VPN Address Prefix Based Outbound Route Filter for BGP-4
draft-xu-idr-vpn-prefix-orf-00

Abstract

This document defines a new Outbound Router Filter (ORF) type for BGP, refered to as "VPN Address Prefix Outbound Route Filter", that can be used to perform VPN address-prefix-based route filtering. This ORF-type supports prefix-length- or range-based matching, wild-card-based address prefix matching, as well as the exact address prefix matching for VPN address families. The VPN Address Prefix ORF is applicable in the context of Virtual Subnet and may also be applicable in other BGP/MPLS VPN environments.

Status of This Memo

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Table of Contents

• 1. Introduction
• 1.1. Requirements Language
• 2. Terminology
• 3. VPN Address Prefix ORF Encoding
• 4. VPN Address Prefix ORF Matching
• 5. Acknowledgements
• 6. IANA Considerations
• 7. Security Considerations
• 8. References
• 8.1. Normative References
• 8.2. Informative References
• Author's Address

1. Introduction

The Outbound Route Filtering (ORF) Capability defined in [RFC5291] provides a mechanism for a BGP speaker to send to its BGP peer a set of ORFs that can be used by its peer to filter its outbound routing updates to the speaker. The Address Prefix ORF defined in [RFC5292] is used to perform address-prefix-based route filtering. However, the Address Prefix ORF is not much suitable for VPN route filting since there is no Route-Target (RT) field contained in the Address Prefix ORF entry.

This document builds on [RFC5292] and defines a new ORF-type for BGP, refered to as "VPN Address Prefix Outbound Route Filter (VPN Address Prefix ORF)", that can be used to perform VPN address-prefix-based route filtering. The VPN Address Prefix ORF supports prefix-length- or range-based matching, wild-card-based address prefix matching, as well as the exact address prefix matching for VPN address families. The VPN Address Prefix ORF is applicable in the context of Virtual Subnet [I-D.xu-l3vpn-virtual-subnet] and may also be applicable in other BGP/MPLS VPN environments.

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 [RFC5292] and [RFC4364].

3. VPN Address Prefix ORF Encoding

A VPN Address Prefix ORF entry includes a Route Target field in addition to those fields which have been contained in the Address Prefix ORF. That's to say, the VPN Address Prefix ORF entry consists of the fields <Sequence, Match, Route-Target, Length, Prefix, Minlen, Maxlen>. Note that the Prefix field here doesn't include the Route Distinguisher (RD) part of a VPN address prefix. For example, in the case of VPNv4 address prefix, only the IPv4 address prefix part is contained in that Prefix field.

4. VPN Address Prefix ORF Matching

When performing route matching search on those VPN routes which are assocaited with the Route Target as specified in the received VPN Adress Prefix ORF, the Address-Prefix-ORF-specific matching rules defined in [RFC5292] are almost preserved except that the RD SHOULD be ingored.

5. Acknowledgements

The authors would like to thank Mach Chen and Shunwan Zhuang for their comments on this document.

6. IANA Considerations

The type code of the VPN Address Prefix ORF needs to be assigned by the IANA.

7. Security Considerations

This document does not introduce any new security considerations.

8. References

8.1. Normative References

8.2. Informative References

Author's Address