SIP 302 Moved Temporarily vs 503 Service Unavailable
SIP 302 (Moved Temporarily) is a 3xx Redirection response, while 503 (Service Unavailable) is a 5xx Server Failure response. 302 indicates that the callee has temporarily moved to a different address. The client should retry the request at the Contact address but continue using the original URI for future requests. 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.
Description
The callee has temporarily moved to a different address. The client should retry the request at the Contact address but continue using the original URI for future requests.
When You See It
When a user is temporarily reachable at a different location, such as when traveling or using a different device.
How to Fix
Redirect the current call to the Contact URI provided, but keep the original URI for future requests.
Description
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.
When You See It
During server overload, maintenance windows, or when the server is rate-limiting requests. Common during traffic spikes.
How to Fix
Wait for the time specified in the Retry-After header. If persistent, check server capacity and consider load balancing across multiple SIP proxies.
Key Differences
302 is a 3xx Redirection response, while 503 is a 5xx Server Failure response.
SIP 302: The callee has temporarily moved to a different address. The client should retry the request at the Contact address but continue using the original URI for future requests.
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 302 when when a user is temporarily reachable at a different location, such as when traveling or using a different device.
You encounter 503 when during server overload, maintenance windows, or when the server is rate-limiting requests. Common during traffic spikes.
When to Use Which
For 302 (Moved Temporarily): Redirect the current call to the Contact URI provided, but keep the original URI for future requests. 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.