> Given the case where local transport is unable to > send a request due to the failure in establishing > the connection to the next hop, the condition must > be treated as 503 (Service Unavailable) status code. > But there is a requirement that transaction layer > must submit an ACK for this response as stated in > RFC3261, Section 17.1.1.1 Overview of INVITE Client > transaction:
The requirement does not apply to an internally generated 503 response (or whatever you use to communicate unable to send INVITE). > When in either the "Calling" or "Proceeding" states, reception of a > response with status code from 300-699 MUST cause the client > transaction to transition to "Completed". The client transaction > MUST pass the received response up to the TU, and the client > transaction MUST generate an ACK request, even if the transport is > reliable (guidelines for constructing the ACK from the response are > given in Section 17.1.1.3) and then pass the ACK to the transport > layer for transmission. > > So in the case where local transport has failed, > there is no point in submitting an ACK request to > the local transport as the 503 response was > received due to the failing local transport. > How would you suggest to approach this situation? Don't send an ACK if the 503 response was internally generated (if actually building such a response) instead of received. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
