Enhanced Performance Measurement Using Simple TWAMP in Segment Routing Networks
draft-gandhi-spring-enhanced-srpm-01
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Rakesh Gandhi , Clarence Filsfils , Navin Vaghamshi , Moses Nagarajah , Richard "Footer" Foote , Mach Chen , Amit Dhamija | ||
| Last updated | 2022-02-15 (Latest revision 2021-08-24) | ||
| Replaces | draft-gandhi-spring-sr-enhanced-plm | ||
| Replaced by | draft-ietf-spring-stamp-srpm | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
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| Send notices to | (None) |
draft-gandhi-spring-enhanced-srpm-01
SPRING Working Group R. Gandhi, Ed.
Internet-Draft C. Filsfils
Intended status: Standards Track Cisco Systems, Inc.
Expires: 19 August 2022 N. Vaghamshi
Reliance
M. Nagarajah
Telstra
R. Foote
Nokia
M. Chen
Huawei
A. Dhamija
Rakuten
15 February 2022
Enhanced Performance Measurement Using Simple TWAMP in Segment Routing
Networks
draft-gandhi-spring-enhanced-srpm-01
Abstract
Segment Routing (SR) leverages the source routing paradigm. SR is
applicable to both Multiprotocol Label Switching (SR-MPLS) and IPv6
(SRv6) data planes. This document defines procedure for Enhanced
Performance Measurement of end-to-end SR paths including SR Policies
for both SR-MPLS and SRv6 data planes using Simple Two-Way Active
Measurement Protocol (STAMP) defined in RFC 8762. The procedure
reduces the deployment and operational complexities in a network.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 19 August 2022.
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Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Reference Topology . . . . . . . . . . . . . . . . . . . 5
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Enhanced Loopback Mode Enabled with Network Programming
Function . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Example Provisioning Model . . . . . . . . . . . . . . . 6
4. Enhanced Performance Measurement Procedure . . . . . . . . . 7
4.1. Enhanced Performance Measurement Procedure for SR-MPLS
Policies . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1.1. Timestamp Label Allocation . . . . . . . . . . . . . 9
4.1.2. Node Capability for Timestamp Label . . . . . . . . . 9
4.2. Enhanced Performance Measurement Procedure for SRv6
Policies . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2.1. Timestamp Endpoint Function Assignment . . . . . . . 11
4.2.2. Node Capability for Timestamp Endpoint Function . . . 12
5. Example Failure Notifications . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . 15
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
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1. Introduction
Segment Routing (SR) leverages the source routing paradigm and
greatly simplifies network operations for Software Defined Networks
(SDNs). SR is applicable to both Multiprotocol Label Switching (SR-
MPLS) and IPv6 (SRv6) data planes [RFC8402]. SR Policies as defined
in [I-D.ietf-spring-segment-routing-policy] are used to steer traffic
through a specific, user-defined paths using a stack of Segments. A
comprehensive SR Performance Measurement (PM) for delay and packet
loss as well as Connectivity Verification (CV) is one of the
essential requirements to measure network performance to provide
Service Level Agreements (SLAs).
The Simple Two-Way Active Measurement Protocol (STAMP) provides
capabilities for the measurement of various performance metrics in IP
networks [RFC8762] without the use of a control channel to pre-signal
session parameters. As described in [I-D.ietf-spring-stamp-srpm],
STAMP can be used for performance measurement for delay and packet
loss of end-to-end SR paths.
Seamless Bidirectional Forwarding Detection (S-BFD) [RFC7880]
provides a simplified mechanism for using BFD for path monitoring
with a large proportion of negotiation aspects eliminated. The S-BFD
can be used for connectivity verification of end-to-end SR paths.
Both STAMP and S-BFD require protocol support on the far-end
Reflector node to process the received packets, and hence the
received packets need to be punted from the forwarding fast path and
return packets need to be generated. This limits the scale for
number sessions and the ability to provide faster detection interval.
