draft-ietf-lsr-ip-flexalgo-00.txt   draft-ietf-lsr-ip-flexalgo-01.txt 
LSR Working Group W. Britto LSR Working Group W. Britto
Internet-Draft S. Hegde Internet-Draft S. Hegde
Intended status: Standards Track P. Kaneriya Intended status: Standards Track P. Kaneriya
Expires: June 26, 2021 R. Shetty Expires: October 29, 2021 R. Shetty
R. Bonica R. Bonica
Juniper Networks Juniper Networks
P. Psenak P. Psenak
Cisco Systems Cisco Systems
December 23, 2020 April 27, 2021
IGP Flexible Algorithms (Flex-Algorithm) In IP Networks IGP Flexible Algorithms (Flex-Algorithm) In IP Networks
draft-ietf-lsr-ip-flexalgo-00 draft-ietf-lsr-ip-flexalgo-01
Abstract Abstract
An IGP Flexible Algorithm (Flex-Algorithm) allows IGP to compute An IGP Flexible Algorithm (Flex-Algorithm) allows IGP to compute
constraint-based paths. As currently defined, IGP Flex-Algorithm is constraint-based paths. As currently defined, IGP Flex-Algorithm is
used with Segment Routing (SR) data planes - SR MPLS and SRv6. used with Segment Routing (SR) data planes - SR MPLS and SRv6.
Therefore, Flex-Algorithm cannot be deployed in the absence of SR. Therefore, Flex-Algorithm cannot be deployed in the absence of SR.
This document extends IGP Flex-Algorithm, so that it can be used for This document extends IGP Flex-Algorithm, so that it can be used for
regular IPv4 and IPv6 prefixes. This allows Flex-Algorithm to be regular IPv4 and IPv6 prefixes. This allows Flex-Algorithm to be
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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 June 26, 2021. This Internet-Draft will expire on October 29, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2021 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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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Algorithm 1 | Algorithm 2 | Algorithm ... | Algorithm n | | Algorithm 1 | Algorithm 2 | Algorithm ... | Algorithm n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: ISIS IP Algorithm Sub-TLV Figure 1: ISIS IP Algorithm Sub-TLV
o Type: IP Algorithm Sub-TLV (Value TBD by IANA) o Type: IP Algorithm Sub-TLV (Value 29)
o Length: Variable o Length: Variable
o Algorithm (1 octet): value from 1 to 255. o Algorithm (1 octet): value from 1 to 255.
The IP Algorithm Sub-TLV MUST be propagated throughout the level and The IP Algorithm Sub-TLV MUST be propagated throughout the level and
MUST NOT be advertised across level boundaries. Therefore, the S bit MUST NOT be advertised across level boundaries. Therefore, the S bit
in the Router Capability TLV, in which the IP Algorithm Sub-TLV is in the Router Capability TLV, in which the IP Algorithm Sub-TLV is
advertised, MUST NOT be set. advertised, MUST NOT be set.
skipping to change at page 7, line 13 skipping to change at page 7, line 13
format: format:
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 | Length |R|R|R|R| MTID | | Type | Length |R|R|R|R| MTID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ISIS IPv4 Algorithm Prefix Reachability TLV ISIS IPv4 Algorithm Prefix Reachability TLV
o Type: IPv4 Algorithm Prefix Reachability TLV (Value TBD by IANA). o Type: IPv4 Algorithm Prefix Reachability TLV (Value 126).
o Length: variable. o Length: variable.
o R bits (4 bits): reserved for future use. They MUST be set to o R bits (4 bits): reserved for future use. They MUST be set to
zero on transmission and MUST be ignored on receipt. zero on transmission and MUST be ignored on receipt.
o MTID (12 bits): Multitopology Identifier as defined in [RFC5120]. o MTID (12 bits): Multitopology Identifier as defined in [RFC5120].
Note that the value 0 is legal. Note that the value 0 is legal.
Followed by one or more prefix entries of the form: Followed by one or more prefix entries of the form:
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In cases where a prefix advertisement is received in both a IPv4 In cases where a prefix advertisement is received in both a IPv4
Prefix Reachability TLV and an IPv4 Algorithm Prefix Reachability Prefix Reachability TLV and an IPv4 Algorithm Prefix Reachability
TLV, the IPv4 Prefix Reachability advertisement MUST be preferred TLV, the IPv4 Prefix Reachability advertisement MUST be preferred
when installing entries in the forwarding plane. when installing entries in the forwarding plane.
6.2. The ISIS IPv6 Algorithm Prefix Reachability TLV 6.2. The ISIS IPv6 Algorithm Prefix Reachability TLV
The ISIS IPv6 Algorithm Prefix Reachability TLV is identical to the The ISIS IPv6 Algorithm Prefix Reachability TLV is identical to the
ISIS IPv4 Algorithm Prefix Reachability TLV, except that it has a ISIS IPv4 Algorithm Prefix Reachability TLV, except that it has a
unique type. The type is TBD by IANA. unique type. The type is 127.
