SIP 202 Accepted vs 439 First Hop Lacks Outbound Support
SIP 202 (Accepted) is a 2xx Success response, while 439 (First Hop Lacks Outbound Support) is a 4xx Client Failure response. 202 indicates that the request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests. 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.
Описание
The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
Когда вы это видите
After sending a REFER request for call transfer. The transfer target acknowledges receipt but hasn't completed the transfer yet.
Как исправить
Wait for a NOTIFY to learn the outcome of the referred action. If no NOTIFY arrives, check subscription state and network connectivity.
Описание
The first outbound proxy does not support the SIP outbound mechanism (RFC 5626) that the UA is trying to use.
Когда вы это видите
When a UA configured for SIP outbound connects to a proxy that doesn't support the outbound option-tag.
Как исправить
Upgrade the outbound proxy to support RFC 5626, or configure the UA to not require outbound support.
Ключевые различия
202 is a 2xx Success response, while 439 is a 4xx Client Failure response.
SIP 202: The request has been accepted for processing but the processing has not been completed. Used primarily for REFER requests.
SIP 439: The first outbound proxy does not support the SIP outbound mechanism (RFC 5626) that the UA is trying to use.
You encounter 202 when after sending a REFER request for call transfer. The transfer target acknowledges receipt but hasn't completed the transfer yet.
You encounter 439 when when a UA configured for SIP outbound connects to a proxy that doesn't support the outbound option-tag.
Когда что использовать
For 202 (Accepted): Wait for a NOTIFY to learn the outcome of the referred action. If no NOTIFY arrives, check subscription state and network connectivity. For 439 (First Hop Lacks Outbound Support): Upgrade the outbound proxy to support RFC 5626, or configure the UA to not require outbound support.