Enabling multiple protocols, S-BFD for connectivity verification and
STAMP for performance measurement increases the deployment and
operational complexities in a network. Also, implementing multiple
protocols in a hardware significantly increases the development cost.
This document defines procedure for Enhanced Performance Measurement
of end-to-end SR paths including SR Policies for both SR-MPLS and
SRv6 data planes, using Simple Two-Way Active Measurement Protocol
(STAMP) defined in [RFC8762]. The procedure reduces the deployment
and operational complexities in a network.
2. Conventions Used in This Document
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2.1. Requirements Language
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 [RFC2119] [RFC8174]
when, and only when, they appear in all capitals, as shown here.
2.2. Abbreviations
S-BFD: Seamless Bidirectional Forwarding Detection.
BSID: Binding Segment ID.
ECMP: Equal Cost Multi-Path.
EB: Endpoint Behaviour.
HMAC: Hashed Message Authentication Code.
MBZ: Must be Zero.
MPLS: Multiprotocol Label Switching.
PM: Performance Measurement.
PTP: Precision Time Protocol.
SID: Segment ID.
SL: Segment List.
SR: Segment Routing.
SRH: Segment Routing Header.
SR-MPLS: Segment Routing with MPLS data plane.
SRv6: Segment Routing with IPv6 data plane.
STAMP: Simple Two-way Active Measurement Protocol.
TC: Traffic Class.
TTL: Time To Live.
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2.3. Reference Topology
In the reference topology shown in Figure 1, the STAMP Session-Sender
[RFC8762] S1 initiates a Session-Sender test packet and the Session-
Reflector R1 returns the test packet. The return test packet may be
transmitted back to the Session-Sender S1 on the same path (same set
of links and nodes) or a different path in the reverse direction from
the path taken towards the Session-Reflector R1.
The Session-Sender S1 and Session-Reflector R1 are connected via an
SR path [RFC8402]. The SR path can be an SR Policy
[I-D.ietf-spring-segment-routing-policy] on node S1 (called head-end)
with destination to node R1 (called tail-end).
T1 T2
/ \
+-------+ STAMP Test Packet +-------+
| | - - - - - - - - - - - | |
| S1 |======================|| R1 |
| |<- - - - - - - - - - - | |
+-------+ Return Test Packet +-------+
\
T4
Session-Sender Session-Reflector
(Timestamp,
Pop and Forward)
Figure 1: Loopback Mode Enabled with Network Programming Function
3. Overview
3.1. Enhanced Loopback Mode Enabled with Network Programming Function
As described in [I-D.ietf-spring-stamp-srpm], in loopback mode, the
STAMP Session-Sender S1 initiates Session-Sender test packets and the
Session-Reflector R1 forwards them back to the Session-Sender S1.
The received STAMP test packets are not punted out of the fast path
in forwarding at the Session-Reflector. At the Session-Reflector,
the loopback function simply makes the necessary changes to the
encapsulation including IP and UDP headers to return the STAMP test
packet to the Session-Sender S1. No STAMP test session is created on
the Session-Reflector R1. As described in
[I-D.ietf-spring-stamp-srpm], only round-trip delay can be measured
in the loopback mode. In SR networks, there is also a need to
measure one-way delay to provide low latency services.
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This document defines a new STAMP measurement mode, enhanced loopback
mode, that is loopback mode enabled with network programming
function. In this mode, both transmit (T1) and receive (T2)
timestamps in data plane are collected by the Session-Sender test
packets as shown in Figure 1. The network programming function
optimizes the "operations of punt test packet and generate return
test packet" on the Session-Reflector as timestamping is implemented
in forwarding fast path in hardware. This helps to achieve higher
STAMP test session scale and faster detection interval.
