SIP 181 Call Is Being Forwarded vs 413 Request Entity Too Large
SIP 181 (Call Is Being Forwarded) is a 1xx Provisional response, while 413 (Request Entity Too Large) is a 4xx Client Failure response. 181 indicates that a proxy server may send this to indicate that the call is being forwarded to a different set of destinations. In contrast, 413 means that the server is refusing to process the request because the message body is larger than the server is willing to accept.
Description
A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
When You See It
When the callee has call forwarding enabled and the request is being redirected to another number or device.
How to Fix
No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings.
Description
The server is refusing to process the request because the message body is larger than the server is willing to accept.
When You See It
When sending a SIP message with a body (SDP, XML, etc.) that exceeds the server's size limit.
How to Fix
Reduce the size of the message body. For SDP, minimize codec offers or remove unnecessary attributes.
Key Differences
181 is a 1xx Provisional response, while 413 is a 4xx Client Failure response.
SIP 181: A proxy server may send this to indicate that the call is being forwarded to a different set of destinations.
SIP 413: The server is refusing to process the request because the message body is larger than the server is willing to accept.
You encounter 181 when when the callee has call forwarding enabled and the request is being redirected to another number or device.
You encounter 413 when when sending a SIP message with a body (SDP, XML, etc.) that exceeds the server's size limit.
When to Use Which
For 181 (Call Is Being Forwarded): No action needed. The call is being redirected. If forwarding is unintended, the callee should update their forwarding settings. For 413 (Request Entity Too Large): Reduce the size of the message body. For SDP, minimize codec offers or remove unnecessary attributes.