Huawei Huawei Broadcom Cisco Intel Labs The IETF has standardized RBridges (Routing Bridges), devices that implement the TRILL (TRansparent Interconnection of Lots of Links) protocol, a standard for least cost transparent frame routing in multi-hop networks with arbitrary topologies, using link-state routing and encapsulation with a hop count. The TRILL base protocol standard supports up to 4K VLAN IDs (Virtual Local Area Network IDentifiers). However, there are applications that require more fine-grained labeling of data and end stations. This document updates RFC 6325 by specifying extensions to the TRILL protocol to accomplish this.