SIP 180 Ringing vs 487 Request Terminated
SIP 180 (Ringing) is a 1xx Provisional response, while 487 (Request Terminated) is a 4xx Client Failure response. 180 indicates that the UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end. 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 UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end.
When You See It
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
How to Fix
No fix needed — the callee's device is ringing. If the call never connects after ringing, check the callee's device or call forwarding settings.
Description
The request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
When You See It
When the caller hangs up before the callee answers (CANCEL sent for pending INVITE). This is normal call abandonment.
How to Fix
No fix needed — the caller intentionally terminated the request. This is normal behavior.
Key Differences
180 is a 1xx Provisional response, while 487 is a 4xx Client Failure response.
SIP 180: The UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end.
SIP 487: The request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
You encounter 180 when during call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
You encounter 487 when when the caller hangs up before the callee answers (CANCEL sent for pending INVITE). This is normal call abandonment.
When to Use Which
For 180 (Ringing): No fix needed — the callee's device is ringing. If the call never connects after ringing, check the callee's device or call forwarding settings. For 487 (Request Terminated): No fix needed — the caller intentionally terminated the request. This is normal behavior.