Internet DRAFT - draft-alston-spring-crh-bgp-signalling
draft-alston-spring-crh-bgp-signalling
SPRING Working Group A. Alston
Internet-Draft D. Henriques
Intended status: Standards Track Liquid Telecom
Expires: January 25, 2020 R. Bonica
Juniper Networks
July 24, 2019
BGP Extensions for IPv6 Compressed Routing Header (CRH)
draft-alston-spring-crh-bgp-signalling-01
Abstract
This document describes a new BGP extension for signalling the
mapping between Segment Identifiers (SID's), as used by a SRv6+
Compressed Routing Header (CRH) and the IPv6 Addresses they
represent. The extension defines both a new optional BGP attribute
to signal the Maximum SID Value (MSV) and a new Sub-Address Family
(SAFI) of the IPv6 Address family.
Status of This Memo
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This Internet-Draft will expire on January 25, 2020.
Copyright Notice
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include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License.
Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. SID Signalling . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. NLRI Format . . . . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4.1. Subsequent Address Family Identifiers (SAFI) Parameters . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Overview
The SRv6+ Compressed Routing Header uses an ordered sequence of
segment identifiers (SID) to specify the end to end path a packet
should follow through the network. This allows for much smaller
header sizes than found in the SRH (Segment Routing Header), which
utilizes an ordered sequence of 128 bit IPv6 address to achieve the
same goal. In addition, this method prevents the overloading of the
IPv6 address space.
This results in the need to signal the mapping between the SIDs used
in the CRH and the IPv6 addresses they represent. While such
signalling can be achieved through IGP extensions
[I-D.bonica-lsr-crh-isis-extensions] in a single network domain,
circumstances may dictate that the SID to address mapping be signaled
both to systems that do not partake in the IGP used within that
network domain, and between autonomous systems.
It is envisaged that such signalling will be required to signal,
among other things, deep packet inspection systems and flow analysis
systems that need the ability to see the full path a packet is
traversing, while at the same time not necessarily partaking in the
IGP which would normally be used for such signalling. This also
allows signalling of SID to Address mapping in environments that do
not run an IGP capable of such signalling.
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2. 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 BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. SID Signalling
3.1. NLRI Format
The format of the NLRI contained within the MP Reach Attribute is
comprised of a 16 bit Length (2 octets) field, followed by a series
of 20 octet tuples. The length of the first element of each tuple
MUST be 4 octets in length and represents the 32 bit SID. The second
element of the tuple is an IPv6 address and MUST be 16 octets in
length. The length of the NLRI can be calculated as (20)*N where N
is the number of tuples contained within the NLRI.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| NLRI Length |
| 2 octets |
+-+-+-+-+-+-+-+-+
| |
| SID 1 |
| (4 octets) |
| |
+-+-+-+-+-+-+-+-+
| |
| IPv6 Address 1|
| (16 octets) |
| |
+-+-+-+-+-+-+-+-+
| |
| SID N |
| (4 octets) |
| |
+-+-+-+-+-+-+-+-+
| |
| IPv6 Address N|
| (16 octets) |
| |
+-+-+-+-+-+-+-+-+
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4. IANA Considerations
This document defines new Sub-TLVs in the following existing
registry:
o Subsequent Address Family Identifiers (SAFI) Parameters
4.1. Subsequent Address Family Identifiers (SAFI) Parameters
A new SAFI in the IANA registry for "Subsequent Address Family
Identifiers (SAFI) Parameters" will be required:
Codepoint Description Reference
-----------------------------------------------
TBD SRv6+ CRH Signalling SAFI This document
5. Security Considerations
SRv6+ CRH BGP Signalling is envisioned to be run within a trusted
domain.
Further aspects of security are TBD.
6. Acknowledgements
The authors wish to acknowledge Ben Roberts for his support.
7. References
7.1. Normative References
[I-D.bonica-6man-comp-rtg-hdr]
Bonica, R., Kamite, Y., Niwa, T., Alston, A., Henriques,
D., So, N., Xu, F., Chen, G., Zhu, Y., Yang, G., and Y.
Zhou, "The IPv6 Compressed Routing Header (CRH)", draft-
bonica-6man-comp-rtg-hdr-05 (work in progress), July 2019.
[I-D.bonica-lsr-crh-isis-extensions]
Kaneriya, P., Shetty, R., Hegde, S., and R. Bonica, "IS-IS
Extensions To Support The IPv6 Compressed Routing Header
(CRH)", draft-bonica-lsr-crh-isis-extensions-00 (work in
progress), May 2019.
[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>.
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[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
DOI 10.17487/RFC4760, January 2007,
<https://www.rfc-editor.org/info/rfc4760>.
[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>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
7.2. Informative References
[I-D.ietf-6man-segment-routing-header]
Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment
Routing Header (SRH)", draft-ietf-6man-segment-routing-
header-21 (work in progress), June 2019.
[I-D.ietf-spring-segment-routing-mpls]
Bashandy, A., Filsfils, C., Previdi, S., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing with MPLS
data plane", draft-ietf-spring-segment-routing-mpls-22
(work in progress), May 2019.
[I-D.ietf-spring-srv6-network-programming]
Filsfils, C., Camarillo, P., Leddy, J.,
daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
Network Programming", draft-ietf-spring-srv6-network-
programming-01 (work in progress), July 2019.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>.
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Authors' Addresses
Andrew Alston
Liquid Telecom
Nairobi
Kenya
Email: Andrew.Alston@liquidtelecom.com
Daniam Henriques
Liquid Telecom
Johannesburg
South Africa
Email: daniam.henriques@liquidtelecom.com
Ron Bonica
Juniper Networks
Herndon, Virginia 20171
USA
Email: rbonica@juniper.net
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