SIP 182 Queued vs 400 Bad Request
SIP 182 (Queued) is a 1xx Provisional response, while 400 (Bad Request) is a 4xx Client Failure response. 182 indicates that the called party is temporarily unavailable but the server has decided to queue the call rather than reject it. The call will be attempted when the callee becomes available. In contrast, 400 means that the request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
Description
The called party is temporarily unavailable but the server has decided to queue the call rather than reject it. The call will be attempted when the callee becomes available.
When You See It
In call center or queuing scenarios where the callee is busy but the system holds the call in a queue.
How to Fix
Wait for the call to be dequeued. If queuing is not desired, configure the server to reject calls instead of queuing them.
Description
The request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
When You See It
When the SIP message has syntax errors, missing required headers, or invalid header values.
How to Fix
Review the SIP message for syntax errors. Check required headers (To, From, Call-ID, CSeq, Via, Max-Forwards) and ensure proper formatting.
Key Differences
182 is a 1xx Provisional response, while 400 is a 4xx Client Failure response.
SIP 182: The called party is temporarily unavailable but the server has decided to queue the call rather than reject it. The call will be attempted when the callee becomes available.
SIP 400: The request could not be understood due to malformed syntax. The client should not repeat the request without modifications.
You encounter 182 when in call center or queuing scenarios where the callee is busy but the system holds the call in a queue.
You encounter 400 when when the SIP message has syntax errors, missing required headers, or invalid header values.
When to Use Which
For 182 (Queued): Wait for the call to be dequeued. If queuing is not desired, configure the server to reject calls instead of queuing them. 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.