Network Working Group Z. Li
Internet-Draft China Mobile
Intended status: Standards Track T. Zhou
Expires: July 28, 2022 Huawei
J. Guo
ZTE Corp.
G. Mirsky
Ericsson
R. Gandhi
Cisco
January 24, 2022
Simple Two-Way Active Measurement Protocol Extensions for Performance
Measurement on LAG
draft-li-ippm-stamp-on-lag-01
Abstract
This document extends Simple Two-Way Active Measurement Protocol
(STAMP) to implement performance measurement on every member link of
a Link Aggregation Group (LAG). Knowing the measured metrics of each
member link of a LAG enables operators to enforce a performance based
traffic steering policy across the member links.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "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.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on July 28, 2022.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Micro Session on LAG . . . . . . . . . . . . . . . . . . . . 3
3. Member Link Validation . . . . . . . . . . . . . . . . . . . 4
3.1. LAG Member Link ID TLV . . . . . . . . . . . . . . . . . 4
3.2. Micro STAMP-Test Procedures . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Link Aggregation Group (LAG), as defined in [IEEE802.1AX], provides
mechanisms to combine multiple physical links into a single logical
link. This logical link offers higher bandwidth and better
resiliency, because if one of the physical member links fails, the
aggregate logical link can continue to forward traffic over the
remaining operational physical member links.
Usually, when forwarding traffic over LAG, the hash-based mechanism
is used to load balance the traffic across the LAG member links.
Link delay of each member link varies because of different transport
paths. To provide low latency service for time sensitive traffic, we
need to explicitly steer the traffic across the LAG member links
based on the link delay, loss and so on. That requires a solution to
measure the performance metrics of each member link of a LAG.
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Simple Two-Way Active Measurement Protocol (STAMP) [RFC8762] is an
active measurement method according to the classification given in
RFC7799 [RFC7799]. It provides a mechanism to measure both one-way
and round-trip performance metrics, like delay, delay variation, and
packet loss. Running a single STAMP test session over the
aggregation without the knowledge of each member link would make it
impossible to measure the performance of a given physical member
link. The measured metrics can only reflect the performance of one
member link or an average of some/all member links of the LAG.
This document extends STAMP to implement performance measurement on
every member link of a LAG. The proposed method could also
potentially apply to layer 3 ECMP (Equal Cost Multi-Path), e.g., with
SR-Policy [I-D.ietf-spring-segment-routing-policy].
2. Micro Session on LAG
This document intends to address the scenario (e.g., Figure 1) where
a LAG (e.g., the LAG includes three member links) directly connects
two nodes (A and B) . The goal is to measure the performance of each
link of the LAG.
+---+ +---+
| |-----------------------| |
| A |-----------------------| B |
| |-----------------------| |
| |-----------------------| |
+---+ +---+
Figure 1: PM for LAG
To measure the performance metrics of every member link of a LAG,
multiple sessions (one session for each member link) need to be
established between the two end points that are connected by the LAG.
These sessions are called micro sessions in the remainder of this
document.
All micro sessions of a LAG share the same Sender IP Address and
Receiver IP Address. As for the UDP Port, the micro sessions may
share the same Sender Port and Receiver Port pair, or each micro
session is configured with a different Sender Port and Receiver Port
pair. But from the operational point of view, the former is simpler
and is recommended.
At the Sender side, each micro STAMP session MUST be assgined with a
unique SSID [RFC8972]. Both the micro STAMP Session Sender and
Reflector MUST use SSID to correlate the Test packet to a micro
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session. If there is no such a session, or the SSID is not correct,
the Test packet MUST be discarded.
Test packets MAY carry the member link information for validation
check. For example, when a micro STAMP Session-Sender receives a
reflected Test packet, it may need to check whether the Test packet
is from the expected member link. The detailed description about the
member link validation is in section 3.
A micro STAMP Session-Sender MAY include the Follow-Up Telemetry TLV
[RFC8972] to request information from the micro Session-Reflector.
This timestamp might be important for the micro Session-Sender, as it
improves the accuracy of network delay measurement by minimizing the
impact of egress queuing delays on the measurement.
3. Member Link Validation
Test packets MAY carry the member link information for validation
check. The micro Session Sender can verify whether the test packet
is reveived from the expected member link. It can also verify
whether the packet is sent from the expected member link at the
Reflector side. The micro Session Reflector can verify whether the
test packet is received from the expected member link.
