http://www.rfc-editor.org/rfc/rfc4915.txt
RFC 4915: Multi-Topology (MT) Routing in OSPF, P. Psenak, S. Mirtorabi, A. Roy, L. Nguyen, P. Pillay-Esnault2007-06-01T23:00:00-00:00An optional extension to exclude selected links from the default topology is also described. [STANDARDS-TRACK]