The Session-Sender adds transmit timestamp (T1) in the payload of the
Session-Sender test packet. The Session-Reflector adds the receive
timestamp (T2) in the payload of the received test packet in
forwarding fast path in hardware without punting the test packet
(e.g. to slow path or control-plane). The network programming
function enables Session-Reflector to add the receive timestamp (T2)
at a specific offset in the payload which is locally provisioned,
consistently in the network.
3.2. Example Provisioning Model
An example provisioning model and typical measurement parameters are
shown in Figure 2:
+------------+
| Controller |
+------------+
STAMP Mode / \ Timestamp Label/SRv6 EB
Enhanced Loopback Mode / \ Timestamp Offset
Timestamp Label/SRv6 EB / \ Timestamp Format
Timestamp Format / \
Missed Packet Count (N) / \
Delay Threshold/Count(TH/M) / \
Packet Loss Threshold(XofY) / \
v v
+-------+ +-------+
| | | |
| S1 |==========| R1 |
| | | |
+-------+ +-------+
Session-Sender Session-Reflector
Figure 2: Example Provisioning Model
Example of a STAMP mode is enhanced loopback mode defined in this
document. The values for Timestamp Label and SRv6 Endpoint Behaviour
may be provisioned as described in this document. Example of
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Timestamp Format is 64-bit PTPv2 [IEEE1588]. Example of Timestamp
Offset is 16 and 32 bytes for the unauthenticated and authenticated
STAMP Session-Sender test packets, respectively. Example of
threshold values configured for generating notifications are: Missed
Packet Count (N), Delay Exceeded Threshold and Packet Count (TH/M)
and Packet Loss Threshold (XofY), as described in this document.
The mechanisms to provision the Session-Sender and Session-Reflector
are outside the scope of this document.
4. Enhanced Performance Measurement Procedure
For enhanced performance monitoring of an end-to-end SR path
including SR Policy, STAMP Session-Sender test packets are
transmitted in loopback mode enabled with network programming
function to timestamp and forward the packet.
For SR Policy, the Session-Sender test packets are transmitted using
the Segment List (SL) of the Candidate-Path
[I-D.ietf-spring-segment-routing-policy]. When a Candidate-Path has
more than one Segment Lists, multiple Session-Sender test packets
MUST be transmitted, one using each Segment List.
4.1. Enhanced Performance Measurement Procedure for SR-MPLS Policies
An SR-MPLS Policy may contain a number of Segment Lists (SLs). A
Session-Sender test packet MUST be transmitted for each Segment List
of the SR-MPLS Policy. The content of an example Session-Sender test
packet for an end-to-end SR-MPLS Policy is shown in Figure 3.
The SR-MPLS header can contain the MPLS label stack of the forward
path or both forward and the reverse direction paths. In the former
case, the return test packets are received by the Session-Sender via
IP/UDP [RFC0768] return path and the MPLS header is removed by the
Session-Reflector.
In the latter case, the Segment List of the reverse direction SR path
is added in the Session-Sender test packet header to receive the
return test packet on a specific path, either using the Binding SID
[I-D.ietf-pce-binding-label-sid] or Segment List of the Reverse SR
Policy [I-D.ietf-pce-sr-bidir-path]. In this case, the MPLS header
is not removed by the Session-Reflector.
In both cases, the Session-Sender MUST set the Destination Address
equal to the Session-Sender address in the IP header of the test
packets.
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In this document, two new Timestamp Labels are defined for SR-MPLS
data plane to enable network programming function for "timestamp, pop
and forward" the received test packet, one for unauthenticated mode
and one for authenticated mode.
In the Session-Sender test packets for SR-MPLS Policies, a Timestamp
Label is added in the MPLS header as shown in Figure 3, to collect
"Receive Timestamp" field in the payload of the test packet. The
Label Stack for the reverse direction SR-MPLS path can be added after
the Timestamp Label (not shown in the Figure) to receive the return
test packet on a specific path. When a Session-Reflector receives a
packet with Timestamp Label, after timestamping the packet at a
specific offset, the Session-Reflector pops the Timestamp Label and
forwards the packet using the next label or IP header in the packet
(just like the data packets for the normal traffic).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label(1) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label(n) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extension Label (15) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp Label (TBA1 or TBA2) | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Header |
. Source IP Address = Session-Sender IPv4 or IPv6 Address .
