< draft-gandhi-mpls-rfc6374-sr-02.txt   draft-gandhi-mpls-rfc6374-sr-03.txt >
MPLS Working Group R. Gandhi, Ed. MPLS Working Group R. Gandhi, Ed.
Internet-Draft C. Filsfils Internet-Draft C. Filsfils
Intended status: Standards Track Cisco Systems, Inc. Intended status: Standards Track Cisco Systems, Inc.
Expires: September 7, 2020 D. Voyer Expires: December 12, 2020 D. Voyer
Bell Canada Bell Canada
S. Salsano S. Salsano
Universita di Roma "Tor Vergata" Universita di Roma "Tor Vergata"
M. Chen M. Chen
Huawei Huawei
March 6, 2020 June 10, 2020
Performance Measurement for Segment Routing Networks with MPLS Data Performance Measurement Using RFC 6374 for Segment Routing Networks with
Plane MPLS Data Plane
draft-gandhi-mpls-rfc6374-sr-02 draft-gandhi-mpls-rfc6374-sr-03
Abstract Abstract
Segment Routing (SR) leverages the source routing paradigm. RFC 6374 Segment Routing (SR) leverages the source routing paradigm. RFC 6374
specifies protocol mechanisms to enable the efficient and accurate specifies protocol mechanisms to enable the efficient and accurate
measurement of packet loss, one-way and two-way delay, as well as measurement of packet loss, one-way and two-way delay, as well as
related metrics such as delay variation in MPLS networks using probe related metrics such as delay variation in MPLS networks using probe
messages. This document utilizes these mechanisms for Performance messages. This document utilizes these mechanisms for Performance
Delay and Loss Measurements in Segment Routing networks with MPLS Delay and Loss Measurements in Segment Routing networks with MPLS
data plane (SR-MPLS), for both SR Links and end-to-end SR Policies. data plane (SR-MPLS), for both SR Links and end-to-end SR Policies.
skipping to change at page 1, line 45 skipping to change at page 1, line 45
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 7, 2020. This Internet-Draft will expire on December 12, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4 2. Conventions Used in This Document . . . . . . . . . . . . . . 4
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Reference Topology . . . . . . . . . . . . . . . . . . . 5 2.3. Reference Topology . . . . . . . . . . . . . . . . . . . 5
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Probe Query and Response Messages . . . . . . . . . . . . . . 6 4. Probe Query and Response Messages . . . . . . . . . . . . . . 6
4.1. Probe Message for SR-MPLS Links . . . . . . . . . . . . . 6 4.1. Probe Message for SR Links . . . . . . . . . . . . . . . 6
4.2. Probe Message for SR-MPLS Policies . . . . . . . . . . . 6 4.2. Probe Message for SR Policies . . . . . . . . . . . . . . 6
4.3. Probe Response Message for SR-MPLS Links and Policies . . 7 4.3. Probe Response Message for SR Links and Policies . . . . 7
4.3.1. One-way Measurement Mode . . . . . . . . . . . . . . 7 4.3.1. One-way Measurement Mode . . . . . . . . . . . . . . 7
4.3.2. Two-way Measurement Mode . . . . . . . . . . . . . . 8 4.3.2. Two-way Measurement Mode . . . . . . . . . . . . . . 8
4.3.3. Loopback Measurement Mode . . . . . . . . . . . . . . 8 4.3.3. Loopback Measurement Mode . . . . . . . . . . . . . . 8
4.4. Return Path TLV . . . . . . . . . . . . . . . . . . . . . 8 4.4. Return Path TLV . . . . . . . . . . . . . . . . . . . . . 8
5. Performance Delay Measurement . . . . . . . . . . . . . . . . 10 5. Performance Delay Measurement . . . . . . . . . . . . . . . . 10
5.1. Delay Measurement Message Format . . . . . . . . . . . . 10 5.1. Delay Measurement Message Format . . . . . . . . . . . . 10
5.2. Timestamps . . . . . . . . . . . . . . . . . . . . . . . 10 5.2. Timestamps . . . . . . . . . . . . . . . . . . . . . . . 10
6. Performance Loss Measurement . . . . . . . . . . . . . . . . 10 6. Performance Loss Measurement . . . . . . . . . . . . . . . . 10
6.1. Loss Measurement Message Format . . . . . . . . . . . . . 11 6.1. Loss Measurement Message Format . . . . . . . . . . . . . 11
6.2. Block Number TLV . . . . . . . . . . . . . . . . . . . . 11 6.2. Block Number TLV . . . . . . . . . . . . . . . . . . . . 11
6.3. Combined Loss/Delay Measurement Message Format . . . . . 12
7. Performance Measurement for P2MP SR Policies . . . . . . . . 12 7. Performance Measurement for P2MP SR Policies . . . . . . . . 12
8. ECMP for SR-MPLS Policies . . . . . . . . . . . . . . . . . . 13 8. ECMP for SR Policies . . . . . . . . . . . . . . . . . . . . 13
9. SR Link Extended TE Metrics Advertisements . . . . . . . . . 13 9. SR Link Extended TE Metrics Advertisements . . . . . . . . . 13
10. Security Considerations . . . . . . . . . . . . . . . . . . . 14 10. Security Considerations . . . . . . . . . . . . . . . . . . . 14
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
12.1. Normative References . . . . . . . . . . . . . . . . . . 14 12.1. Normative References . . . . . . . . . . . . . . . . . . 15
12.2. Informative References . . . . . . . . . . . . . . . . . 15 12.2. Informative References . . . . . . . . . . . . . . . . . 16
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 17 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 18
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction 1. Introduction
Service provider's ability to satisfy Service Level Agreements (SLAs) Service provider's ability to satisfy Service Level Agreements (SLAs)
depend on the ability to measure and monitor performance metrics for depend on the ability to measure and monitor performance metrics for
packet loss and one-way and two-way delay, as well as related metrics packet loss and one-way and two-way delay, as well as related metrics
such as delay variation. The ability to monitor these performance such as delay variation. The ability to monitor these performance
metrics also provides operators with greater visibility into the metrics also provides operators with greater visibility into the
performance characteristics of their networks, thereby facilitating performance characteristics of their networks, thereby facilitating
planning, troubleshooting, and network performance evaluation. planning, troubleshooting, and network performance evaluation.