A router receiving multiple IPv6 Algorithm Prefix Reachability A router receiving multiple IPv6 Algorithm Prefix Reachability
advertisements for the same prefix, from the same originator, each advertisements for the same prefix, from the same originator, each
with a different Algorithm, MUST select the first advertisement in with a different Algorithm, MUST select the first advertisement in
the lowest-numbered LSP and ignore any subsequent IPv6 Algorithm the lowest-numbered LSP and ignore any subsequent IPv6 Algorithm
Prefix Reachability advertisements for the same prefix for any other Prefix Reachability advertisements for the same prefix for any other
Algorithm. Algorithm.
A router receiving multiple IPv6 Algorithm Prefix Reachability A router receiving multiple IPv6 Algorithm Prefix Reachability
advertisements for the same prefix, from different originators, each advertisements for the same prefix, from different originators, each
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+-------+------------------+---------------------------+ +-------+------------------+---------------------------+
| TBD | IP Algorithm TLV | This Document Section 5.2 | | TBD | IP Algorithm TLV | This Document Section 5.2 |
+-------+------------------+---------------------------+ +-------+------------------+---------------------------+
This document also updates the "Sub-TLVs for TLV 242" registry as This document also updates the "Sub-TLVs for TLV 242" registry as
follows: follows:
+-------+----------------------+---------------------------+ +-------+----------------------+---------------------------+
| Value | TLV Name | Reference | | Value | TLV Name | Reference |
+-------+----------------------+---------------------------+ +-------+----------------------+---------------------------+
| TBD | IP Algorithm Sub-TLV | This Document Section 5.1 | | 29 | IP Algorithm Sub-TLV | This Document Section 5.1 |
+-------+----------------------+---------------------------+ +-------+----------------------+---------------------------+
This document also updates the "ISIS TLV Codepoints Registry" This document also updates the "ISIS TLV Codepoints Registry"
registry as follows: registry as follows:
+-------+----------------------------------+------------------------+ +-------+----------------------------------+------------------------+
| Value | TLV Name | Reference | | Value | TLV Name | Reference |
+-------+----------------------------------+------------------------+ +-------+----------------------------------+------------------------+
| TBD | IPv4 Algorithm Prefix | This document, | | 126 | IPv4 Algorithm Prefix | This document, |
| | Reachability TLV | Section 6.1 | | | Reachability TLV | Section 6.1 |
| TBD | IPv6 Algorithm Prefix | This document, | | 127 | IPv6 Algorithm Prefix | This document, |
| | Reachability TLV | Section 6.2 | | | Reachability TLV | Section 6.2 |
| TBD |
+-------+----------------------------------+------------------------+ +-------+----------------------------------+------------------------+
This document updates the "OSPFv2 Extended Prefix Opaque LSA TLVs" This document updates the "OSPFv2 Extended Prefix Opaque LSA TLVs"
registry as follows:: registry as follows::
+-------+----------------------------------+------------------------+ +-------+----------------------------------+------------------------+
| Value | TLV Name | Reference | | Value | TLV Name | Reference |
+-------+----------------------------------+------------------------+ +-------+----------------------------------+------------------------+
| TBD | OSPFv2 Algorithm Prefix | This Document, | | TBD | OSPFv2 Algorithm Prefix | This Document, |
| | Reachability TLV | Section 6.1 | | | Reachability TLV | Section 6.1 |
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[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200, (IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017, DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>. <https://www.rfc-editor.org/info/rfc8200>.
14.2. Informative References 14.2. Informative References
[I-D.ietf-spring-srv6-network-programming] [I-D.ietf-spring-srv6-network-programming]
Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., Filsfils, C., Camarillo, P., Leddy, J., Voyer, D.,
Matsushima, S., and Z. Li, "SRv6 Network Programming", Matsushima, S., and Z. Li, "SRv6 Network Programming",
draft-ietf-spring-srv6-network-programming-27 (work in draft-ietf-spring-srv6-network-programming-28 (work in
progress), December 2020. progress), December 2020.
[IANA-ALG] [IANA-ALG]
IANA, "Sub-TLVs for TLV 242 (IS-IS Router CAPABILITY IANA, "Sub-TLVs for TLV 242 (IS-IS Router CAPABILITY
TLV)", August 1987, <https://www.iana.org/assignments/igp- TLV)", August 1987, <https://www.iana.org/assignments/igp-
parameters/igp-parameters.xhtml#igp-algorithm-types>. parameters/igp-parameters.xhtml#igp-algorithm-types>.
[RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
IP Fast Reroute: Loop-Free Alternates", RFC 5286, IP Fast Reroute: Loop-Free Alternates", RFC 5286,
DOI 10.17487/RFC5286, September 2008, DOI 10.17487/RFC5286, September 2008,
 End of changes. 13 change blocks. 
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