Hi All, For today's discussion I have prepared two sequence diagrams to show the messaging flow for two scenarios: These attempt to build on the work by Tomohiro and Sebastien for the multiple network case. Sequence 1 - single NSI and NSA Sequence 2 - two NSAs each controlling local networks. Requestor agent has NSI interface to network A only. Guy ------------------------------------------------------------------------------------------------------------------ Guy Roberts, Ph.D Network Engineering & Planning DANTE - www.dante.net<http://www.dante.net/> Tel: +44 (0)1223 371 316 City House, 126-130 Hills Road Cambridge, CB2 1PQ, UK ------------------------------------------------------------------------------------------------------------------