draft-ietf-ippm-multimetrics-00.txt   draft-ietf-ippm-multimetrics-01.txt 
Network Working Group E. Stephan Network Working Group E. Stephan
Internet-Draft France Telecom Internet-Draft France Telecom
Expires: July 14, 2006 L. Liang Expires: December 27, 2006 L. Liang
University of Surrey University of Surrey
A. Morton A. Morton
AT&T Labs AT&T Labs
January 10, 2006 June 25, 2006
IP Performance Metrics (IPPM) for spatial and multicast IP Performance Metrics (IPPM) for spatial and multicast
draft-ietf-ippm-multimetrics-00.txt draft-ietf-ippm-multimetrics-01
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The Internet Society (2006).
Abstract Abstract
The IETF IP Performance Metrics (IPPM) working group has standardized The IETF IP Performance Metrics (IPPM) working group has standardized
metrics for measuring end-to-end performance between 2 points. This metrics for measuring end-to-end performance between 2 points. This
memo defines 2 sets of metrics to extend these end-to-end ones. It memo defines 2 sets of metrics to extend these end-to-end ones. It
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2.1. Multiparty metric . . . . . . . . . . . . . . . . . . . . 5 2.1. Multiparty metric . . . . . . . . . . . . . . . . . . . . 5
2.2. Spatial metric . . . . . . . . . . . . . . . . . . . . . . 5 2.2. Spatial metric . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Spatial metric points of interest . . . . . . . . . . . . 5 2.3. Spatial metric points of interest . . . . . . . . . . . . 5
2.4. One-to-group metric . . . . . . . . . . . . . . . . . . . 5 2.4. One-to-group metric . . . . . . . . . . . . . . . . . . . 5
2.5. One-to-group metric points of interest . . . . . . . . . . 5 2.5. One-to-group metric points of interest . . . . . . . . . . 5
2.6. Reference point . . . . . . . . . . . . . . . . . . . . . 5 2.6. Reference point . . . . . . . . . . . . . . . . . . . . . 5
2.7. Group of singletons . . . . . . . . . . . . . . . . . . . 6 2.7. Group of singletons . . . . . . . . . . . . . . . . . . . 6
3. Motivations for spatial and one-to-group metrics . . . . . . . 6 3. Motivations for spatial and one-to-group metrics . . . . . . . 6
3.1. spatial metrics . . . . . . . . . . . . . . . . . . . . . 6 3.1. spatial metrics . . . . . . . . . . . . . . . . . . . . . 6
3.2. One-to-group metrics . . . . . . . . . . . . . . . . . . . 7 3.2. One-to-group metrics . . . . . . . . . . . . . . . . . . . 7
3.3. Discussion on Group-to-one and Group-to-group metrics . . 7 3.3. Discussion on Group-to-one and Group-to-group metrics . . 8
4. Spatial metrics definitions . . . . . . . . . . . . . . . . . 8 4. Spatial metrics definitions . . . . . . . . . . . . . . . . . 8
4.1. A Definition for Spatial One-way Delay Stream . . . . . . 8 4.1. A Definition for Spatial One-way Delay Stream . . . . . . 8
4.2. A Definition of a sample of One-way Delay of a sub path . 11 4.2. A Definition of a sample of One-way Delay of a sub path . 11
4.3. A Definition for Spatial One-way Packet Loss Stream . . . 13 4.3. A Definition for Spatial One-way Packet Loss Stream . . . 13
4.4. A Definition for Spatial One-way Jitter Stream . . . . . . 15 4.4. A Definition for Spatial One-way Jitter Stream . . . . . . 15
4.5. Discussion on pure passive measurement of spatial 4.5. Pure Passive Metrics . . . . . . . . . . . . . . . . . . . 17
metrics . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.6. Discussion on spatial statistics . . . . . . . . . . . . . 19
4.6. Discussion on spatial statistics . . . . . . . . . . . . . 18 5. One-to-group metrics definitions . . . . . . . . . . . . . . . 19
5. One-to-group metrics definitions . . . . . . . . . . . . . . . 18 5.1. A Definition for one-to-group One-way Delay Stream . . . . 19