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defined in [RFC4656] and Two-Way Active Measurement Protocol (TWAMP) defined in [RFC4656] and Two-Way Active Measurement Protocol (TWAMP)
defined in [RFC5357] provide capabilities for the measurement of defined in [RFC5357] provide capabilities for the measurement of
various performance metrics in IP networks. However, mechanisms various performance metrics in IP networks. However, mechanisms
defined in [RFC6374] are more suitable for Segment Routing when using defined in [RFC6374] are more suitable for Segment Routing when using
MPLS data plane (SR-MPLS). [RFC6374] also supports "direct mode" MPLS data plane (SR-MPLS). [RFC6374] also supports "direct mode"
Loss Measurement (LM), which is required in SR networks. Loss Measurement (LM), which is required in SR networks.
[RFC7876] specifies the procedures to be used when sending and [RFC7876] specifies the procedures to be used when sending and
processing out-of-band performance measurement probe replies over an processing out-of-band performance measurement probe replies over an
UDP return path when receiving RFC 6374 based probe queries. These UDP return path when receiving RFC 6374 based probe queries. These
procedures can be used to send out-of-band PM replies for both SR- procedures can be used to send out-of-band PM replies for both SR
MPLS Links and Policies [I-D.ietf-spring-segment-routing-policy] for Links and Policies [I-D.ietf-spring-segment-routing-policy] for one-
one-way measurement. way measurement.
This document utilizes the probe-based mechanisms defined in This document utilizes the probe-based mechanisms defined in
[RFC6374] for Performance Delay and Loss Measurements in SR networks [RFC6374] for Performance Delay and Loss Measurements in SR networks
with MPLS data plane, for both SR Links and end-to-end SR Policies. with MPLS data plane, for both SR Links and end-to-end SR Policies.
In addition, this document defines Return Path TLV for two-way In addition, this document defines Return Path TLV for two-way
performance measurement and Block Number TLV for loss measurement. performance measurement and Block Number TLV for loss measurement.
The Performance Measurements (PM) for SR Links are used to compute The Performance Measurements (PM) for SR Links are used to compute
extended Traffic Engineering (TE) metrics for delay and loss and can extended Traffic Engineering (TE) metrics for delay and loss and can
be advertised in the network using the routing protocol extensions. be advertised in the network using the routing protocol extensions.
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SR-MPLS: Segment Routing with MPLS data plane. SR-MPLS: Segment Routing with MPLS data plane.
TC: Traffic Class. TC: Traffic Class.
TE: Traffic Engineering. TE: Traffic Engineering.
URO: UDP Return Object. URO: UDP Return Object.
2.3. Reference Topology 2.3. Reference Topology
In the reference topology shown in Figure 1, the sender node R1 In the reference topology shown in Figure 1, the querier node R1
initiates a performance measurement probe query and the responder initiates a performance measurement probe query and the responder
node R5 sends a probe response for the query message received. The node R5 sends a probe response for the query message received. The
probe response is typically sent back to the sender node R1. The probe response is typically sent back to the querier node R1. The
nodes R1 and R5 may be directly connected via a Link enabled with nodes R1 and R5 may be directly connected via a Link enabled with SR
Segment Routing or there exists a Point-to-Point (P2P) SR Policy or there exists a Point-to-Point (P2P) SR Path e.g. SR Policy
[I-D.ietf-spring-segment-routing-policy] on node R1 with destination [I-D.ietf-spring-segment-routing-policy] on node R1 with destination
to node R5. In case of Point-to-Multipoint (P2MP), SR Policy to node R5. In case of Point-to-Multipoint (P2MP), SR Policy
originating from source node R1 may terminate on multiple destination originating from source node R1 may terminate on multiple destination
leaf nodes [I-D.voyer-spring-sr-replication-segment]. leaf nodes [I-D.voyer-spring-sr-replication-segment]. In all cases,
the data plane has MPLS enabled on the nodes.
+-------+ t1 Query t2 +-------+ +-------+ t1 Query t2 +-------+
| | - - - - - - - - - ->| | | | - - - - - - - - - ->| |
| R1 |---------------------| R5 | | R1 |---------------------| R5 |
| |<- - - - - - - - - - | | | |<- - - - - - - - - - | |
+-------+ t4 Response t3 +-------+ +-------+ t4 Response t3 +-------+
Sender Responder Querier Responder
Figure 1: Reference Topology Figure 1: Reference Topology
3. Overview 3. Overview
One-way delay and two-way delay measurement procedure defined in One-way delay and two-way delay measurement procedure defined in
Section 2.4 of [RFC6374] are used. Transmit and Receive packet loss Section 2.4 of [RFC6374] are used. Transmit and Receive packet loss
measurement procedures defined in Section 2.2 and Section 2.6 of measurement procedures defined in Section 2.2 and Section 2.6 of
[RFC6374] are used. One-way loss measurement provides receive packet [RFC6374] are used. One-way loss measurement provides receive packet
loss whereas two-way loss measurement provides both transmit and loss whereas two-way loss measurement provides both transmit and
receive packet loss. For both SR Links and end-to-end SR Policies, receive packet loss. For both SR Links and end-to-end SR Policies,
no PM session for delay or loss measurement is created on the no PM session for delay or loss measurement is created on the
responder node R5 [RFC6374]. responder node R5 [RFC6374].
