SIP 100 Trying vs 604 Does Not Exist Anywhere
SIP 100 (Trying) is a 1xx Provisional response, while 604 (Does Not Exist Anywhere) 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, 604 means that the server has authoritative information that the user indicated in the Request-URI does not exist anywhere. Unlike 404, this is a definitive, global statement.
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 server has authoritative information that the user indicated in the Request-URI does not exist anywhere. Unlike 404, this is a definitive, global statement.
Quando você o vê
When the user definitively does not exist on any server in the network. The server has authoritative knowledge, not just local.
Como corrigir
The user does not exist. Verify the SIP URI or phone number. Unlike 404, retrying on other servers will not help.
Diferenças principais
100 is a 1xx Provisional response, while 604 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 604: The server has authoritative information that the user indicated in the Request-URI does not exist anywhere. Unlike 404, this is a definitive, global statement.
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 604 when when the user definitively does not exist on any server in the network. The server has authoritative knowledge, not just local.
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 604 (Does Not Exist Anywhere): The user does not exist. Verify the SIP URI or phone number. Unlike 404, retrying on other servers will not help.