http://www.rfc-editor.org/rfc/rfc6327.txt
RFC 6327: Routing Bridges (RBridges): Adjacency, D. Eastlake 3rd, R. Perlman, A. Ghanwani, D. Dutt, V. Manral2011-07-01T23:00:00-00:00TRILL supports multi-access LAN (Local Area Network) links that can have multiple end stations and RBridges attached. This document describes four aspects of the TRILL LAN Hello protocol used on such links, particularly adjacency, designated RBridge selection, and MTU (Maximum Transmission Unit) and pseudonode procedures, with state machines. There is no change for IS-IS point-to-point Hellos used on links configured as point-to-point in TRILL. [STANDARDS-TRACK]