For Performance Measurement, probe query and response messages are For Performance Measurement, probe query and response messages are
sent as following: sent as following:
o For Delay Measurement, the probe messages are sent on the o For Delay Measurement, the probe messages are sent on the
congruent path of the data traffic by the sender node, and are congruent path of the data traffic by the querier node, and are
used to measure the delay experienced by the actual data traffic used to measure the delay experienced by the actual data traffic
flowing on the SR Links and SR Policies. flowing on the SR Links and SR Policies.
o For Loss Measurement, the probe messages are sent on the congruent o For Loss Measurement, the probe messages are sent on the congruent
path of the data traffic by the sender node, and are used to path of the data traffic by the querier node, and are used to
collect the receive traffic counters for the incoming link or collect the receive traffic counters for the incoming link or
incoming SID where the probe query messages are received at the incoming SID where the probe query messages are received at the
responder node (incoming link or incoming SID needed since the responder node (incoming link or incoming SID needed since the
responder node does not have PM session state present). responder node does not have PM session state present).
The In-Situ Operations, Administration, and Maintenance (IOAM) The In-Situ Operations, Administration, and Maintenance (IOAM)
mechanisms for SR-MPLS defined in [I-D.gandhi-mpls-ioam-sr] are used mechanisms for SR-MPLS defined in [I-D.gandhi-mpls-ioam-sr] are used
to carry PM information in-band as part of the data traffic packets, to carry PM information in-band as part of the data traffic packets,
and are outside the scope of this document. and are outside the scope of this document.
4. Probe Query and Response Messages 4. Probe Query and Response Messages
4.1. Probe Message for SR-MPLS Links 4.1. Probe Message for SR Links
As described in Section 2.9.1 of [RFC6374], MPLS PM probe query and As described in Section 2.9.1 of [RFC6374], probe query and response
response messages flow over the MPLS Generic Associated Channel messages flow over the MPLS Generic Associated Channel (G-ACh). A
(G-ACh). A probe message for SR-MPLS Links contains G-ACh Label probe message for SR Links contains G-ACh Label (GAL) (with S=1).
(GAL) (with S=1). The GAL is followed by an Associated Channel The GAL is followed by an Associated Channel Header (ACH), which
Header (ACH), which identifies the message type, and the message identifies the message type, and the message payload following the
payload following the ACH as shown in Figure 2. The probe messages ACH as shown in Figure 2. The probe messages are routed over the SR
are routed over the SR Links for both delay and loss measurement. Links for both delay and loss measurement. For SR Links, the TTL
For SR-MPLS Links, the TTL value is set to 1 in the SR-MPLS header value is set to 1 in the SR-MPLS header for one-way and two-way
for one-way and two-way measurement modes. measurement modes.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GAL (value 13) | TC |S| TTL | | GAL (value 13) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | GAL Channel Type | |0 0 0 1|Version| Reserved | GAL Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Probe Message Header for an SR-MPLS Link Figure 2: Probe Message Header for an SR Link
4.2. Probe Message for SR-MPLS Policies 4.2. Probe Message for SR Policies
As described in Section 2.9.1 of [RFC6374], MPLS PM probe query and As described in Section 2.9.1 of [RFC6374], probe query and response
response messages flow over the MPLS Generic Associated Channel messages flow over the MPLS Generic Associated Channel (G-ACh). A
(G-ACh). A probe message for an end-to-end measurement for SR Policy probe message for an end-to-end SR Policy measurement contains SR-
contains SR-MPLS label stack MPLS label stack [I-D.ietf-spring-segment-routing-policy], with the
[I-D.ietf-spring-segment-routing-policy], with the G-ACh Label (GAL) G-ACh Label (GAL) at the bottom of the stack (with S=1). The GAL is
at the bottom of the stack (with S=1). The GAL is followed by an followed by an Associated Channel Header (ACH), which identifies the
Associated Channel Header (ACH), which identifies the message type, message type, and the message payload following the ACH as shown in
and the message payload following the ACH as shown in Figure 3. For Figure 3. For SR Policies, the TTL value is set to 255 in the SR-
SR-MPLS Policies, the TTL value is set to 255 in the SR-MPLS header. MPLS header.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label(1) | TC |S| TTL | | Label(1) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . . .
. . . .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label(n) | TC |S| TTL | | Label(n) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GAL (value 13) | TC |S| TTL | | GAL (value 13) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | GAL Channel Type | |0 0 0 1|Version| Reserved | GAL Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Probe Message Header for an End-to-end SR-MPLS Policy Figure 3: Example Probe Message Header for an End-to-end SR Policy
The SR-MPLS label stack can be empty (as shown in Figure 2) to The SR-MPLS label stack can be empty (as shown in Figure 2) to
indicate Implicit NULL label case. indicate Implicit NULL label case.
For SR Policy performance measurement, in order to ensure that the For SR Policy performance measurement, in order to ensure that the
probe query message is processed by the intended responder node, probe query message is processed by the intended responder node,
Destination Address TLV (Type 129) [RFC6374] can be sent in the probe Destination Address TLV (Type 129) [RFC6374] can be sent in the probe
query message. The responder node only replies with Success in query message. The responder node only replies with Success in
Control Code if it is the intended destination for the probe query. Control Code if it is the intended destination for the probe query.
Otherwise, it MUST return 0x15: Error - Invalid Destination Node Otherwise, it MUST return 0x15: Error - Invalid Destination Node
Identifier. Identifier [RFC6374].