5.1. A Definition for one-to-group One-way Delay Stream . . . . 18
5.2. A Definition for one-to-group One-way Packet Loss 5.2. A Definition for one-to-group One-way Packet Loss
Stream . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Stream . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.3. A Definition for one-to-group One-way Jitter Stream . . . 20 5.3. A Definition for one-to-group One-way Jitter Stream . . . 21
5.4. Discussion on one-to-group statistics . . . . . . . . . . 21 5.4. Discussion on one-to-group statistics . . . . . . . . . . 22
6. Extension from one-to-one to one-to-many measurement . . . . . 23 6. Extension from one-to-one to one-to-many measurement . . . . . 24
7. Open issues . . . . . . . . . . . . . . . . . . . . . . . . . 24 7. Open issues . . . . . . . . . . . . . . . . . . . . . . . . . 25
8. Security Considerations . . . . . . . . . . . . . . . . . . . 24 8. Security Considerations . . . . . . . . . . . . . . . . . . . 25
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26
11.1. Normative References . . . . . . . . . . . . . . . . . . . 25 11.1. Normative References . . . . . . . . . . . . . . . . . . . 26
11.2. Informative References . . . . . . . . . . . . . . . . . . 25 11.2. Informative References . . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 27 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 28
Intellectual Property and Copyright Statements . . . . . . . . . . 28 Intellectual Property and Copyright Statements . . . . . . . . . . 29
1. Introduction 1. Introduction
The metrics specified in this memo are built on notions introduced The metrics specified in this memo are built on notions introduced
and discussed in the IPPM Framework document, RFC 2330 [RFC2330]. and discussed in the IPPM Framework document, RFC 2330 [RFC2330].
The reader should be familiar with these documents. The reader should be familiar with these documents.
This memo makes use of definitions of end-to-end One-way Delay This memo makes use of definitions of end-to-end One-way Delay
Metrics defined in the RFC 2679 [RFC2679] to define metrics for Metrics defined in the RFC 2679 [RFC2679] to define metrics for
decomposition of end-to-end one-way delays measurements. decomposition of end-to-end one-way delays measurements.
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be introduced to decompose an end-to-end Type-P-One-way-Packet- be introduced to decompose an end-to-end Type-P-One-way-Packet-
Loss in a spatial sequence of packet loss. Loss in a spatial sequence of packet loss.
o Using the Type-P-Spatial-One-way-Delay-Stream metric, a 'sample', o Using the Type-P-Spatial-One-way-Delay-Stream metric, a 'sample',
called Type-P-Spatial-One-way-Jitter-Stream, will be introduced to called Type-P-Spatial-One-way-Jitter-Stream, will be introduced to
decompose an end-to-end Type-P-One-way-ipdv in a spatial sequence decompose an end-to-end Type-P-One-way-ipdv in a spatial sequence
of jitter. of jitter.
o Using the Type-P-Spatial-One-way-Delay-Stream metric, a 'sample', o Using the Type-P-Spatial-One-way-Delay-Stream metric, a 'sample',
called Type-P-subpath-One-way-Delay-Stream, will be introduced to called Type-P-subpath-One-way-Delay-Stream, will be introduced to
define the one-way-delay between any host of the path. This define the one-way-delay between any host of the path.
metrics is designed too for pure passive measurement methodology
o Using Type-P-subpath-x-Stream, a 'sample' Type-P-Passive-x-Stream
will be introduced to define the Passive metrics. These metrics
are designed for pure passive measurement methodology as
introduced by PSAMP WG. introduced by PSAMP WG.
