SIP 202 Accepted vs 487 Request Terminated
SIP 202 (Accepted) is a 2xx Success response, while 487 (Request Terminated) is a 4xx Client Failure response. 202 indicates that the request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests. In contrast, 487 means that the request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
Description
The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
Quand vous le voyez
After sending a REFER request for call transfer. The transfer target acknowledges receipt but hasn't completed the transfer yet.
Comment résoudre
Wait for a NOTIFY to learn the outcome of the referred action. If no NOTIFY arrives, check subscription state and network connectivity.
Description
The request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
Quand vous le voyez
When the caller hangs up before the callee answers (CANCEL sent for pending INVITE). This is normal call abandonment.
Comment résoudre
No fix needed — the caller intentionally terminated the request. This is normal behavior.
Différences clés
202 is a 2xx Success response, while 487 is a 4xx Client Failure response.
SIP 202: The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
SIP 487: The request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
You encounter 202 when after sending a REFER request for call transfer. The transfer target acknowledges receipt but hasn't completed the transfer yet.
You encounter 487 when when the caller hangs up before the callee answers (CANCEL sent for pending INVITE). This is normal call abandonment.
Quand utiliser lequel
For 202 (Accepted): Wait for a NOTIFY to learn the outcome of the referred action. If no NOTIFY arrives, check subscription state and network connectivity. For 487 (Request Terminated): No fix needed — the caller intentionally terminated the request. This is normal behavior.