2011/7/6 Olle E. Johansson oej@edvina.net:
Why? We are talking about the URI in the (Record-) Route header here, which _only_ indicates how to get to the next hop. If you put a SIPS URI in there, this has no consequence whatsoever for the complete path.
Because RFC 5630 says that if a Route header has SIPS the contact also has to be SIPS.
As mandated by [RFC3261], Section 12.1.1:
If the request that initiated the dialog contained a SIPS URI in the Request-URI or in the top Record-Route header field value, if there was any, or the Contact header field if there was no Record- Route header field, the Contact header field in the response MUST be a SIPS URI.
Thanks for pointing it out. I can imagine the reason for this requeriment: ensure that both parts of the communications (requests from both sides) use a secure layer.