SIP 100 Trying vs 412 Conditional Request Failed
SIP 100 (Trying) is a 1xx Provisional response, while 412 (Conditional Request Failed) 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, 412 means that the precondition given in the request was not met. Used with SIP event state publication (RFC 3903).
Descrição
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.
Quando você o vê
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.
Como corrigir
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
Descrição
The precondition given in the request was not met. Used with SIP event state publication (RFC 3903).
Quando você o vê
When a PUBLISH request includes an If-Match header with an entity tag that does not match the current state on the server.
Como corrigir
Refresh the entity tag by performing a new PUBLISH without If-Match, then use the returned SIP-ETag for subsequent updates.
Diferenças principais
100 is a 1xx Provisional response, while 412 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 412: The precondition given in the request was not met. Used with SIP event state publication (RFC 3903).
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 412 when when a PUBLISH request includes an If-Match header with an entity tag that does not match the current state on the server.
Quando usar qual
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 412 (Conditional Request Failed): Refresh the entity tag by performing a new PUBLISH without If-Match, then use the returned SIP-ETag for subsequent updates.