Then it defines one-to-group metrics. Then it defines one-to-group metrics.
o Using one test packet sent from one sender to a group of o Using one test packet sent from one sender to a group of
receivers, a 'sample', called Type-P-one-to-group-One-way-Delay- receivers, a 'sample', called Type-P-one-to-group-One-way-Delay-
Stream, will be introduced to define the list of Type-P-one-way- Stream, will be introduced to define the list of Type-P-one-way-
delay between this sender and the group of receivers. delay between this sender and the group of receivers.
o Using one test packet sent from one sender to a group of o Using one test packet sent from one sender to a group of
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the location of the lost of packets and the decomposition of the the location of the lost of packets and the decomposition of the
jitter over the path. jitter over the path.
o Monitoring the QoS of a multicast tree, of MPLS point-to- o Monitoring the QoS of a multicast tree, of MPLS point-to-
multipoint and inter-domain communication require spatial multipoint and inter-domain communication require spatial
decomposition of the one-way delay, of the packet loss and of the decomposition of the one-way delay, of the packet loss and of the
jitter. jitter.
o Composition of metrics is a need to scale in the measurement o Composition of metrics is a need to scale in the measurement
plane. The definition of composition metrics is a work in plane. The definition of composition metrics is a work in
progress [I-D.morton-ippm-composition]; . Spatial measure give progress [I-D.ietf-ippm-spatial-composition]; . Spatial measure
typically the individual performance of an intra domain segment. give typically the individual performance of an intra domain
It is the elementary piece of information to exchange for segment. It is the elementary piece of information to exchange
measuring interdomain performance based on composition of metrics. for measuring interdomain performance based on composition of
metrics.
o The PSAMP WG defines capabilities to sample packets in a way to to o The PSAMP WG defines capabilities to sample packets in a way to to
support measurement. [I-D.boschi-export-perpktinfo]; defines a support measurement. [I-D.boschi-ipfix-reducing-redundancy];
method to collect packets information to measure the instantaneous defines a method to collect packets information to measure the
spatial performance without injecting test traffic. Consequently instantaneous spatial performance without injecting test traffic.
it is urgent to define a set of common spatial metrics for passive Consequently it is urgent to define a set of common spatial
and active techniques which respect the IPPM framework [RFC2330]. metrics for passive and active techniques which respect the IPPM
This need is emphases by the fact that end-to-end spatial framework [RFC2330]. This need is emphases by the fact that end-
measurement involves the 2 techniques; to-end spatial measurement involves the 2 techniques;
3.2. One-to-group metrics 3.2. One-to-group metrics
While the node-to-node based spatial measures can provide very useful While the node-to-node based spatial measures can provide very useful
data in the view of each connection, we also need measures to present data in the view of each connection, we also need measures to present
the performance of a multiparty communication in the view of a group the performance of a multiparty communication in the view of a group
with consideration that it involves a group of people rather than with consideration that it involves a group of people rather than
two. As a consequence a simple one-way metric cannot describe the two. As a consequence a simple one-way metric cannot describe the
multi-connection situation. We need some new metrics to collect multi-connection situation. We need some new metrics to collect
performance of all the connections for further statistics analysis. performance of all the connections for further statistics analysis.
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value of Bi of 0 means that dTi is a finite value, and a value of 1 value of Bi of 0 means that dTi is a finite value, and a value of 1
means that dTi is undefined. means that dTi is undefined.
4.3.5. Discussion 4.3.5. Discussion
Following are specific issues wich may occur: Following are specific issues wich may occur:
o the result includes the sequence 1,0. This case means that the o the result includes the sequence 1,0. This case means that the
packet was seen by a host but not by it successor on the path; packet was seen by a host but not by it successor on the path;
4.3.6. Discussion o
The location of the meter in the device influences the result: The location of the meter in the device influences the result:
o Even if the packet is received by a device, it may be not observed o Even if the packet is received by a device, it may be not observed
by a meter located after a buffer; by a meter located after a buffer;
4.3.7. Sections in progress 4.3.6. Reporting
Section in progress.
4.4. A Definition for Spatial One-way Jitter Stream 4.4. A Definition for Spatial One-way Jitter Stream
This section uses parameters from the definition of Type-P-One-way- This section uses parameters from the definition of Type-P-One-way-
ipdv. When a parameter from section 2 of [RFC3393] is first used in ipdv. When a parameter from section 2 of [RFC3393] is first used in
this section, it will be tagged with a trailing asterisk. this section, it will be tagged with a trailing asterisk.