. Destination IP Address = Session-Sender IPv4 or IPv6 Address .
. Protocol = UDP .
. .
+---------------------------------------------------------------+
| UDP Header |
. Source Port = As chosen by Session-Sender .
. Destination Port = As chosen by Session-Sender .
. .
+---------------------------------------------------------------+
| Payload = Test Packet as specified in Section 3 of RFC 8972 |
. in Figure 1 and Figure 3 .
. .
+---------------------------------------------------------------+
Figure 3: Example STAMP Test Packet with Timestamp Label for SR-MPLS
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4.1.1. Timestamp Label Allocation
The timestamp Labels for STAMP test packets in unauthenticated and
authenticated modes can be allocated using one of the following
methods:
* Labels (values TBA1 and TBA2) assigned by IANA from the "Extended
Special-Purpose MPLS Values" [RFC9017]. For Label (value TBA1),
the timestamp offset is fixed at byte-offset 16 from the start of
the payload for the STAMP test packets in unauthenticated mode,
and Label (value TBA2) at byte-offset 32 from the start of the
payload for the STAMP test packets in authenticated mode, both
using the timestamp format 64-bit PTPv2.
* Labels allocated by a Controller from the global table of the
Session-Reflector. The Controller provisions the labels on both
Session-Sender and Session-Reflector, as well as timestamp offsets
and timestamp formats.
* Labels allocated by the Session-Reflector. The signaling and IGP
flooding extension for the labels (including their timestamp
offsets and timestamp formats) are outside the scope of this
document.
4.1.2. Node Capability for Timestamp Label
The STAMP Session-Sender needs to know if the Session-Reflector can
process the Timestamp Label to avoid dropping test packets. The
signaling extension or local configuration for this capability
exchange is outside the scope of this document.
4.2. Enhanced Performance Measurement Procedure for SRv6 Policies
An SRv6 Policy may contain a number of Segment Lists. Each Segment
List may contain a number of SRv6 SIDs as defined in [RFC8986],
[I-D.filsfils-spring-net-pgm-extension-srv6-usid] and
[I-D.ietf-spring-srv6-srh-compression]. A Session-Sender test packet
MUST be transmitted for each Segment List of the SRv6 Policy. An
SRv6 Policy may contain an SRv6 Segment Routing Header (SRH) carrying
a Segment List as described in [RFC8754]. The content of an example
Session-Sender test packet for an end-to-end SRv6 Policy using an SRH
is shown in Figure 4.
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The SRH can contain the Segment List of the forward path only or both
forward and the reverse direction paths. In the former case, an
inner IPv6 header (after the SRH and before the UDP header) MUST be
added that contains the Destination Address equal to the Session-
Sender address as shown in Figure 4. In this case, the SRH is
removed by the Session-Reflector and IP/UDP return path is used.
In the latter case, the Segment List of the reverse direction SR path
is added in the SRH to receive the return test packet on a specific
path, either using the Binding SID [I-D.ietf-pce-binding-label-sid]
or Segment List of the Reverse SR Policy
[I-D.ietf-pce-sr-bidir-path]. In this case, the SRH is not removed
by the Session-Reflector and an inner IPv6 header is not required.
When the return test packet contains an SRH at the Session-Sender,
the procedure defined for upper-layer header processing for SRv6 SIDs
in [RFC8986] MUST be used to process the UDP header after the SRH in
the received test packets.
The [RFC8986] defines SRv6 Endpoint Behaviours (EB) for SRv6 nodes.
In this document, two new Timestamp Endpoint Behaviours are defined
for Segment Routing Header (SRH) [RFC8754] to enable "Timestamp and
Forward (TSF)" function for the received test packets, one for
unauthenticated mode and one for authenticated mode.
