data format of unsigned64 as described in [RFC5102]
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.
Additional (Informational) details for this entry
tbd
This section is Informational.
This section gives an example registry entry for accounting of outgoing WAN IP traffic the passive metric in terms of octetDeltaCount, as described in [RFC5102].
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.
TBD by IANA.
A metric naming convention is TBD.
One possibility based on the proposal in [I-D.ietf-ippm-metric-registry]:
Pas_IP-Octet-Delta-WAN-egress
urn:ietf:params:performance:metric-something
Current
TBD
0
TBD
A delta count of the number of octets observed outgoing on WAN interface.
octetDeltaCount described in section 5.10.1 of [RFC5102]
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.
octetDeltaCount described in section 5.10.1 of [RFC5102]
As this is a specific version of Pas_IP-Octet-Delta-General that performs metering of all outgoing WAN traffic.
For <metric>.
<section reference>
This measurement only covers IP packets observed in the WAN outgoing direction. The bytes counted are the IP payload (including the IP header) of these packets. Non-IP packets (BPDUs, ISIS) will not be accounted. Layer 2 overhead (Ethernet headers, MPLS, QinQ, etc.) will also not be represented in the measurement.
This is a continous measurement of the IP octets seen in the traffic selection scope (run-time parameter), each of a 5 minute duration.
There is no sampling.
It is possible that multiple observation intervals are reported in a single report. In such a case concatination of the interval reports (deltaOctetCount, start-time, end-time) is allowed.
The delta octet count metric reports a observation start time and end time.
The measured results are expressed in octets with a data format of unsigned64 as described in [RFC5102]
There are no run-time parameters for this registry entry.
Additional (Informational) details for this entry
tbd
This section is Informational. (?)
This section gives an example registry entry for the <type of metric and specification reference> .
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.
urn:ietf:params:performance:metric-something
Current
TBD
0
TBD
A metric Description is TBD.
Section YY, RFCXXXX
< possible section reference>
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>
For <metric>.
<section reference>
<list filter criteria limitations and allowances >
< list timing requirements and limitations >
The output types define the type of result that the metric produces.
The measured results are expressed in <units>,
<section reference>.
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)>.
Additional (Informational) details for this entry
This registry has no known implications on Internet Security.
IANA is requested to create The Passive Performance Metric Sub-registry within the Performance Metric Registry defined in [I-D.ietf-ippm-metric-registry]. The Sub-registry will contain the following categories and (bullet) columns, (as defined in section 6 above):
Common Registry Indexes and Info
Metric Definition
Method of Measurement
Comments and Remarks
The authors thank the prior work of Al Morton, Marcelo Bagnulo and Phil Eardley in "draft-ietf-ippm-registry-active" which was used both as a template for this document and source of text.
| [I-D.ietf-ippm-metric-registry] | Bagnulo, M., Claise, B., Eardley, P. and A. Morton, "Registry for Performance Metrics", Internet-Draft draft-ietf-ippm-metric-registry-00, July 2014. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. |