SIP 202 Accepted vs 400 Bad Request
SIP 202 (Accepted) is a 2xx Success response, while 400 (Bad Request) 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, 400 means that the request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
説明
The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
このコードが表示される場合
After sending a REFER request for call transfer. The transfer target acknowledges receipt but hasn't completed the transfer yet.
解決方法
Wait for a NOTIFY to learn the outcome of the referred action. If no NOTIFY arrives, check subscription state and network connectivity.
説明
The request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
このコードが表示される場合
When the SIP message has syntax errors, missing required headers, or invalid header values.
解決方法
Review the SIP message for syntax errors. Check required headers (To, From, Call-ID, CSeq, Via, Max-Forwards) and ensure proper formatting.
主な違い
202 is a 2xx Success response, while 400 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 400: The request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
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 400 when when the SIP message has syntax errors, missing required headers, or invalid header values.
どちらをいつ使うか
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 400 (Bad Request): Review the SIP message for syntax errors. Check required headers (To, From, Call-ID, CSeq, Via, Max-Forwards) and ensure proper formatting.