SIP 100 Trying vs 600 Busy Everywhere
SIP 100 (Trying) is a 1xx Provisional response, while 600 (Busy Everywhere) is a 6xx Global 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, 600 means that the callee's end system was contacted successfully but the callee is busy and does not wish to take the call at this time. Unlike 486 (Busy Here), this is a definitive response.
Description
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.
Quand vous le voyez
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.
Comment résoudre
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
Description
The callee's end system was contacted successfully but the callee is busy and does not wish to take the call at this time. Unlike 486 (Busy Here), this is a definitive response.
Quand vous le voyez
When the callee has rejected the call on all devices. No other endpoints should be tried. The user is universally busy.
Comment résoudre
Wait and try again later. No alternative contact points exist. The callee must become available on their own.
Différences clés
100 is a 1xx Provisional response, while 600 is a 6xx Global 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 600: The callee's end system was contacted successfully but the callee is busy and does not wish to take the call at this time. Unlike 486 (Busy Here), this is a definitive response.
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 600 when when the callee has rejected the call on all devices. No other endpoints should be tried. The user is universally busy.
Quand utiliser lequel
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 600 (Busy Everywhere): Wait and try again later. No alternative contact points exist. The callee must become available on their own.