BGP-LS Extensions for Advertising Path MTU
draft-zhu-idr-bgp-ls-path-mtu-04
Network Working Group Y. Zhu
Internet-Draft China Telecom
Intended status: Standards Track Z. Hu
Expires: February 11, 2021 S. Peng
Huawei Technologies
R. Mwehaire
MTN Uganda Ltd.
August 10, 2020
BGP-LS Extensions for Advertising Path MTU
draft-zhu-idr-bgp-ls-path-mtu-04
Abstract
BGP Link State (BGP-LS) describes a mechanism by which link-state and
TE information can be collected from networks and shared with
external components using the BGP routing protocol. The centralized
controller (PCE/SDN) completes the service path calculation based on
the information transmitted by the BGP-LS and delivers the result to
the Path Computation Client (PCC) through the PCEP or BGP protocol.
Segment Routing (SR) leverages the source routing paradigm, which can
be directly applied to the MPLS architecture with no change on the
forwarding plane and applied to the IPv6 architecture, with a new
type of routing header, called SRH. The SR uses the IGP protocol as
the control protocol. Compared to the MPLS tunneling technology, the
SR does not require additional signaling. Therefore, the SR does not
support the negotiation of the Path MTU. Since multiple labels or
SRv6 SIDs are pushed in the packets, it is more likely that the
packet size exceeds the path mtu of SR tunnel.
This document specifies the extensions to BGP Link State (BGP-LS) to
carry maximum transmission unit (MTU) messages of link. The PCE/SDN
calculates the Path MTU while completing the service path calculation
based on the information transmitted by the BGP-LS.
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].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Zhu, et al. Expires February 11, 2021 [Page 1]
Internet-Draft BGP-LS Extensions for Advertising Path MTU August 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Deploying scenarios . . . . . . . . . . . . . . . . . . . . . 5
4. BGP_LS Extensions for Link MTU . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
[RFC7752]describes the implementation mechanism of BGP-LS by which
link-state and TE information can be collected from networks and
shared with external components using the BGP routing protocol
[RFC4271]. BGP-LS allows the necessary Link-State Database (LSDB)
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