SIP 100 Trying vs 422 Session Interval Too Small
SIP 100 (Trying) is a 1xx Provisional response, while 422 (Session Interval Too Small) 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, 422 means that the request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
คำอธิบาย
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.
เมื่อคุณพบเห็น
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.
วิธีแก้ไข
No fix needed — this is normal call setup behavior. If stuck on 100 Trying for too long, check network connectivity and proxy configuration.
คำอธิบาย
The request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
เมื่อคุณพบเห็น
When using SIP session timers (RFC 4028) and the proposed session refresh interval is below the server's minimum.
วิธีแก้ไข
Increase the Session-Expires value to at least the value indicated in the Min-SE header of the 422 response.
ความแตกต่างหลัก
100 is a 1xx Provisional response, while 422 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 422: The request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
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 422 when when using SIP session timers (RFC 4028) and the proposed session refresh interval is below the server's minimum.
ควรใช้อันไหนเมื่อไร
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 422 (Session Interval Too Small): Increase the Session-Expires value to at least the value indicated in the Min-SE header of the 422 response.