SIP 100 Trying vs 503 Service Unavailable
SIP 100 (Trying) is a 1xx Provisional response, while 503 (Service Unavailable) is a 5xx Server 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, 503 means that the server is temporarily unable to process the request due to overloading or maintenance. The client should retry after the time indicated in the Retry-After header.
Deskripsi
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.
Ketika Anda Melihatnya
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.
Cara Memperbaiki
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
Deskripsi
The server is temporarily unable to process the request due to overloading or maintenance. The client should retry after the time indicated in the Retry-After header.
Ketika Anda Melihatnya
During server overload, maintenance windows, or when the server is rate-limiting requests. Common during traffic spikes.
Cara Memperbaiki
Wait for the time specified in the Retry-After header. If persistent, check server capacity and consider load balancing across multiple SIP proxies.
Perbedaan Utama
100 is a 1xx Provisional response, while 503 is a 5xx Server 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 503: The server is temporarily unable to process the request due to overloading or maintenance. The client should retry after the time indicated in the Retry-After header.
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 503 when during server overload, maintenance windows, or when the server is rate-limiting requests. Common during traffic spikes.
Kapan Menggunakan Yang Mana
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 503 (Service Unavailable): Wait for the time specified in the Retry-After header. If persistent, check server capacity and consider load balancing across multiple SIP proxies.