SIP 204 No Notification vs 439 First Hop Lacks Outbound Support
SIP 204 (No Notification) is a 2xx Success response, while 439 (First Hop Lacks Outbound Support) is a 4xx Client Failure response. 204 indicates that the request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request. In contrast, 439 means that the first outbound proxy does not support the SIP outbound mechanism (RFC 5626) that the UA is trying to use.
คำอธิบาย
The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
เมื่อคุณพบเห็น
When subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
วิธีแก้ไข
No fix needed. The subscription was accepted but there is no state change to notify about yet.
คำอธิบาย
The first outbound proxy does not support the SIP outbound mechanism (RFC 5626) that the UA is trying to use.
เมื่อคุณพบเห็น
When a UA configured for SIP outbound connects to a proxy that doesn't support the outbound option-tag.
วิธีแก้ไข
Upgrade the outbound proxy to support RFC 5626, or configure the UA to not require outbound support.
ความแตกต่างหลัก
204 is a 2xx Success response, while 439 is a 4xx Client Failure response.
SIP 204: The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
SIP 439: The first outbound proxy does not support the SIP outbound mechanism (RFC 5626) that the UA is trying to use.
You encounter 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
You encounter 439 when when a UA configured for SIP outbound connects to a proxy that doesn't support the outbound option-tag.
ควรใช้อันไหนเมื่อไร
For 204 (No Notification): No fix needed. The subscription was accepted but there is no state change to notify about yet. For 439 (First Hop Lacks Outbound Support): Upgrade the outbound proxy to support RFC 5626, or configure the UA to not require outbound support.