MPLS Payload Protocol Identifier
draft-xu-mpls-payload-protocol-identifier-08
Network Working Group X. Xu
Internet-Draft Alibaba, Inc.
Intended status: Standards Track H. Assarpour
Expires: June 24, 2021 Broadcom
S. Ma
Mellanox
F. Clad
Cisco Systems, Inc.
December 21, 2020
MPLS Payload Protocol Identifier
draft-xu-mpls-payload-protocol-identifier-08
Abstract
The MPLS label stack has no explicit protocol identifier field to
indicate the protocol type of the MPLS payload. This document
proposes a mechanism for containing a protocol identifier field
within the MPLS packet, which is useful for any new encapsulation
header (e.g., INT metadata) which may need to be encapsulated with an
MPLS header.
Status of This Memo
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This Internet-Draft will expire on June 24, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Protocol Type Field . . . . . . . . . . . . . . . . . . . . . 3
4. Data Plane Processing of PIL . . . . . . . . . . . . . . . . 4
4.1. Egress LSRs . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. Ingress LSRs . . . . . . . . . . . . . . . . . . . . . . 4
4.3. Transit LSRs . . . . . . . . . . . . . . . . . . . . . . 5
4.4. Penultimate Hop LSRs . . . . . . . . . . . . . . . . . . 5
5. Signaling for PIL Processing Capability . . . . . . . . . . . 5
6. Alternative Approaches . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
9. Security Considerations . . . . . . . . . . . . . . . . . . . 6
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
10.1. Normative References . . . . . . . . . . . . . . . . . . 6
10.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
The MPLS label stack has no explicit protocol identifier field to
indicate the protocol type of the MPLS payload. This document
proposes a mechanism for containing a protocol identifier field
within the MPLS packet, which is useful for any new encapsulation
header (e.g., INT metadata) which may need to be encapsulated with an
MPLS header. With this explicit protocol identifier field, there is
no need any more for each new encapsulation header to deal with the
notorious first nibble issue associated with MPLS individually. More
specifically, there is no need to intentionally avoid the first
nibble of each new encapsulation header from being 0100 (IPv4) or
0110 (IPv6) and even worsely misuse the first nibble of each new
encapsulation header as an MPLS payload type field (e.g., MPLS-BIER
[RFC8296]). The tacit permission of misusing the first nibble of
each new encapsulation header as an MPLS payload type field would
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