Response Messages

Response messages are sent by servers to indicate the outcome of a request processed by a SIP server. SIP responses are categorized into six classes, based on their status codes: 

1xx (Provisional): Temporary responses that indicate the request is still being processed. 

2xx (Successful): Indicate that the request was successfully received, understood, and accepted. 

3xx (Redirection): Inform the client that further action needs to be taken, typically by sending the request to another endpoint. 

4xx (Client Error): Indicate an error on the client's part, such as a malformed request or unauthorized access. 

5xx (Server Error): Signify server failures when processing a valid request. 

6xx (Global Failure): Indicate that the request cannot be fulfilled at any server, suggesting a global failure in the request processing. 

Response messages play a vital role in SIP communication, providing feedback on request processing and guiding subsequent actions within SIP sessions.