Internet Engineering Task Force (IETF) A. Morton
Request for Comments: 6248 AT&T Labs
Obsoletes: 4148 April 2011
Updates: 4737, 5560, 5644, 6049
RFC 4148 and the IP Performance Metrics (IPPM) Registry of Metrics
This memo reclassifies RFC 4148, "IP Performance Metrics (IPPM)
Metrics Registry", as Obsolete, and withdraws the IANA IPPM Metrics
Registry itself from use because it is obsolete. The current
registry structure has been found to be insufficiently detailed to
uniquely identify IPPM metrics. Despite apparent efforts to find
current or even future users, no one responded to the call for
interest in the RFC 4148 registry during the second half of 2010.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
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Table of Contents
1. Introduction ....................................................22. Action to Reclassify RFC 4148 and the Corresponding IANA
Registry as Obsolete ............................................33. Security Considerations .........................................44. IANA Considerations .............................................45. Acknowledgements ................................................46. References ......................................................56.1. Normative References .......................................56.2. Informative References .....................................51. Introduction
The IP Performance Metrics (IPPM) framework [RFC2330] describes
several ways to record options and metric parameter settings, in
order to account for sources of measurement variability. For
example, Section 13 of [RFC2330] describes the notion of "Type P" so
that metrics can be specified in general, but the specifics (such as
payload length in octets and protocol type) can replace P to
disambiguate the results.
When the IPPM Metrics Registry [RFC4148] was designed, the
variability of the "Type P" notion, and the variability possible with
the many metric parameters (see Section 4.2 of [RFC2679]), were not
fully appreciated. Further, some of the early metric definitions
only indicate Poisson streams [RFC2330] (see the metrics in
[RFC2679], [RFC2680], and [RFC3393]), but later work standardized the
methods for Periodic Stream measurements [RFC3432], adding to the
variability possible when characterizing a metric exactly.
It is not believed to be feasible or even useful to register every
possible combination of Type P, metric parameters, and Stream
parameters using the current structure of the IPPM Metrics Registry.
The IPPM Metrics Registry is believed to have very few users, if any.
Evidence of this was provided by the fact that one registry entry was
syntactically incorrect for months after [RFC5644] was published.
The text ":=" was used for the metrics in that document instead of
"::=". It took eight months before someone offered that a parser
found the error. Even the original registry author agrees that the
current registry is not efficient, and has submitted a proposal to
effectively create a new registry.
Despite apparent efforts to find current or even future users, no one
responded to the call for interest in the RFC 4148 registry during
the second half of 2010. Therefore, the IETF now declares the
registry Obsolete without any further reservations.
When a registry is designated Obsolete, it simply prevents the IANA
from registering new objects, in this case new metrics. So, even if
a registry user was eventually found, they could continue to use the
current registry, and its contents will continue to be available.
The most recently published memo that added metrics to the registry
is [RFC6049]. This memo updates all previous memos that registered
new metrics, including [RFC4737] and [RFC5560], so that the
registry's Obsolete status will be evident.
2. Action to Reclassify RFC 4148 and the Corresponding IANA Registry as
Due to the ambiguities between the current metrics registrations and
the metrics used, and the apparent minimal adoption of the registry
in practice, it is required that:
o the IETF reclassify [RFC4148] as Obsolete.
o the IANA withdraw the current IPPM Metrics Registry from further
updates and note that it too is Obsolete.
It is assumed that parties who wish to establish a replacement
registry function will work to specify such a registry.
3. Security Considerations
This memo and its recommendations have no known impact on the
security of the Internet (especially if there is a zombie apocalypse
on the day it is published; humans will have many more security
issues to worry about stemming from the rise of the un-dead).
4. IANA Considerations
Metrics defined in the IETF have been typically registered in the
IANA IPPM Metrics Registry as described in the initial version of the
registry [RFC4148]. However, areas for improvement of this registry
have been identified, and the registry structure has to be revisited
when there is working group consensus to do so.
The current consensus is to designate the IPPM Metrics Registry,
originally described in [RFC4148], as Obsolete.
The DESCRIPTION of the registry MIB has been modified as follows, and
the first two sentences should be included on any IANA-maintained web
page describing this registry or its contents:
"With the approval and publication of RFC 6248, this module is
The registry will no longer be updated, and the current contents
will be maintained as-is on the day that RFC 6248 was published.
The original Description text follows below:
This module defines a registry for IP Performance Metrics.
Henk Uijterwaal suggested additional rationale for the recommendation
in this memo.
6.1. Normative References
[RFC4148] Stephan, E., "IP Performance Metrics (IPPM) Metrics
Registry", BCP 108, RFC 4148, August 2005.
6.2. Informative References
[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", RFC 2330,
[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.
[RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation
Metric for IP Performance Metrics (IPPM)", RFC 3393,
[RFC3432] Raisanen, V., Grotefeld, G., and A. Morton, "Network
performance measurement with periodic streams", RFC 3432,
[RFC4737] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,
S., and J. Perser, "Packet Reordering Metrics", RFC 4737,
[RFC5560] Uijterwaal, H., "A One-Way Packet Duplication Metric",
RFC 5560, May 2009.
[RFC5644] Stephan, E., Liang, L., and A. Morton, "IP Performance
Metrics (IPPM): Spatial and Multicast", RFC 5644,
[RFC6049] Morton, A. and E. Stephan, "Spatial Composition of
Metrics", RFC 6049, January 2011.