4.3. Probe Response Message for SR-MPLS Links and Policies 4.3. Probe Response Message for SR Links and Policies
4.3.1. One-way Measurement Mode 4.3.1. One-way Measurement Mode
In one-way performance measurement mode [RFC7679], the PM sender node In one-way performance measurement mode [RFC7679], the querier node
can receive "out-of-band" probe replies by properly setting the UDP can receive "out-of-band" probe replies by properly setting the UDP
Return Object (URO) TLV in the probe query message. The URO TLV Return Object (URO) TLV in the probe query message. The URO TLV
(Type=131) is defined in [RFC7876] and includes the UDP-Destination- (Type=131) is defined in [RFC7876] and includes the UDP-Destination-
Port and IP Address. In particular, if the sender sets its own IP Port and IP Address. In particular, if the querier node sets its own
address in the URO TLV, the probe response is sent back by the IP address in the URO TLV, the probe response is sent back by the
responder node to the sender node. In addition, the "control code" responder node to the querier node. In addition, the "control code"
in the probe query message is set to "out-of-band response in the probe query message is set to "out-of-band response
requested". In this delay measurement mode, as per Reference requested". In this delay measurement mode, as per Reference
Topology, timestamps t1 and t2 are collected by the probes. Only Topology, timestamps t1 and t2 are collected by the probes. Only
timestamps t1 and t2 are used to measure one-way delay. The one-way timestamps t1 and t2 are used to measure one-way delay. The one-way
mode is applicable to both SR-MPLS Links and SR-MPLS Policies. mode is applicable to both SR Links and Policies.
4.3.2. Two-way Measurement Mode 4.3.2. Two-way Measurement Mode
In two-way performance measurement mode [RFC6374], when using a In two-way performance measurement mode [RFC6374], when using a
bidirectional path, the probe response message is sent back to the bidirectional path, the probe response message is sent back to the
sender node on the congruent path of the data traffic on the reverse querier node on the congruent path of the data traffic on the reverse
direction SR Link or associated SR Policy direction SR Link or associated SR Policy
[I-D.ietf-pce-sr-bidir-path] using a message with format similar to [I-D.ietf-pce-sr-bidir-path] using a message with format similar to
their probe query message. In this case, the "control code" in the their probe query message. In this case, the "control code" in the
probe query message is set to "in-band response requested". In this probe query message is set to "in-band response requested". In this
delay measurement mode, as per Reference Topology, all timestamps t1, delay measurement mode, as per Reference Topology, all timestamps t1,
t2, t3, and t4 are collected by the probes. All four timestamps are t2, t3, and t4 are collected by the probes. All four timestamps are
used to measure two-way delay. The two-way mode is applicable to used to measure two-way delay. The two-way mode is applicable to
both SR-MPLS Links and SR-MPLS Policies. both SR Links and Policies.
Specifically, the probe response message is sent back on the incoming Specifically, the probe response message is sent back on the incoming
physical interface where the probe query message is received. This physical interface where the probe query message is received. This
is useful for example, in case of two-way measurement mode for Link is useful for example, in case of two-way measurement mode for Link
delay. delay.
The Path Segment Identifier (PSID) The Path Segment Identifier (PSID)
[I-D.ietf-spring-mpls-path-segment] of the forward SR-MPLS Policy in [I-D.ietf-spring-mpls-path-segment] of the forward SR Policy in the
the probe query can be used to find the associated reverse SR Policy probe query can be used to find the associated reverse SR Policy
[I-D.ietf-pce-sr-bidir-path] to send the probe response message for [I-D.ietf-pce-sr-bidir-path] to send the probe response message for
two-way measurement of SR-MPLS Policy unless when using the Return two-way measurement of SR Policy unless when using the Return Path
Path TLV. TLV.
4.3.3. Loopback Measurement Mode 4.3.3. Loopback Measurement Mode
The Loopback measurement mode defined in Section 2.8 of [RFC6374] can The Loopback measurement mode defined in Section 2.8 of [RFC6374] can
be used to measure round-trip delay for a bidirectional SR Path be used to measure round-trip delay for a bidirectional SR Path
[I-D.ietf-pce-sr-bidir-path]. The probe query messages in this case [I-D.ietf-pce-sr-bidir-path]. The probe query messages in this case
carries the reverse SR Path label stack as part of the MPLS header. carries the reverse SR Path label stack as part of the MPLS header.
The GAL is still carried at the bottom of the label stack (with S=1). The GAL is still carried at the bottom of the label stack (with S=1).
The responder node does not process the PM probe messages and The responder node does not process the probe messages and generate
generate response messages. In this delay measurement mode, as per response messages, and hence Loopback Request object (Type 3) is not
Reference Topology, the timestamps t1 and t4 are collected by the required for SR. In this delay measurement mode, as per Reference
probes. Both these timestamps are used to measure round-trip delay. Topology, the timestamps t1 and t4 are collected by the probes. Both
The loopback mode for SR-MPLS Links is outside the scope of this these timestamps are used to measure round-trip delay. The loopback
document. mode for SR Links is outside the scope of this document.
4.4. Return Path TLV 4.4. Return Path TLV
For two-way performance measurement, the responder node needs to send For two-way performance measurement, the responder node needs to send
the probe response message on a specific reverse path. The sender the probe response message on a specific reverse path. The querier
node can request in the probe query message to the responder node to node can request in the probe query message to the responder node to
send a response message back on a given reverse path (e.g. co-routed send a response message back on a given reverse path (e.g. co-routed
path for two-way measurement). This way the destination node does path for two-way measurement). This way the destination node does
not require any additional SR Policy state. not require any additional SR Policy state.
For one-way performance measurement, the sender node address may not For one-way performance measurement, the querier node address may not
be reachable via IP route from the responder node. The sender node be reachable via IP route from the responder node. The querier node
in this case needs to send its reachability path information to the in this case needs to send its reachability path information to the
responder node. responder node.
