Appendix A      SIP Compliance with RFC-2543 Information
SIP Responses
A-4
Cisco SIP IP Phone 7960 Administrator Guide
78-10497-02
1xx Response—Information Responses
2xx Response—Successful Responses
1xx Response Supported? Comments
100 Trying Yes The Cisco SIP IP phone generates this 
response for an incoming INVITE. Upon 
receiving this response, the phone waits 
for a 180 Ringing, 183 Session progress, 
or 200 OK response.
180 Ringing Yes None
181 Call is being 
forwarded
See comments
The Cisco SIP IP phone does not 
generate these responses, however, the 
phone does receive them. The phone 
processes these responses the same way 
that it processes the 100 Trying 
response.
182 Queued
183 Session 
Progress
The SIP IP phone does not generate this 
message. Upon receiving this response, 
the phone provides early media cut 
through and then waits for a 200 OK 
response.
2xx Response Supported? Comments
200 OK Yes None