Transparent Interconnection of Lots of Links (TRILL): Bidirectional Forwarding Detection (BFD) Support

Abstract

This document specifies use of the Bidirectional Forwarding Detection (BFD) protocol in Routing Bridge (RBridge) campuses based on the RBridge Channel extension to the Transparent Interconnection of Lots of Links (TRILL) protocol.

Transparent Interconnection of Lots of Links (TRILL): RBridge Channel Header Extension

“…Some RBridge Channel message payloads, such as BFD [RFC7175], provide their own security but where this is not true, consideration should be given, when specifying an RBridge Channel protocol, to recommending or requiring use of the security features of the RBridge Channel Header Extension.…”

“…The IETF TRILL base protocol [RFC6325] [RFC7780] has been extended with the RBridge Channel [RFC7178] facility to support transmission of typed messages (for example, Bidirectional Forwarding Detection (BFD) [RFC7175]) between two TRILL switches (RBridges) in the same campus and the transmission of such messages between RBridges and end stations on the same link. When sent between RBridges in the same campus, a TRILL Data packet with a TRILL Header is used, and the destination RBridge is indicated by nickname.…”

Transparent Interconnection of Lots of Links (TRILL) Use of IS-IS

“…This field is to support intelligent end stations that determine the egress IS (RBridge) for unicast data through a directory service or the like and that need a nickname for their first hop to insert as the ingress nickname to correctly format a TRILL Data frame (see [RFC6325], Section 4.6.2, point 8). It is also referenced in connection with the VLANs Appointed Sub-TLV (see Section 2.2.5) and can be used as the egress on one-hop RBridge Channel messages [RFC7178], for example, those use for BFD over TRILL [RFC7175]. o AF, AC, VM, BY, and TR: These flag bits have the following meanings when set to one, as specified in the listed section of [RFC6325]:…”

Transparent Interconnection of Lots of Links (TRILL): Adjacency

“…In such a BFD session, BFD is encapsulated as specified in [RFC7175]. The egress nickname to be used will have been learned from received Hellos.…”

“…See [RFC7175] for security considerations for BFD, whose use in connection with TRILL adjacency is discussed in this document, particularly Section 6. …”