[RFC6374] defines DM and LM probe query messages that can include one [RFC6374] defines DM and LM probe query messages that can include one
or more optional TLVs. New TLV Type (TBA1) is defined in this or more optional TLVs. New TLV Type (TBA1) is defined in this
document for Return Path to carry reverse path for probe response document for Return Path to carry reverse path for probe response
messages (in the payload of the message). The format of the Return messages (in the payload of the message). The format of the Return
Path TLV is shown in Figure 4 and Figure 5: Path TLV is shown in Figure 4 and Figure 5:
0 1 2 3 0 1 2 3
skipping to change at page 10, line 7 skipping to change at page 10, line 7
Figure 5: Segment List Sub-TLV in Return Path TLV Figure 5: Segment List Sub-TLV in Return Path TLV
The Segment List Sub-TLV in the Return Path TLV can be one of the The Segment List Sub-TLV in the Return Path TLV can be one of the
following Types: following Types:
o Type (value 1): SR-MPLS Label Stack of the Reverse SR Path o Type (value 1): SR-MPLS Label Stack of the Reverse SR Path
o Type (value 2): SR-MPLS Binding SID o Type (value 2): SR-MPLS Binding SID
[I-D.ietf-pce-binding-label-sid] of the Reverse SR Policy [I-D.ietf-pce-binding-label-sid] of the Reverse SR Policy
The Return Path TLV is Mandatory when used. If responder does not The Return Path TLV is Mandatory when carried in a probe query
support this TLV, it MUST return Error 0x17: Unsupported Mandatory message. If responder does not support this TLV, it MUST return
TLV Object. The PM sender node MUST only insert one Return Path TLV Error 0x17: Unsupported Mandatory TLV Object. The querier node MUST
in the probe query message and the responder node MUST only process only insert one Return Path TLV in the probe query message and the
the first Return Path TLV in the probe query message and ignore other responder node MUST only process the first Return Path TLV in the
Return Path TLVs if present. The responder node MUST send probe probe query message and ignore other Return Path TLVs if present.
response message back on the reverse path specified in the Return The responder node MUST send probe response message back on the
Path TLV and MUST NOT add Return Path TLV in the probe response reverse path specified in the Return Path TLV and MUST NOT add Return
message. Path TLV in the probe response message.
5. Performance Delay Measurement 5. Performance Delay Measurement
5.1. Delay Measurement Message Format 5.1. Delay Measurement Message Format
As defined in [RFC6374], MPLS DM probe query and response messages As defined in [RFC6374], MPLS DM probe query and response messages
use Associated Channel Header (ACH) (value 0x000C for delay use Associated Channel Header (ACH) (value 0x000C for delay
measurement) [RFC6374], which identifies the message type, and the measurement) [RFC6374], which identifies the message type, and the
message payload following the ACH. For both SR Links and end-to-end message payload following the ACH. For both SR Links and end-to-end
measurement for SR-MPLS Policies, the same MPLS DM ACH value is used. SR Policies measurements, the same MPLS DM ACH value can be used.
The DM message payload as defined in Section 3.2 of [RFC6374] is used The DM message payload as defined in Section 3.2 of [RFC6374] is used
for SR-MPLS delay measurement, for both SR Links and end-to-end SR for SR-MPLS delay measurement, for both SR Links and end-to-end SR
Policies. Policies.
5.2. Timestamps 5.2. Timestamps
The Section 3.4 of [RFC6374] defines timestamp format that can be The Section 3.4 of [RFC6374] defines timestamp format that can be
used for delay measurement. The IEEE 1588 Precision Time Protocol used for delay measurement. The IEEE 1588 Precision Time Protocol
(PTP) timestamp format [IEEE1588] is used by default as described in (PTP) timestamp format [IEEE1588] is used by default as described in
skipping to change at page 11, line 7 skipping to change at page 11, line 7
test messages in order to infer the approximate data plane loss test messages in order to infer the approximate data plane loss
level. Inferred mode LM provides only approximate loss level. Inferred mode LM provides only approximate loss
accounting. accounting.
o In direct mode, LM will directly measure data plane packet loss. o In direct mode, LM will directly measure data plane packet loss.
Direct mode LM provides perfect loss accounting, but may require Direct mode LM provides perfect loss accounting, but may require
hardware support. hardware support.
For both of these modes of LM, Path Segment Identifier (PSID) For both of these modes of LM, Path Segment Identifier (PSID)
[I-D.ietf-spring-mpls-path-segment] is used for accounting received [I-D.ietf-spring-mpls-path-segment] is used for accounting received
traffic on the egress node of the SR-MPLS Policy as shown in traffic on the egress node of the SR Policy as shown in Figure 6.
Figure 6. Different values of PSID can be used to measure packet Different values of PSID can be used to measure packet loss per SR
loss per SR-MPLS Policy, per Candidate Path or per Segment List of Policy, per Candidate Path or per Segment List of the SR Policy.
the SR Policy.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PSID | TC |S| TTL | | PSID | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GAL (value 13) | TC |S| TTL | | GAL (value 13) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | GAL Channel Type | |0 0 0 1|Version| Reserved | GAL Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: With Path Segment Identifier for SR-MPLS Policy Figure 6: Example With Path Segment Identifier for SR Policy
6.1. Loss Measurement Message Format 6.1. Loss Measurement Message Format
As defined in [RFC6374], MPLS LM probe query and response messages As defined in [RFC6374], MPLS LM probe query and response messages
use Associated Channel Header (ACH) (value 0x000A for direct loss use Associated Channel Header (ACH) (value 0x000A for direct loss
measurement or value 0x000B for inferred loss measurement), which measurement or value 0x000B for inferred loss measurement), which
identifies the message type, and the message payload following the identifies the message type, and the message payload following the
ACH. For both SR Links and end-to-end measurement for SR-MPLS ACH. For both SR Links and end-to-end SR Policies measurements, the
Policies, the same MPLS LM ACH value is used. same MPLS LM ACH value can be used.
The LM message payload as defined in Section 3.1 of [RFC6374] is used The LM message payload as defined in Section 3.1 of [RFC6374] is used
for SR-MPLS loss measurement, for both SR Links and end-to-end SR for SR-MPLS loss measurement, for both SR Links and end-to-end SR
Policies. Policies.
