SIP 202 Accepted vs 580 Precondition Failure
SIP 202 (Accepted) is a 2xx Success response, while 580 (Precondition Failure) is a 5xx Server 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, 580 means that the server is unable or unwilling to meet some of the preconditions specified in the request for resource reservation.
Description
The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
When You See It
After sending a REFER request for call transfer. The transfer target acknowledges receipt but hasn't completed the transfer yet.
How to Fix
Wait for a NOTIFY to learn the outcome of the referred action. If no NOTIFY arrives, check subscription state and network connectivity.
Description
The server is unable or unwilling to meet some of the preconditions specified in the request for resource reservation.
When You See It
When using QoS preconditions (RFC 3312) and the network cannot guarantee the required quality of service for the media session.
How to Fix
Relax the precondition requirements or ensure the network path supports the required QoS. Consider removing precondition requirements for best-effort calls.
Key Differences
202 is a 2xx Success response, while 580 is a 5xx Server Failure response.
SIP 202: The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
SIP 580: The server is unable or unwilling to meet some of the preconditions specified in the request for resource reservation.
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 580 when when using QoS preconditions (RFC 3312) and the network cannot guarantee the required quality of service for the media session.
When to Use Which
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 580 (Precondition Failure): Relax the precondition requirements or ensure the network path supports the required QoS. Consider removing precondition requirements for best-effort calls.