Sections 3.5 to 3.7 of [RFC3393] give requirements and applicability Sections 3.5 to 3.7 of [RFC3393] give requirements and applicability
statements for end-to-end one-way-ipdv measurements. They are statements for end-to-end one-way-ipdv measurements. They are
applicable to each point of interest Hi involved in the measure. applicable to each point of interest Hi involved in the measure.
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dT2.i-dT1.i is either a real number if the packets P1 and P2 passes dT2.i-dT1.i is either a real number if the packets P1 and P2 passes
Hi at wire-time (last bit) dT1.i, respectively dT2.i, or undefined if Hi at wire-time (last bit) dT1.i, respectively dT2.i, or undefined if
at least one of them never passes Hi. T2-T1 is the inter-packet at least one of them never passes Hi. T2-T1 is the inter-packet
emission interval and dT2-dT1 is ddT* the Type-P-One-way-ipdv at emission interval and dT2-dT1 is ddT* the Type-P-One-way-ipdv at
T1,T2*. T1,T2*.
4.4.5. Sections in progress 4.4.5. Sections in progress
See sections 3.5 to 3.7 of [RFC3393]. See sections 3.5 to 3.7 of [RFC3393].
4.5. Discussion on pure passive measurement of spatial metrics 4.5. Pure Passive Metrics
Spatial metrics may be measured without injecting test traffic as Spatial metrics may be measured without injecting test traffic as
described in [I-D.boschi-export-perpktinfo] even if such a technique described in [I-D.boschi-ipfix-reducing-redundancy] .
have some limitations.
o The packet is not a test packet, so it does not include the time 4.5.1. Discussion on Passive measurement
it was sent. Consequently a point of interest Hi ignores the time
the packet was send. So It is not possible to measure the first
hop delay. The collector ignores the time the packet was
received. So it is not possible to measure the last hop delay.
One might says that most of the operational issues occur in the
last mile and that consequently such measure are not useful.
Nevertheless they are usable for network TE and interdomain QoS
monitoring.
o The collector ignores the time the packet was send. So it is not One might says that most of the operational issues occur in the last
possible to determine that it is lost. mile and that consequently such measure are less useful than active
measuremeent. Nevertheless they are usable for network TE and
interdomain QoS monitoring, and composition of metric.
o A point of interest Hi ignores the time the packet is send because Such a technique have some limitations that are discussed below.
4.5.1.1. Passive One way delay
As the packet is not a test packet, it does not include the time it
was sent.
Consequently a point of interest Hi ignores the time the packet was
send. So It is not possible to measure the delay between Src and Hi
in the same manner it is not possible to measure the delay betwwen Hi
and Dst.
4.5.1.2. Passive Packet loss
The packet is not a test packet, so it does not include a sequence
number.
Packet lost measurement doe not require time synchronization and
require only one point of observation. Nevertheless it requires the
point of interest Hi to be expecting the packet. Practically Hi may
not detect a lost of packet that occurs between Src and Hi.
A point of interest Hi ignores the time the packet is send because
the packet does not carry the time it was injected in the network. the packet does not carry the time it was injected in the network.
So a probe Hi can not compute dTi. So a probe Hi can not compute dTi.
An alternative to these issues consist in considering that T is the An alternative to these issues consist in considering sample spatial
time when H1 (the first passive probe of the path) observed the One-way delay that T is the time when H1 (the first passive probe of
packet. the path) observed the packet.
4.5.2. Reporting and composition
To avoid misunderstanding and to address specific reporting To avoid misunderstanding and to address specific reporting
constraint a proposal consists in defining distinct metrics for pure constraint a proposal consists in defining distinct metrics for pure
passive measurement based on the definition above. Having distinct passive measurement based on the definition above.
metrics identifiers for spatial metrics and passive spatial metrics
in the [RFC4148] will avoid interoperabily issues. They may be named It is crucial to know the methodologie used because of the difference
of method of detection (expecting Seq++); because of the difference
of source of time (H1 vs Src) and because of the difference of
behavior of the source (Poisson/unknown).