6.2. Block Number TLV 6.2. Block Number TLV
The Loss Measurement using Alternate-Marking method defined in The Loss Measurement using Alternate-Marking method defined in
[RFC8321] requires to color the data traffic. To be able to compare [RFC8321] requires to color the data traffic. To be able to
the transmit and receive traffic counters of the matching color, the correlate the transmit and receive traffic counters of the matching
Block Number (or color) of the traffic counters is carried by the color, the Block Number (or color) of the traffic counters is carried
probe query and response messages for loss measurement. Probe query by the probe query and response messages for loss measurement. The
and response messages specified in [RFC6374] for Loss Measurement do probe query and response messages currently specified in [RFC6374]
not identify the Block Number of the counters. for Loss Measurement do not identify the Block Number of the
counters. The Block Number can also be used to aggregate performance
metrics collected.
[RFC6374] defines probe query and response messages that can include [RFC6374] defines probe query and response messages that can include
one or more optional TLVs. New TLV Type (value TBA2) is defined in one or more optional TLVs. New TLV Type (value TBA2) is defined in
this document to carry the Block Number (8-bit) of the traffic this document to carry the Block Number (8-bit) of the traffic
counters in the probe query and response messages for loss counters in the probe query and response messages for loss
measurement. The format of the Block Number TLV is shown in measurement. The format of the Block Number TLV is shown in
Figure 7: Figure 7:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type TBA2 | Length | Reserved | Block Number | | Type TBA2 | Length | Reserved | Block Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Block Number TLV Figure 7: Block Number TLV
The Block Number TLV is Mandatory when used. If responder does not The Block Number TLV is Mandatory when carried in a probe query
support this TLV, it MUST return Error 0x17: Unsupported Mandatory message. If responder does not support this TLV, it MUST return
TLV Object. The PM sender node SHOULD only insert one Block Number Error 0x17: Unsupported Mandatory TLV Object. The querier node
TLV in the probe query message and the responder node in the probe SHOULD only insert one Block Number TLV in the probe query message
response message SHOULD return the first Block Number TLV from the and the responder node in the probe response message SHOULD return
probe query messages and ignore other Block Number TLVs if present. the first Block Number TLV from the probe query messages and ignore
In probe messages, the counters MUST belong to the same Block Number. other Block Number TLVs if present. In probe messages, the counters
MUST belong to the same Block Number.
6.3. Combined Loss/Delay Measurement Message Format
As defined in [RFC6374], Combined DM+LM probe query and response
messages use Associated Channel Header (ACH) (value 0x000D for direct
loss and delay measurement or value 0x000E for inferred loss and
delay measurement), which identifies the message type, and the
message payload following the ACH. For both SR Links and end-to-end
SR Policies measurements, the same MPLS ACH value can be used.
The message payload as defined in Section 3.3 of [RFC6374] is used
for SR-MPLS combined delay and loss measurement, for both SR Links
and end-to-end SR Policies.
7. Performance Measurement for P2MP SR Policies 7. Performance Measurement for P2MP SR Policies
The procedures for delay and loss measurement described in this The procedures for one-way delay and loss measurement described in
document for Point-to-Point (P2P) SR-MPLS Policies this document for Point-to-Point (P2P) SR Policies
[I-D.ietf-spring-segment-routing-policy] are also equally applicable [I-D.ietf-spring-segment-routing-policy] are also equally applicable
to the Point-to-Multipoint (P2MP) SR-MPLS Policies as following: to the Point-to-Multipoint (P2MP) SR Policies as following:
o The sender root node sends probe query messages using the o The querier root node sends probe query messages using the
Replication Segment defined in Replication Segment defined in
[I-D.voyer-spring-sr-replication-segment] for the P2MP SR Policy [I-D.voyer-spring-sr-replication-segment] for the P2MP SR Policy
as shown in Figure 8. as shown in Figure 8.
o Each responder leaf node adds the "Source Address" TLV (Type 130) o Each responder leaf node adds the "Source Address" TLV (Type 130)
[RFC6374] with its IP address in the probe response messages. [RFC6374] with its IP address in the probe response messages.
This TLV allows the sender root node to identify the responder
This TLV allows the querier root node to identify the responder
leaf nodes of the P2MP SR Policy. leaf nodes of the P2MP SR Policy.
o The P2MP root node measures the end-to-end delay and loss o The P2MP root node measures the end-to-end delay and loss
performance for each P2MP leaf node of the P2MP SR Policy. performance for each P2MP leaf node of the P2MP SR Policy.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Replication SID | TC |S| TTL | | Replication SID | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GAL (value 13) | TC |S| TTL | | GAL (value 13) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | GAL Channel Type | |0 0 0 1|Version| Reserved | GAL Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Query with Replication Segment for SR-MPLS Policy Figure 8: Example Probe Query with Replication Segment for SR Policy
8. ECMP for SR-MPLS Policies The considerations for two-way and loopback modes for performance
measurement for P2MP SR Policy are outside the scope of this
document.
8. ECMP for SR Policies
An SR Policy can have ECMPs between the source and transit nodes, An SR Policy can have ECMPs between the source and transit nodes,
between transit nodes and between transit and destination nodes. between transit nodes and between transit and destination nodes.
Usage of Anycast SID [RFC8402] by an SR Policy can result in ECMP Usage of Anycast SID [RFC8402] by an SR Policy can result in ECMP
paths via transit nodes part of that Anycast group. The PM probe paths via transit nodes part of that Anycast group. The probe
messages need to be sent to traverse different ECMP paths to measure messages need to be sent to traverse different ECMP paths to measure
performance delay of each of the ECMP path of an SR Policy. performance delay of each of the ECMP path of an SR Policy.