In the Session-Sender test packets for SRv6 Policies, Timestamp
Endpoint Function (End.TSF) is carried with the target Segment
Identifier (SID) in SRH [RFC8754] as shown in Figure 4, to collect
"Receive Timestamp" field in the payload of the test packet. The
Segment List for the reverse direction path can be added after the
target SID to receive the return test packet on a specific path.
When a Session-Reflector receives a packet with Timestamp Endpoint
(End.TSF) for the target SID which is local, after timestamping the
packet at a specific offset, the Session-Reflector forwards the
packet using the next SID in the SRH or inner IPv6 header in the
packet (just like the data packets for the normal traffic).
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+---------------------------------------------------------------+
| IP Header |
. Source IP Address = Session-Sender IPv6 Address .
. Destination IP Address = Destination IPv6 Address .
. Next-Header = 43 (Type SRH) .
. .
+---------------------------------------------------------------+
| SRH as specified in RFC 8754 |
. <Segment List> .
. SRv6 Endpoint End.TSF (value TBA3 or TBA4) .
. .
+---------------------------------------------------------------+
| IP Header |
. Source IP Address = Session-Sender IPv6 Address .
. Destination IP Address = Session-Sender IPv6 Address .
. Next-Header = UDP (17) .
. .
+---------------------------------------------------------------+
| UDP Header |
. Source Port = As chosen by Session-Sender .
. Destination Port = As chosen by Session-Sender .
. .
+---------------------------------------------------------------+
| Payload = Test Packet as specified in Section 3 of RFC 8972 |
. in Figure 1 and Figure 3 .
. .
+---------------------------------------------------------------+
Figure 4: Example STAMP Test Packet with Endpoint Function for SRv6
4.2.1. Timestamp Endpoint Function Assignment
The Timestamp Endpoint Functions for "Timestamp and Forward" can be
signaled using one of the following methods:
* Timestamp Endpoint Functions (values TBA3 and TBA4) assigned by
IANA from the "SRv6 Endpoint Behaviors Registry". For endpoint
behaviour (value TBA3), the timestamp offset is fixed at byte-
offset 16 from the start of the payload for the STAMP test packets
in unauthenticated mode, and endpoint behaviour (value TBA4) at
byte-offset 32 from the start of the payload for the STAMP test
packets in authenticated mode, both using the timestamp format
64-bit PTPv2.
* Timestamp Endpoint Functions assigned by a Controller. The
Controller provisions the values on both Session-Sender and
Session-Reflector, as well as timestamp offsets and timestamp
formats.
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* Timestamp Endpoint Functions assigned by the Session-Reflector.
The signaling and IGP flooding extension for the endpoint
functions (including timestamp offsets and timestamp formats) are
outside the scope of this document.
4.2.2. Node Capability for Timestamp Endpoint Function
The STAMP Session-Sender needs to know if the Session-Reflector can
process the Timestamp Endpoint Function to avoid dropping test
packets. The signaling extension for this capability exchange is
outside the scope of this document.
5. Example Failure Notifications
The timestamps T1 and T2 are used to measure the one-way delay. The
delay metrics for an end-to-end SR path are notified, for example,
when consecutive M number of test packets have measured delay values
exceed the user-configured threshold TH, where M (Delay Exceeded
Packet Count) and TH (Absolute and Percentage Delay Exceeded
Thresholds) are also locally provisioned values.
The round-trip packet loss for an end-to-end SR path is calculated
using the Sequence Number in the Session-Sender test packets. The
packet loss metric is notified when X number of Session-Sender test
packets were lost out of last Y number of test packets transmitted by
the Session-Sender, where Threshold XofY is locally provisioned
value.
STAMP session state as UP (i.e. Connectivity verification success)
for an end-to-end SR path is initially notified as soon as one or
more return test packets are received at the Session-Sender.
