1. Identifying intra-realm calls with explicit addressing realm identifier attribute François AUDET (audet@nortelnetworks.com) SIPPING WG Meeting IETF-57 draft-audet-sipping-add-realm-00.txt

2. 14 July 2003 draft-audet-sipping-add-realm-00.txt 2 Explicit addressing realm identifier Allows for explicitly adding a realm-id for private (i.e., “local”) addresses UAs can make decisions based on the presence of the realm-id Core idea is that if both media termination in a session have a-priory knowledge that they have have IP addresses in same addressing realm, they can use it

3. 14 July 2003 draft-audet-sipping-add-realm-00.txt 3 Explicit addressing realm identifier UA know that they have private adds in same realm only if they have the same realm-id If realm-id are different, use normal treatment (STUN, ICE, pray, etc.) If realm-id are same, use those addresses Need to configure realm-id only if multiple UA are behind same NAT Burden is on configuring the realm-id when needed Mechanism to configure outside of scope

4. 14 July 2003 draft-audet-sipping-add-realm-00.txt 4 Relationship to ICE Can be used with or without ICE Syntax based on ICE -00 Needs to be updated to ice-01 Allows for better migration to ICE Use realm-id to handle UAs that do not support ICE Optimize for not using ICE when we know we don’t need it

5. 14 July 2003 draft-audet-sipping-add-realm-00.txt 5 Format of realm identifier Has to be globally unique Could be a number, VPN identifier, something that looks like a domain name, etc. New attribute: includes an addressing-realm-type & addressing-realm-identifier Example in draft looks like a domain name Similar to phone-context in RFC2806-bis (tel URI) E.g.: a=addressing-realm:userdomain lab3.sanjose@foo.com