Forwarding plane has various hashing functions available to forward Forwarding plane has various hashing functions available to forward
packets on specific ECMP paths. For SR-MPLS Policy, sweeping of packets on specific ECMP paths. For SR Policy, sweeping of entropy
entropy label [RFC6790] values can be used in PM probe messages to label [RFC6790] values can be used in probe messages to take
take advantage of the hashing function in forwarding plane to advantage of the hashing function in forwarding plane to influence
influence the ECMP path taken by them. the ECMP path taken by them.
The considerations for performance loss measurement for different The considerations for performance loss measurement for different
ECMP paths of an SR Policy are outside the scope of this document. ECMP paths of an SR Policy are outside the scope of this document.
9. SR Link Extended TE Metrics Advertisements 9. SR Link Extended TE Metrics Advertisements
The extended TE metrics for SR Link delay and loss computed using the The extended TE metrics for SR Link delay and loss computed using the
performance measurement procedures described in this document can be performance measurement procedures described in this document can be
advertised in the routing domain as follows: advertised in the routing domain as follows:
skipping to change at page 14, line 22 skipping to change at page 14, line 33
This document describes the procedures for performance delay and loss This document describes the procedures for performance delay and loss
measurement for SR-MPLS networks, for both SR Links and end-to-end SR measurement for SR-MPLS networks, for both SR Links and end-to-end SR
Policies using the mechanisms defined in [RFC6374] and [RFC7876]. Policies using the mechanisms defined in [RFC6374] and [RFC7876].
This document does not introduce any additional security This document does not introduce any additional security
considerations other than those covered in [RFC6374], [RFC7471], considerations other than those covered in [RFC6374], [RFC7471],
[RFC8570], [RFC8571], and [RFC7876]. [RFC8570], [RFC8571], and [RFC7876].
11. IANA Considerations 11. IANA Considerations
IANA is requested to allocate a value for the following mandatory IANA is requested to allocate a value for the following mandatory
Return Path TLV Type for RFC 6374 to be carried in PM probe query Return Path TLV Type for [RFC6374] to be carried in probe query
messages: message from the "MPLS Loss/Delay Measurement TLV Object" registry
contained within the "Generic Associated Channel (G-ACh) Parameters"
registry set:
o Type TBA1: Return Path TLV o Type TBA1: Return Path TLV
IANA is requested to create a sub-registry for "Return Path Sub-TLV
Type" for the Return Path TLV. All code points in the range 1
through 32759 in this registry shall be allocated according to the
"IETF Review" procedure as specified in [RFC8126]. Code points in
the range 32760 through 65279 in this registry shall be allocated
according to the "First Come First Served" procedure as specified in
[RFC8126]. Remaining code points are allocated according to Table 1:
+---------------+-------------------------+-------------------------+
| Value | Description | Reference |
+---------------+-------------------------+-------------------------+
| 0- 32767 | Mandatory TLV, | IETF Review |
| | unassigned | |
| 32768 - 65279 | Optional TLV, | First Come First Served |
| | unassigned | |
| 65280 - 65519 | Experimental | This document |
| 65520 - 65534 | Private Use | This document |
| 65535 | Reserved | This document |
+---------------+-------------------------+-------------------------+
Table 1: Return Path Sub-TLV Type Registry
IANA is requested to allocate the values for the following Sub-TLV IANA is requested to allocate the values for the following Sub-TLV
Types for the Return Path TLV for RFC 6374. Types from this registry.
o Type (value 1): SR-MPLS Label Stack of the Reverse SR Path o Type (value 1): SR-MPLS Label Stack of the Reverse SR Path
o Type (value 2): SR-MPLS Binding SID o Type (value 2): SR-MPLS Binding SID
[I-D.ietf-pce-binding-label-sid] of the Reverse SR Policy [I-D.ietf-pce-binding-label-sid] of the Reverse SR Policy
IANA is also requested to allocate a value for the following IANA is also requested to allocate a value for the following
mandatory Block Number TLV Type for RFC 6374 to be carried in the PM mandatory Block Number TLV Type for RFC 6374 to be carried in the
probe query and response messages for loss measurement: probe query and response messages for loss measurement from the "MPLS
Loss/Delay Measurement TLV Object" registry contained within the
"Generic Associated Channel (G-ACh) Parameters" registry set:
o Type TBA2: Block Number TLV o Type TBA2: Block Number TLV
12. References 12. References
12.1. Normative References 12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
skipping to change at page 16, line 10 skipping to change at page 16, line 45
[RFC7679] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, [RFC7679] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
Ed., "A One-Way Delay Metric for IP Performance Metrics Ed., "A One-Way Delay Metric for IP Performance Metrics
(IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January (IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January
2016, <https://www.rfc-editor.org/info/rfc7679>. 2016, <https://www.rfc-editor.org/info/rfc7679>.
[RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. [RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S.
Previdi, "OSPF Traffic Engineering (TE) Metric Previdi, "OSPF Traffic Engineering (TE) Metric
Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015,
<https://www.rfc-editor.org/info/rfc7471>. <https://www.rfc-editor.org/info/rfc7471>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
"Alternate-Marking Method for Passive and Hybrid "Alternate-Marking Method for Passive and Hybrid
Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
January 2018, <https://www.rfc-editor.org/info/rfc8321>. January 2018, <https://www.rfc-editor.org/info/rfc8321>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>. July 2018, <https://www.rfc-editor.org/info/rfc8402>.
skipping to change at page 16, line 40 skipping to change at page 17, line 35
<https://www.rfc-editor.org/info/rfc8571>. <https://www.rfc-editor.org/info/rfc8571>.
