SPRING WG W. Cheng
Internet-Draft L. Gong
Intended status: Standards Track China Mobile
Expires: January 12, 2022 Changwang. Lin
H3C Corporation
July 12, 2021
Encoding Network Slice Identification for SRv6
draft-cheng-spring-srv6-encoding-network-sliceid-00
Abstract
This document describe a method to encode network slicing identifier
within SRv6 domain.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Slice Identifier . . . . . . . . . . . . . . . . . . . . . . 2
3. SLID Assignment . . . . . . . . . . . . . . . . . . . . . . . 2
4. Per-Slice Forwarding . . . . . . . . . . . . . . . . . . . . 3
5. Backward Compatibility . . . . . . . . . . . . . . . . . . . 3
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
SRv6 Network Programming[RFC8986] enables the creation of overlays
with underlay optimization to be deployed in an SR domain[RFC8402].
As defined in [RFC8754], all inter-domain packets are encapsulated
for the part of the packet journey that is within the SR domain. The
outer IPv6 header [RFC8200] is originated by a node of the SR domain
and is destined to a node of the SR domain.
This document describes a novelty method to encode slice identifier
in the outer IPv6 header of an SR domain. Unlike other proposed
methods before, which will bring side effects on existed functions,
by encoding network slicing identifier in the source IPv6 address of
the outer header, this method avoids the drawbacks which previous
proposals incur.
1.1. 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 RFC 2119 [RFC2119].
2. Slice Identifier
Slice identifier (SLID) is a 16-bit Identifier which uniquely define
a slicing of the network in the specified SR domain.
3. SLID Assignment
When SR domain enables network slicing, the ingress PE should reserve
16 least significant bits in its locater for slicing use. When a
packet enters the SR domain from an ingress PE, the ingress PE
encapsulates the packet in an outer IPv6 header and optional SRH as
defined in [RFC8754]. The ingress PE MAY also classify the packet
into a slice and set the slice identifier as follows:
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o Set the SPI bit (SLID Presence Indicator) in the Traffic Class
field of the outer IPv6 header.
o Write this SLID in the 16 least significant bits of source address
of the outer IPv6 header.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| SPI Bit | Flow Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length | Next Header | Hop Limit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Source Address +
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | SLID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Destination Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The choice of the SPI bit from within the IPv6 Traffic Class field is
a domain-wide configuration and is outside the scope of this
document.
4. Per-Slice Forwarding
Any router within the SR domain that forwards a packet with SPI bit
set uses the SLID to select a slice and apply per-slice policies.
5. Backward Compatibility
PE routers that do not set the SPI bit do not enable the SLID
semantic of the IPv6 source address bits. Hence, SLID-aware routers
would not attempt to classify these packets into a slice.
Any router that does not process the SPI nor the SLID forwards
packets as usual.
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6. Acknowledgements
The authors would like to thank AAAA, BBBB and CCCC for their
insightful feedback on this document.
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>.
[RFC8986] Filsfils, C., Camarillo, P., 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>.
[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>.
7.2. Informative References
[RFC8200] Deering, S., and Hinden, D., "Internet Protocol, Version 6
(IPv6) Specification", RFC 8200, DOI 10.17487/RFC8200,
July 2017, <https://www.rfc-editor.org/info/rfc8200>.
Authors' Addresses
Weiqiang Cheng
China Mobile
Beijing
China
Email: chengweiqiang@chinamobile.com
Liyan Gong
China Mobile
Beijing
China
Email: gongliyan@chinamobile.com
Changwang Lin
H3C Corporation
Beijing
China
Email: linchangwang.04414@h3c.com
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