Cisco SIP IP Phone Administrator's Manual page 105

Appendix A SIP Compliance with RFC 3261 Information
4xx Response
408 Request
Timeout
409 Conflict
410 Gone
411 Length
Required
413 Request Entity
Too Large
414
Request—URL
Too Long
415 Unsupported
Media
420 Bad Extension
Supported?
See comments
See comments
See comments
See comments
See comments
See comments
See comments
See comments
Comments
The SIP phone does not generate a 408 Request
Timeout response. For an incoming response, the
gateway initiates a graceful call disconnect (during
which the caller hears a busy or fast busy tone)
before clearing the call request.
This response is received only by the phone in this
release.
The 409 Conflict response indicates that the
INVITE request could not be processed because of
a conflict with the current state of the resource. If
this response is received, the user is notified.
This response is received by the phone only in this
release.
The 410 Gone response indicates that a resource is
no longer available at the server and no forwarding
address is known.
This response is received by the phone only 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.
This response is received only 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.
This response is received only by the phone in this
release. The user is notified if this response is
received.
This response is received only by the phone in this
release. The user is notified if this response is
received.
This response is received only 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.
Cisco SIP IP Phone Administrator Guide
SIP Responses
A-5