[RFC8668] Ginsberg, L., Ed., Bashandy, A., Filsfils, C., Nanduri, [RFC8668] Ginsberg, L., Ed., Bashandy, A., Filsfils, C., Nanduri,
M., and E. Aries, "Advertising Layer 2 Bundle Member Link M., and E. Aries, "Advertising Layer 2 Bundle Member Link
Attributes in IS-IS", RFC 8668, DOI 10.17487/RFC8668, Attributes in IS-IS", RFC 8668, DOI 10.17487/RFC8668,
December 2019, <https://www.rfc-editor.org/info/rfc8668>. December 2019, <https://www.rfc-editor.org/info/rfc8668>.
[I-D.ietf-spring-segment-routing-policy] [I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Sivabalan, S., Voyer, D., Bogdanov, A., and Filsfils, C., Sivabalan, S., Voyer, D., Bogdanov, A., and
P. Mattes, "Segment Routing Policy Architecture", draft- P. Mattes, "Segment Routing Policy Architecture", draft-
ietf-spring-segment-routing-policy-06 (work in progress), ietf-spring-segment-routing-policy-07 (work in progress),
December 2019. May 2020.
[I-D.voyer-spring-sr-replication-segment] [I-D.voyer-spring-sr-replication-segment]
Voyer, D., Filsfils, C., Parekh, R., Bidgoli, H., and Z. Voyer, D., Filsfils, C., Parekh, R., Bidgoli, H., and Z.
Zhang, "SR Replication Segment for Multi-point Service Zhang, "SR Replication Segment for Multi-point Service
Delivery", draft-voyer-spring-sr-replication-segment-02 Delivery", draft-voyer-spring-sr-replication-segment-03
(work in progress), November 2019. (work in progress), June 2020.
[I-D.ietf-pce-binding-label-sid] [I-D.ietf-pce-binding-label-sid]
Sivabalan, S., Filsfils, C., Tantsura, J., Hardwick, J., Sivabalan, S., Filsfils, C., Tantsura, J., Hardwick, J.,
Previdi, S., and C. Li, "Carrying Binding Label/Segment-ID Previdi, S., and C. Li, "Carrying Binding Label/Segment-ID
in PCE-based Networks.", draft-ietf-pce-binding-label- in PCE-based Networks.", draft-ietf-pce-binding-label-
sid-01 (work in progress), November 2019. sid-02 (work in progress), March 2020.
[I-D.ietf-spring-mpls-path-segment] [I-D.ietf-spring-mpls-path-segment]
Cheng, W., Li, H., Chen, M., Gandhi, R., and R. Zigler, Cheng, W., Li, H., Chen, M., Gandhi, R., and R. Zigler,
"Path Segment in MPLS Based Segment Routing Network", "Path Segment in MPLS Based Segment Routing Network",
draft-ietf-spring-mpls-path-segment-02 (work in progress), draft-ietf-spring-mpls-path-segment-02 (work in progress),
February 2020. February 2020.
[I-D.gandhi-mpls-ioam-sr] [I-D.gandhi-mpls-ioam-sr]
Gandhi, R., Ali, Z., Filsfils, C., Brockners, F., Wen, B., Gandhi, R., Ali, Z., Filsfils, C., Brockners, F., Wen, B.,
and V. Kozak, "Segment Routing with MPLS Data Plane and V. Kozak, "MPLS Data Plane Encapsulation for In-situ
Encapsulation for In-situ OAM Data", draft-gandhi-mpls- OAM Data", draft-gandhi-mpls-ioam-sr-02 (work in
ioam-sr-01 (work in progress), December 2019. progress), March 2020.
[I-D.ketant-lsr-ospf-l2bundles] [I-D.ketant-lsr-ospf-l2bundles]
Talaulikar, K. and P. Psenak, "Advertising L2 Bundle Talaulikar, K. and P. Psenak, "Advertising L2 Bundle
Member Link Attributes in OSPF", draft-ketant-lsr-ospf- Member Link Attributes in OSPF", draft-ketant-lsr-ospf-
l2bundles-01 (work in progress), January 2020. l2bundles-01 (work in progress), January 2020.
[I-D.ietf-pce-sr-bidir-path] [I-D.ietf-pce-sr-bidir-path]
Li, C., Chen, M., Cheng, W., Gandhi, R., and Q. Xiong, Li, C., Chen, M., Cheng, W., Gandhi, R., and Q. Xiong,
"PCEP Extensions for Associated Bidirectional Segment "PCEP Extensions for Associated Bidirectional Segment
Routing (SR) Paths", draft-ietf-pce-sr-bidir-path-01 (work Routing (SR) Paths", draft-ietf-pce-sr-bidir-path-02 (work
in progress), February 2020. in progress), March 2020.
Acknowledgments Acknowledgments
The authors would like to thank Thierry Couture for the discussions The authors would like to thank Thierry Couture for the discussions
on the use-cases for the performance measurement in segment routing on the use-cases for the performance measurement in segment routing
networks. Authors would like to thank Patrick Khordoc for networks. Authors would like to thank Patrick Khordoc for
implementing the mechanisms defined in this document. The authors implementing the mechanisms defined in this document. The authors
would like to thank Greg Mirsky for providing many useful comments would like to thank Greg Mirsky for providing many useful comments
and suggestions. The authors would also like to thank Stewart and suggestions. The authors would also like to thank Stewart
Bryant, Sam Aldrin, Tarek Saad, and Rajiv Asati for their review Bryant, Sam Aldrin, Tarek Saad, and Rajiv Asati for their review
comments. comments. Thanks to Huaimo Chen for MPLS-RT expert review.
Contributors Contributors
Sagar Soni Sagar Soni
Cisco Systems, Inc. Cisco Systems, Inc.
Email: sagsoni@cisco.com Email: sagsoni@cisco.com
Zafar Ali Zafar Ali
Cisco Systems, Inc. Cisco Systems, Inc.
Email: zali@cisco.com Email: zali@cisco.com
Pier Luigi Ventre Pier Luigi Ventre
CNIT CNIT
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