[SIPForum-discussion] Require 100rel in 18x Response

[Klier, Heino]

Hi all,

I am struggeling with some 100rel issues. The message flow is as follows:

Bob -------- INVITE (SDP1)Support: 100rel ------> Alice 
Bob <-------  181   ------- Alice
Bob <-------  183   ------- Alice
Bob <-------  183 (SDP2) Require: 100rel  <------ Alice
Bob does NOT answer with a PRACK and as part of this the call fails.


Only in the third provisional response there is a Require 100rel header, but Bob doesn't answer with a PRACK Message.
I do not find any information in RFC's if this behaviour is allowed and which UA is doing wrong in 100rel handling (Bob or Alice).

Could anybody please give some advice?

Thanks and Regards
Heino