I bumped into this
problem the other day relating to sequencing of 180 Ringing and 183
Session Progress responses from UAS.
In the following
call flow (with either Cisco 7960 or Pingtel) User
Agent Client is ignoring 183 and thereby failing to provide early
media.
SIP
UAC
UAS
---INVITE---->
.... <----------------- 100 Trying
<--------------- 180 Ringing
<--------------- 183 Session Progress
However if we send , from UAS, 183 followed by and 180 responses , then UAC is providing early media.
Can someone tell me what should be the exact sequence of responses that RFC stipulates ?
Thanks,
Prakash
