]> L3VPN Address Prefix Based Outbound Route Filter for BGP-4 Huawei
xuxiaohu@huawei.com
This document defines a new Outbound Router Filter (ORF) type for BGP, refered to as "L3VPN Address Prefix Outbound Route Filter", that can be used to perform L3VPN 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 L3VPN address families. The L3VPN Address Prefix ORF is applicable in the Virtual Subnet context.
The Outbound Route Filtering (ORF) Capability defined in 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 is used to perform address-prefix-based route filtering. However, the Address Prefix ORF is not much suitable for L3VPN route filting since there is no Route-Target (RT) field contained in the Address Prefix ORF entry. This document builds on and defines a new ORF-type for BGP, refered to as "L3VPN Address Prefix Outbound Route Filter (L3VPN Address Prefix ORF)", that can be used to perform L3VPN address-prefix-based route filtering. The L3VPN 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 L3VPN address families. The L3VPN Address Prefix ORF is applicable to reduce the RIB size of PE routers in the Virtual Subnet context.
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.
This memo makes use of the terms defined in and .
The ORF-Type for the L3VPN Address Prefix ORF-Type is TBD. A L3VPN 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, a L3VPN Address Prefix ORF entry consists of the following fields <Sequence, Action, Match, Reserved, Route-Target, Minlen, Maxlen, Length, Prefix>. Note that the Prefix field here doesn't include the Route Distinguisher (RD) part of a L3VPN address prefix. For example, in the case of a VPNv4 address prefix, only the IPv4 address prefix part of that VPNv4 address prefix is contained in that Prefix field. A L3VPN Address Prefix ORF entry is encoded as follows: the "Action", "Match" and "Reserved" fields of the entry are encoded in the common part , while the remaining fields of the entry are encoded in the "type specific part" , as shown in Figure 1. When the Action component of an ORF entry specifies REMOVE-ALL, the entry consists of only the common part.
When performing route matching search on those L3VPN routes which are assocaited with the Route Target as specified in the received L3VPN Adress Prefix ORF entries, the Address-Prefix-ORF-specific matching rules as defined in are almost preserved except that the RD SHOULD be ingored.
The authors would like to thank Mach Chen and Shunwan Zhuang for their comments on this document.
The ORF-type for the L3VPN Address Prefix ORF needs to be assigned by the IANA.
This document does not introduce any new security considerations.
&RFC2119;