Advertising Encapsulation Capability Using IS-IS
draft-xu-isis-encapsulation-cap-03

Abstract

In a particular network environment where MPLS-SPRING-enabled routers are partially deployed, it needs to transport MPLS traffic through an IP-based tunnel between two MPLS-SPRING-enabled routers so as to traverse non-MPLS routers. The ingress of the IP-based tunnel must know which encapsulation type is supported by the egress of that IP-based tunnel.This document describes how to advertise the encapsulation capability of MPLS-SPRING-enabled routers using IS-IS. Note that this encapsulation capablity advertisment may be applicalbe to other use cases as well.

Status of This Memo

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Copyright Notice

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Table of Contents

• 1. Introduction
• 1.1. Requirements Language
• 2. Terminology
• 3. Advertising Encapsulation Capability
• 4. Acknowledgements
• 5. IANA Considerations
• 6. Security Considerations
• 7. References
• 7.1. Normative References
• 7.2. Informative References
• Authors' Addresses

1. Introduction

[I-D.xu-spring-islands-connection-over-ip] describes a particular network environment where MPLS-SPRING-enabled routers are partially deployed and therefore it needs to transport MPLS traffic through an IP-based tunnel between two MPLS-SPRING-enabled routers so as to traverse non-MPLS routers. The ingress of the IP-based tunnel (i.e., tunnel encapsulator) must know which encapsulation type is supported by the egress of the IP-based tunnel (i.e., tunnel decapsulator).This document describes how to advertise the encapsulation capability of MPLS-SPRING-enabled routers using IS-IS. Note that this encapsulation capablity advertisment may be applicalbe to other use cases as well.

1.1. 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].

2. Terminology

This memo makes use of the terms defined in [RFC4971] and [I-D.xu-spring-islands-connection-over-ip].

3. Advertising Encapsulation Capability

MPLS-SPRING-enabled routers need to advertise the encapsulation type(s) they support by using a new sub-TLV of the IS-IS Router CAPABILITY TLV [RFC4971], referred to as Encapsulation Capability sub-TLV. The Encapsulation Capability sub-TLV could not appear more than once wihin a given IS-IS Router CAPABILITY TLV. The scope of the advertisement depends on the application but it is recommended that it SHOULD be domain-wide. The Type code of the Encapsualtion Cability sub-TLV is TBD, the Length value is vairalbe, and the Value field contains one or more Encapsulation Type sub-TLVs with each indicating a particular encapsulation format that the advertising router supports.

This document defines the following types of Encapsulation Type sub-TLV:

1. MPLS-in-IP tunnel [RFC4023] : Type code=TBD1; Length=0
2. MPLS-in-GRE tunnel [RFC4023]: Type code=TBD2; Length=0
3. MPLS-in-L2TPv3 tunnel [RFC4817]: Type code=TBD3; Length=0
4. MPLS-in-UDP tunnel [I-D.ietf-mpls-in-udp]: Type code=TBD4; Length=0
5. MPLS-in-IP tunnel with IPsec Transport Mode [RFC5566]: Type code=TBD5; Length=0

4. Acknowledgements

The authors would like to thank Carlos Pignataro for his valuable comments on this draft.

5. IANA Considerations

This memo includes a request to IANA for allocating the type codes for Encapsulation Capability sub-TLV and Encapsulation Type sub-TLVs.

6. Security Considerations

This document does not introduce any new security risk.

7. References

7.1. Normative References

7.2. Informative References

Authors' Addresses