SIP 180 Ringing vs 483 Too Many Hops
SIP 180 (Ringing) is a 1xx Provisional response, while 483 (Too Many Hops) 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, 483 means that the Max-Forwards header has reached zero, indicating the request has passed through too many proxies.
Description
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.
When You See It
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
How to Fix
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.
Description
The Max-Forwards header has reached zero, indicating the request has passed through too many proxies.
When You See It
When a request traverses more proxies than the Max-Forwards counter allows (default 70). Often indicates a routing loop.
How to Fix
Check for routing loops. If the path is legitimately long, increase Max-Forwards. Usually indicates misconfigured routing.
Key Differences
180 is a 1xx Provisional response, while 483 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 483: The Max-Forwards header has reached zero, indicating the request has passed through too many proxies.
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 483 when when a request traverses more proxies than the Max-Forwards counter allows (default 70). Often indicates a routing loop.
When to Use Which
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 483 (Too Many Hops): Check for routing loops. If the path is legitimately long, increase Max-Forwards. Usually indicates misconfigured routing.