RFC 8668: Advertising Layer 2 Bundle Member Link Attributes in IS-IS

There are deployments where the Layer 3 interface on which IS-IS operates is a Layer 2 interface bundle. Existing IS-IS advertisements only support advertising link attributes of the Layer 3 interface. If entities external to IS-IS wish to control traffic flows on the individual physical links that comprise the Layer 2 interface bundle, link attribute information about the bundle members is required. This document introduces the ability for IS-IS to advertise the link attributes of Layer 2 (L2) Bundle Members.