STAMP session state as DOWN (i.e. Connectivity verification failure)
for an end-to-end SR path is notified when consecutive N number of
return test packets are not received at the Session-Sender, where N
(Missed Packet Count) is a locally provisioned value.
In the loopback mode, a connectivity verification failure on the
reverse direction path can cause the return test packets to not reach
the Session-Sender. This is also true in the case where the return
test packets are generated by the stateless Session-Reflector in two-
way measurement. The stateful Session-Reflector can solve this issue
by maintaining the forwarding direction state and notifying a
connectivity verification success and failure to the Session-Sender.
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6. Security Considerations
The STAMP protocol is intended for deployment in limited domains
[RFC8799]. As such, it assumes that a node involved in the STAMP
protocol operation has previously verified the integrity of the path
and the identity of the far-end Session-Reflector.
The security considerations specified in [RFC8762] and [RFC8972] also
apply to the procedures defined in this document. Specifically, the
message integrity protection using HMAC, as defined in Section 4.4 of
[RFC8762] also apply to the procedure described in this document.
7. IANA Considerations
IANA maintains the "Special-Purpose Multiprotocol Label Switching
(MPLS) Label Values" registry (see <https://www.iana.org/assignments/
mpls-label-values/mpls-label-values.xml>). IANA is requested to
allocate Timestamp Label value from the "Extended Special-Purpose
MPLS Label Values" registry:
+-------------+---------------------------------+---------------+
| Value | Description | Reference |
+-------------+---------------------------------+---------------+
| TBA1 | Timestamp Label | This document |
| | for offset 16 for STAMP | |
| | in Unauthenticated Mode | |
+-------------+---------------------------------+---------------+
| TBA2 | Timestamp Label | This document |
| | for offset 32 for STAMP | |
| | in Authenticated Mode | |
+-------------+---------------------------------+---------------+
IANA is requested to allocate, within the "SRv6 Endpoint Behaviors
Registry" sub-registry belonging to the top-level "Segment Routing
Parameters" registry [RFC8986], the following allocation:
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+-------------+---------------------------------+---------------+
| Value | Endpoint Behavior | Reference |
+-------------+---------------------------------+---------------+
| TBA3 | End.TSF (Timestamp and Forward) | This document |
| | for offset 16 for STAMP | |
| | in Unauthenticated Mode | |
+-------------+---------------------------------+---------------+
| TBA4 | End.TSF (Timestamp and Forward) | This document |
| | for offset 32 for STAMP | |
| | in Authenticated Mode | |
+-------------+---------------------------------+---------------+
8. References
8.1. Normative References
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/info/rfc768>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple
Two-Way Active Measurement Protocol", RFC 8762,
DOI 10.17487/RFC8762, March 2020,
<https://www.rfc-editor.org/info/rfc8762>.
[RFC8972] Mirsky, G., Min, X., Nydell, H., Foote, R., Masputra, A.,
and E. Ruffini, "Simple Two-Way Active Measurement
Protocol Optional Extensions", RFC 8972,
DOI 10.17487/RFC8972, January 2021,
<https://www.rfc-editor.org/info/rfc8972>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>.
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[I-D.ietf-spring-stamp-srpm]
Gandhi, R., Filsfils, C., Voyer, D., Chen, M., Janssens,
B., and R. Foote, "Performance Measurement Using Simple
TWAMP (STAMP) for Segment Routing Networks", Work in
Progress, Internet-Draft, draft-ietf-spring-stamp-srpm-03,
1 February 2022, <https://www.ietf.org/archive/id/draft-
ietf-spring-stamp-srpm-03.txt>.
8.2. Informative References
[IEEE1588] IEEE, "1588-2008 IEEE Standard for a Precision Clock
Synchronization Protocol for Networked Measurement and
Control Systems", March 2008.
[RFC7880] Pignataro, C., Ward, D., Akiya, N., Bhatia, M., and S.
