SIP 100 Trying vs 486 Busy Here
SIP 100 (Trying) is a 1xx Provisional response, while 486 (Busy Here) is a 4xx Client Failure response. 100 indicates that the request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses. In contrast, 486 means that the callee's end system was contacted successfully but the callee is currently not willing or able to take additional calls at this end system.
설명
The request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses.
이 코드를 보게 되는 경우
Immediately after sending an INVITE. The proxy has received the call and is searching for the callee. This is the SIP equivalent of a dial tone.
해결 방법
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
설명
The callee's end system was contacted successfully but the callee is currently not willing or able to take additional calls at this end system.
이 코드를 보게 되는 경우
When the callee is already on a call and does not have call waiting. The user explicitly rejected the call, or all lines are in use.
해결 방법
Wait and try again later. The callee may become available when their current call ends. Consider leaving a voicemail if available.
주요 차이점
100 is a 1xx Provisional response, while 486 is a 4xx Client Failure response.
SIP 100: The request has been received by the next-hop server and an unspecified action is being taken to process it. The UAC should expect additional responses.
SIP 486: The callee's end system was contacted successfully but the callee is currently not willing or able to take additional calls at this end system.
You encounter 100 when immediately after sending an INVITE. The proxy has received the call and is searching for the callee. This is the SIP equivalent of a dial tone.
You encounter 486 when when the callee is already on a call and does not have call waiting. The user explicitly rejected the call, or all lines are in use.
언제 어떤 것을 사용할지
For 100 (Trying): No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration. For 486 (Busy Here): Wait and try again later. The callee may become available when their current call ends. Consider leaving a voicemail if available.