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.
Descrição
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.
Quando você o vê
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
Como corrigir
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.
Descrição
The request was terminated by a BYE or CANCEL. The original request was cancelled before it could be completed.
Quando você o vê
When the caller hangs up before the callee answers (CANCEL sent for pending INVITE). This is normal call abandonment.
Como corrigir
No fix needed — the caller intentionally terminated the request. This is normal behavior.
Diferenças principais
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.
Quando usar qual
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.