Appendix A      SIP Compliance with RFC-2543 Information
SIP Responses
A-8
Cisco SIP IP Phone 7960 Administrator Guide
78-10497-02
411 Length 
Required
See comments This response is only received by the 
phone in this release. 
This response indicates that the user 
refuses to accept the request without a 
defined content length. If received the 
phone resends the INVITE request if it 
can add a valid Content-Length header 
field.
413 Request Entity 
Too Large
See comments This response is only received by the 
phone in this release. 
If a retry after header field is contained 
in this response, then the user can 
attempt the call once again in the retry 
time provided.
414 
Request—URL 
Too Long
See comments This response is only received by the 
phone in this release. The user is notified 
if this response is received.
415 Unsupported 
Media
See comments This response is only received by the 
phone in this release. The user is notified 
if this response is received.
420 Bad Extension See comments This response is only received by the 
phone in this release. The user is notified 
if this response is received.
If the phone does not understand the 
protocol extension specified in the 
Require field, the 420 Bad Extension 
response is generated.
4xx Response Supported? Comments