Pallagatti, "Seamless Bidirectional Forwarding Detection
(S-BFD)", RFC 7880, DOI 10.17487/RFC7880, July 2016,
<https://www.rfc-editor.org/info/rfc7880>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>.
[RFC8799] Carpenter, B. and B. Liu, "Limited Domains and Internet
Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
<https://www.rfc-editor.org/info/rfc8799>.
[RFC9017] Andersson, L., Kompella, K., and A. Farrel, "Special-
Purpose Label Terminology", RFC 9017,
DOI 10.17487/RFC9017, April 2021,
<https://www.rfc-editor.org/info/rfc9017>.
[I-D.ietf-spring-srv6-srh-compression]
Cheng, W., Filsfils, C., Li, Z., Decraene, B., Cai, D.,
Voyer, D., Clad, F., Zadok, S., Guichard, J. N., Aihua,
L., Raszuk, R., and C. Li, "Compressed SRv6 Segment List
Encoding in SRH", Work in Progress, Internet-Draft, draft-
ietf-spring-srv6-srh-compression-00, 11 February 2022,
<https://www.ietf.org/archive/id/draft-ietf-spring-srv6-
srh-compression-00.txt>.
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[I-D.filsfils-spring-net-pgm-extension-srv6-usid]
Filsfils, C., Garvia, P. C., Cai, D., Voyer, D., Meilik,
I., Patel, K., Henderickx, W., Jonnalagadda, P., Melman,
D., Liu, Y., and J. Guichard, "Network Programming
extension: SRv6 uSID instruction", Work in Progress,
Internet-Draft, draft-filsfils-spring-net-pgm-extension-
srv6-usid-12, 13 December 2021,
<https://www.ietf.org/archive/id/draft-filsfils-spring-
net-pgm-extension-srv6-usid-12.txt>.
[I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
P. Mattes, "Segment Routing Policy Architecture", Work in
Progress, Internet-Draft, draft-ietf-spring-segment-
routing-policy-16, 28 January 2022,
<https://www.ietf.org/archive/id/draft-ietf-spring-
segment-routing-policy-16.txt>.
[I-D.ietf-pce-binding-label-sid]
Sivabalan, S., Filsfils, C., Tantsura, J., Previdi, S.,
and C. L. (editor), "Carrying Binding Label/Segment
Identifier in PCE-based Networks.", Work in Progress,
Internet-Draft, draft-ietf-pce-binding-label-sid-12, 24
January 2022, <https://www.ietf.org/archive/id/draft-ietf-
pce-binding-label-sid-12.txt>.
[I-D.ietf-pce-sr-bidir-path]
Li, C., Chen, M., Cheng, W., Gandhi, R., and Q. Xiong,
"Path Computation Element Communication Protocol (PCEP)
Extensions for Associated Bidirectional Segment Routing
(SR) Paths", Work in Progress, Internet-Draft, draft-ietf-
pce-sr-bidir-path-08, 9 September 2021,
<https://www.ietf.org/archive/id/draft-ietf-pce-sr-bidir-
path-08.txt>.
Acknowledgments
The authors would like to thank Greg Mirsky, Kireeti Kompella, and
Adrian Farrel for providing useful comments.
Authors' Addresses
Rakesh Gandhi (editor)
Cisco Systems, Inc.
Canada
Email: rgandhi@cisco.com
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Clarence Filsfils
Cisco Systems, Inc.
Email: cfilsfil@cisco.com
Navin Vaghamshi
Reliance
Email: Navin.Vaghamshi@ril.com
Moses Nagarajah
Telstra
Email: Moses.Nagarajah@team.telstra.com
Richard Foote
Nokia
Email: footer.foote@nokia.com
Mach(Guoyi) Chen
Huawei
Email: mach.chen@huawei.com
Amit Dhamija
Rakuten
Email: amit.dhamija@rakuten.com
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