This document specifies the Intermediate System to Intermediate System (IS-IS) extensions necessary to support link state routing for any protocols running directly over Layer-2. While supporting this concept involves several pieces@ this document only describes extensions to IS-IS. Furthermore@ the Type@ Length@ Value pairs (TLVs) described in this document are generic Layer-2 additions@ and specific ones as needed are defined in the IS-IS technology-specific extensions. We leave it to the systems using these IS-IS extensions to explain how the information carried in IS-IS is used.