RFC 3261 - Routing Changes

Introduced “loose routing” vs. RFC 3543’s “strict routing”
- Examples:
  - Pre-loaded (initial INVITE) Route header can be used instead of the default outbound proxy (DOP)
  - Pre-loaded Route header can be used to invoke “home proxy” services (when you are roaming)
  - Additional proxies can be added as needed (for example, adding routing during a call)
All elements must insert branch parameter as a transaction ID in Via header fields
Contact header required in all requests that establish a dialog
From and To tags are now mandatory
Recommend users of Fully Qualified Domain Name (FQDN) instead of IP addresses
Via loop detection no longer required of proxies

⇒ Use of Max-Forwards is now mandatory

Via hiding is deprecated (i.e., should no longer be used)

because it turned out not to be secure or useful

Slide Notes

J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, Sparks, M. Handley, and E. Schooler,”SIP: Session Initiation Protocol”, IETF, Network Working Group, RFC 3261, June 2002, Updated by RFC 3265, RFC 3853, RFC 4320, RFC 4916, RFC 5393, RFC 5621, RFC 5626, RFC 5630, RFC 5922, http://datatracker.ietf.org/doc/rfc3261/ Links to an external site.

Transcript

[slide167] Okay. We can also do source routing or loose source routing by purposely putting things in -- to force the packet to be routed along a particular path.