http://www.rfc-editor.org/rfc/rfc6439.txt
RFC 6439: Routing Bridges (RBridges): Appointed Forwarders, R. Perlman, D. Eastlake, Y. Li, A. Banerjee, F. Hu2011-11-01T23:00:00-00:00TRILL supports multi-access LAN (Local Area Network) links that can have multiple end stations and RBridges attached. Where multiple RBridges are attached to a link, native traffic to and from end stations on that link is handled by a subset of those RBridges called "Appointed Forwarders", with the intent that native traffic in each VLAN (Virtual LAN) be handled by at most one RBridge. The purpose of this document is to improve the documentation of the Appointed Forwarder mechanism; thus, it updates RFC 6325. [STANDARDS-TRACK]