We're noticing that when the SIP network gets congested, phones will
be fairly frantic about resending requests that they do not receive
(provisional or final) responses for.  Unfortunately, this only
increases the load on the proxy, which does not help the situation.
For INVITEs, the proxy sends 100 responses to stop the phone from
resending (and to keep it from failing over to another proxy).  But
for non-INVITE requests, 100 responses are SHOULD NOT.

However, we're considering adjusting the proxy so that if it receives
a resend of a non-INVITE request (on a non-reliable transport), it
will send a 100 response to (hopefully) quench the resends.

1) Will phones respond to 100 responses to non-INVITE requests to
   quench resends?

2) Will SIP agents behave badly if they receive 100 responses to
   non-INVITE requests?

Dale
_______________________________________________
Sip-implementors mailing list
Sip-implementors@cs.c...
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors