Technical Summary
Link state routing protocols have hierarchical abstraction already
built into them. However, when lower levels are used for transit,
they must expose their internal topologies to each other, leading to
scale issues.
To avoid this, this document discusses extensions to the IS-IS
routing protocol that allow level 1 areas to provide transit, yet
only inject an abstraction of the level 1 topology into level 2.
Each level 1 area is represented as a single level 2 node, thereby
enabling greater scale.
Working Group Summary
Shepherd writeup indicates broad consensus and no controversy.
The WG agreed on experimental track for this document.
Document Quality
Shepherd writeup mentions one known shipping implementation.
Personnel
The Document Shepherd for this document is Christian Hopps. The
Responsible Area Director is John Scudder.