4.5.3. naming and registry
Having distinct metrics identifiers for spatial metrics and passive
spatial metrics in the [RFC4148] will avoid interoperabily issues
especially during composition of metrics.
They may be named
o Type-P-Passive-One-way-delay-Stream o Type-P-Passive-One-way-delay-Stream
o Type-P-Passive-One-way-Packet-Loss-Stream o Type-P-Passive-One-way-Packet-Loss-Stream
o Type-P-Passive-One-way-jitter-Stream o Type-P-Passive-One-way-jitter-Stream
In the same way sample should be registred too. they may be named
o Type-P-Passive-One-way-delay-Sample
o Type-P-Passive-One-way-Packet-Loss-Sample
o Type-P-Passive-One-way-jitter-Sample
4.5.4. Passive One way delay metrics
4.5.5. Passive One way PacketLoss metrics
4.5.6. Passive One way jitter metrics
4.6. Discussion on spatial statistics 4.6. Discussion on spatial statistics
Do we define min, max, avg of spatial metrics ? Do we define min, max, avg of spatial metrics ?
having the maximum loss metric value could be interesting. Say, having the maximum loss metric value could be interesting. Say,
the segment between router A and B always contributes loss metric the segment between router A and B always contributes loss metric
value of "1" means it could be the potential problem segment. value of "1" means it could be the potential problem segment.
Uploading dTi of each Hi consume a lot of bandwidth. Computing Uploading dTi of each Hi consume a lot of bandwidth. Computing
statistics (min, max and avg) of dTi locally in each Hi reduce the statistics (min, max and avg) of dTi locally in each Hi reduce the
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[RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation [RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation
Metric for IP Performance Metrics (IPPM)", RFC 3393, Metric for IP Performance Metrics (IPPM)", RFC 3393,
November 2002. November 2002.
[RFC4148] Stephan, E., "IP Performance Metrics (IPPM) Metrics [RFC4148] Stephan, E., "IP Performance Metrics (IPPM) Metrics
Registry", BCP 108, RFC 4148, August 2005. Registry", BCP 108, RFC 4148, August 2005.
11.2. Informative References 11.2. Informative References
[I-D.boschi-export-perpktinfo] [I-D.boschi-ipfix-reducing-redundancy]
Boschi, E. and L. Mark, "Use of IPFIX for Export of Per- Boschi, E. and L. Mark, "Reducing redundancy in IPFIX and
Packet Information", draft-boschi-export-perpktinfo-01 PSAMP reports", draft-boschi-ipfix-reducing-redundancy-01
(work in progress), October 2005. (work in progress), March 2006.
[I-D.morton-ippm-composition] [I-D.ietf-ippm-spatial-composition]
Stephan, E. and A. Morton, "Spatial Composition of Morton, A. and E. Stephan, "Spatial Composition of
Metrics", draft-morton-ippm-composition-01 (work in Metrics", draft-ietf-ippm-spatial-composition-00 (work in
progress), October 2005. progress), February 2006.
[I-D.quittek-ipfix-middlebox] [I-D.quittek-ipfix-middlebox]
Quittek, J., "Guidelines for IPFIX Implementations on Quittek, J., "Guidelines for IPFIX Implementations on
Middleboxes", draft-quittek-ipfix-middlebox-00 (work in Middleboxes", draft-quittek-ipfix-middlebox-00 (work in
progress), February 2004. progress), February 2004.
[RFC2678] Mahdavi, J. and V. Paxson, "IPPM Metrics for Measuring [RFC2678] Mahdavi, J. and V. Paxson, "IPPM Metrics for Measuring
Connectivity", RFC 2678, September 1999. Connectivity", RFC 2678, September 1999.
[RFC2681] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip [RFC2681] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip
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