IGP Flexible Algorithm
draft-ietf-lsr-flex-algo-04
Network Working Group P. Psenak, Ed.
Internet-Draft Cisco Systems
Intended status: Standards Track S. Hegde
Expires: March 21, 2020 Juniper Networks, Inc.
C. Filsfils
K. Talaulikar
Cisco Systems, Inc.
A. Gulko
Thomson Reuters
September 18, 2019
IGP Flexible Algorithm
draft-ietf-lsr-flex-algo-04.txt
Abstract
IGP protocols traditionally compute best paths over the network based
on the IGP metric assigned to the links. Many network deployments
use RSVP-TE based or Segment Routing based Traffic Engineering to
enforce traffic over a path that is computed using different metrics
or constraints than the shortest IGP path. This document proposes a
solution that allows IGPs themselves to compute constraint based
paths over the network. This document also specifies a way of using
Segment Routing (SR) Prefix-SIDs and SRv6 locators to steer packets
along the constraint-based paths.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 21, 2020.
Psenak, et al. Expires March 21, 2020 [Page 1]
Internet-Draft IGP Flexible Algorithm September 2019
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements notation . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Flexible Algorithm . . . . . . . . . . . . . . . . . . . . . 5
5. Flexible Algorithm Definition Advertisement . . . . . . . . . 5
5.1. ISIS Flexible Algorithm Definition Sub-TLV . . . . . . . 5
5.2. OSPF Flexible Algorithm Definition TLV . . . . . . . . . 7
5.3. Common Handling of Flexible Algorithm Definition TLV . . 8
6. Sub-TLVs of ISIS FAD Sub-TLV . . . . . . . . . . . . . . . . 9
6.1. ISIS Flexible Algorithm Exclude Admin Group Sub-TLV . . . 9
6.2. ISIS Flexible Algorithm Include-Any Admin Group Sub-TLV . 10
6.3. ISIS Flexible Algorithm Include-All Admin Group Sub-TLV . 10
6.4. ISIS Flexible Algorithm Definition Flags Sub-TLV . . . . 11
7. Sub-TLVs of OSPF FAD TLV . . . . . . . . . . . . . . . . . . 12
7.1. OSPF Flexible Algorithm Exclude Admin Group Sub-TLV . . . 12
7.2. OSPF Flexible Algorithm Include-Any Admin Group Sub-TLV . 13
7.3. OSPF Flexible Algorithm Include-All Admin Group Sub-TLV . 13
7.4. OSPF Flexible Algorithm Definition Flags Sub-TLV . . . . 13
8. ISIS Flex-Algorithm Prefix Metric Sub-TLV . . . . . . . . . . 14
9. OSPF Flex-Algorithm Prefix Metric Sub-TLV . . . . . . . . . . 15
10. Advertisement of Node Participation in a Flex-Algorithm . . . 16
10.1. Advertisement of Node Participation for Segment Routing 16
10.2. Advertisement of Node Participation for Other
Applications . . . . . . . . . . . . . . . . . . . . . . 17
11. Advertisement of Link Attributes for Flex-Algorithm . . . . . 17
12. Calculation of Flexible Algorithm Paths . . . . . . . . . . . 18
12.1. Multi-area and Multi-domain Considerations . . . . . . . 19
13. Flex-Algorithm and Forwarding Plane . . . . . . . . . . . . . 20
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