Table E-3 SIP Responses
SIP Response
|
Meaning
|
Supported?
|
Cisco SPS Action
|
1xx Response—Information Responses
|
|
100
|
Trying
|
Action is being taken on behalf of the caller, but the called party is not yet located.
|
Yes
|
Generates and forwards this response for an incoming INVITE. Upon receiving this response, waits for a 180 Ringing, 183 Session progress, or 200 OK response.
|
180
|
Ringing
|
Called party is located and is being notified of the call.
|
Yes
|
—
|
181
|
Call is being forwarded
|
Call is being rerouted to another destination.
|
See Cisco SPS action
|
Forwards these responses.
|
182
|
Queued
|
Called party is not currently available or elects to queue the call rather than reject it.
|
183
|
Session progress
|
System performs inband alerting for the caller.
|
Does not generate this message. Receives the message and forwards it upstream.
|
2xx Response—Successful Responses
|
|
200
|
OK
|
Request has been successfully processed. The action taken depends on the request made.
|
Yes
|
Generates this response to a REGISTER or CANCEL request. Otherwise forwards this response.
|
3xx Response—Redirection Responses
|
|
300
|
Multiple choices
|
Address resolves to more than one location. All locations are provided and the user or UA can select which location to use.
|
Yes
|
In redirect mode, generates this response. In proxy mode, generates or forwards this response.
|
301
|
Moved permanently
|
User is no longer available at the specified location. An alternate location is included in the header.
|
Yes
|
Forwards this response.
|
302
|
Moved temporarily
|
User is temporarily unavailable at the specified location. An alternate location is included in the header.
|
Yes
|
In redirect mode, generates this response when it locates a matching registration. In proxy mode, generates and forwards this response.
|
305
|
Use proxy
|
Caller must use a proxy to contact the called party.
|
Yes
|
—
|
380
|
Alternative service
|
Call is unsuccessful, but alternative services are available.
|
No
|
—
|
4xx Response—Request Failure Responses
|
|
400
|
Bad Request
|
Request can not be understood because of an illegal format.
|
Yes
|
Generates and forwards this response.
|
401
|
Unauthorized
|
Request requires user authentication.
|
Yes
|
Forwards this response. If it is configured as a registrar and authentication is enabled, generates this response.
|
402
|
Payment required
|
Payment is required for server to complete the call.
|
See Cisco SPS action
|
Generates these responses in registrar mode and if proxied by the proxy server.
|
403
|
Forbidden
|
Server has received and understood the request but will not provide the service.
|
404
|
Not found
|
Server has definite information that the user does not exist in the specified domain.
|
Yes
|
Generates and forwards this response.
|
405
|
Method not allowed
|
Method specified in the request is not allowed. The response contains a list of allowed methods.
|
See Cisco SPS action
|
Forwards these responses.
|
406
|
Not acceptable
|
Requested resource can generate only responses that have unacceptable content as specified in the accept header of the request.
|
407
|
Proxy authentication required
|
Similar to the 401 Unauthorized response, but client must first authenticate itself with the proxy.
|
Yes
|
Forwards this response. If authentication is enabled, generates this response.
|
408
|
Request timeout
|
Server could not produce a response before the expiration timeout.
|
See Cisco SPS action
|
Generates and forwards these responses.
|
409
|
Conflict
|
Request cannot be processed because of a conflict with the current state of the resource.
|
410
|
Gone
|
A resource is no longer available at the server and no forwarding address is known.
|
See Cisco SPS action
|
Forwards this response.
|
411
|
Length required
|
User refuses to accept the request without a defined content length.
|
Yes
|
Forwards this response.
|
413
|
Request entity too large
|
Server refuses to process the request because it is larger than the server is willing or able to process. If a retry after header field is contained in this response, the user can attempt the call once again in the retry time provided.
|
See Cisco SPS action
|
Forwards this response.
|
414
|
Request-URI too long
|
Server refuses to process the request because the Request-URI is too long for the server to interpret.
|
Yes
|
Generates and forwards this response.
|
415
|
Unsupported media
|
Server refuses to process the request because the format of the body is not supported by the destination endpoint.
|
Yes
|
Forwards this response.
|
420
|
Bad extension
|
Server cannot understand the protocol extension indicated in the Require header.
|
Yes
|
Generates and forwards this response.
|
480
|
Temporarily unavailable
|
Called party was contacted but is temporarily unavailable.
|
Yes
|
Forwards this response. Generates the response if preauthentication is enabled and fails.
|
481
|
Call leg/transaction does not exist
|
Server ignores the request because it is either a BYE for which there is no matching leg ID or a CANCEL for which there is no matching transaction.
|
Yes
|
Generates and forwards these responses.
|
482
|
Loop detected
|
Server received a request that includes itself in the path.
|
483
|
Too many hops
|
Server received a request that requires more hops than allowed by the Max-Forwards header.
|
484
|
Address incomplete
|
Server received a request that contains an incomplete address.
|
See Cisco SPS action
|
Forwards this response.
|
485
|
Ambiguous
|
Server received a request that contains an ambiguous called-party address. It can provide possible alternative addresses.
|
See Cisco SPS action
|
Forwards this response.
|
486
|
Busy here
|
Called party was contacted but his or her system is unable to take additional calls.
|
487
|
Busy here; request cancelled
|
Request was terminated by a BYE or CANCEL request.
|
No
|
—
|
488
|
Not acceptable media
|
An error in handling the request occurred.
|
See Cisco SPS action
|
Forwards this response.
|
5xx Response—Server Failure Responses
|
|
500
|
Server internal error
|
Server or gateway encountered an unexpected error that prevents it from processing the request.
|
Yes
|
Generates and forwards these responses.
|
501
|
Not implemented
|
Server or gateway does not support the functions required to complete the request.
|
502
|
Bad gateway
|
Server or gateway received an invalid response from a downstream server.
|
See Cisco SPS action
|
Forwards these responses.
|
503
|
Service unavailable
|
Server or gateway is unable to process the request due to an overload or maintenance problem.
|
504
|
Gateway timeout
|
Server or gateway did not receive a timely response from another server (such as a location server).
|
505
|
Version not supported
|
Server or gateway does not support the version of the SIP protocol used in the request.
|
Yes
|
6xx Response—Global Responses
|
|
600
|
Busy everywhere
|
Called party was contacted but is busy and cannot take the call at this time.
|
See Cisco SPS action
|
Forwards these responses.
|
603
|
Decline
|
Called party was contacted but cannot or does not want to participate in the call.
|
604
|
Does not exist anywhere
|
Server has authoritative information that the called party does not exist in the network.
|
606
|
Not acceptable
|
Called party was contacted, but some aspect of the session description was unacceptable.
|
Feedback
SIP Transport Layer Protocols