3.1. LAG Member Link ID TLV
STAMP TLV [RFC8972] mechanism extends STAMP Test packets with one or
more optional TLVs. This document defines the TLV Type (value TBA1)
for the LAG Member Link ID TLV that carries the micro STAMP Session-
Sender member link identifier and Session-Reflector member link
identifier. The format of the LAG Member Link ID TLV is shown as
follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags| Type = TBA1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sender Member Link ID | Reflector Member Link ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: LAG Member Link ID TLV
o Type: A one-octet field. Value TBA1 is allocated by IANA
(Section 5).
o Length: A two-octet field equal to the length of the Value field
in octets. The Length field value MUST be 4 octets.
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o Sender Member Link ID (2-octets in length): it is defined to carry
the LAG member link identifier of the Sender side. The value of
the Sender Member Link ID MUST be unique at the Session-Sender.
o Reflector Member Link ID (2-octets in length): it is defined to
carry the LAG member link identifier of the Reflector side. The
value of the Reflector Member ID MUST be unique at the Session-
Reflector.
3.2. Micro STAMP-Test Procedures
The micro STAMP-Test reuses the procedures as defined in Section 4 of
STAMP [RFC8762] with the following additions.
The micro STAMP Session-Sender MUST send the micro STAMP-Test packets
over the member link with which the session is associated. The
configuration and management of the mapping between a micro STAMP
session and the Sender/Reflector member link identifiers are outside
the scope of this document.
When sending a Test packet, the micro STAMP Session-Sender MUST set
the Sender Member Link ID field with the member link identifier
associated with the micro STAMP session. If the Session-Sender knows
the Reflector member link identifier, the Reflector Member Link ID
field MUST be set. Otherwise, the Reflector Member Link ID field
MUST be zero. The Reflector member link identifier can be obtained
from pre-configuration or learned through data plane (e.g., learned
from a reflected Test packet). How to obtain/learn the Reflector
member link identifier is outside of this document's scope.
When the micro STAMP Session-Reflector receives a Test packet, if the
Reflector Member Link ID is not zero, the micro STAMP Session-
Reflector MUST use the Reflector member link identifier to check
whether it is associated with the micro STAMP session. If the
validation fails, the Test packet MUST be discarded. If all
validations passed, the Session-Reflector sends a reflected Test
packet to the Session-Sender. The micro STAMP Session-Reflector MUST
put the Sender and Reflector member link identifiers that are
associated with the micro STAMP session in the Sender Member Link ID
and Reflector Member Link ID fields respectively. The Sender member
link identifier is copied from the received Test packet.
When receiving a reflected Test packet, the micro Session-Sender MUST
use the Sender Member Link ID to validate whether the reflected Test
packet is correctly transmitted over the expected member link. If
the validation fails, the Test packet MUST be discarded. The micro
Session-Sender MUST use the Reflector Member Link ID to validate the
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Reflector's behavior. If the validation fails, the Test packet MUST
be discarded.
4. IANA Considerations
In the "STAMP TLV Types" registry created for [RFC8972], a new STAMP
TLV Type for LAG Member Link ID TLV is requested from IANA as
follows:
+----------------+-------------------+-----------------+------------+
| STAMP TLV Type | Description | Semantics | Reference |
| Value | | Definition | |
+----------------+-------------------+-----------------+------------+
| TBA1 | LAG Member Link | Section 3 | This |
| | ID TLV | | Document |
+----------------+-------------------+-----------------+------------+
New STAMP TLV Type
5. Security Considerations
The STAMP extension defined in this document is intended for
deployment in LAG scenario where Session-Sender and Session-Reflector
are directly connnected. As such, it's assumed that a node involved
in STAMP protocol operation has previously verified the integrity of
the LAG connection and the identity of its one-hop-away peer node.
This document does not introduce any additional security issues and
the security mechanisms defined in [RFC8762] and [RFC8972] apply in
this document.
6. Acknowledgements
The authors would like to thank Mach Chen, Min Xiao, Fang Xin for the
valuable comments to this work.
7. References
7.1. Normative References
[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>.
[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>.
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[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>.
7.2. Informative References
[I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
P. Mattes, "Segment Routing Policy Architecture", draft-
ietf-spring-segment-routing-policy-14 (work in progress),
October 2021.
[IEEE802.1AX]
IEEE Std. 802.1AX, "IEEE Standard for Local and
metropolitan area networks - Link Aggregation", November
2008.
Authors' Addresses
Zhenqiang Li
China Mobile
Email: li_zhenqiang@hotmail.com
Tianran Zhou
Huawei
China
Email: zhoutianran@huawei.com
Jun Guo
ZTE Corp.
China
Email: guo.jun2@zte.com.cn
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Greg Mirsky
Ericsson
United States of America
Email: gregimirsky@gmail.com
Rakesh Gandhi
Cisco
Canada
Email: rgandhi@cisco.com
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