Imran Saleem <imran....@gmail.com> writes: > Considering the above point Is there any reference in RFC stating that any > "out of dialog messages" sent must be responded back with > 481.(Call/Transaction > Does Not Exist).
How an out of dialog message should be responded to is determined by the definition of the message's method. For instance, an INVITE or SUBSCRIBE can create a dialog, and so can be responded to successfully. A BYE received whose Call-Id is unknown should receive a 481 response, as should a CANCEL with an unknown Call-Id. > Is it mandatory or optional to send back 481 for a scenario in which > UAS doesn't know how to handle the transaction. What do you mean by "doesn't know how to handle the transaction"? Generally, a request will receive a 481 response when the server understands the method, and the definition of the method requires a 481 response. Look at RFC 3261 sections 21.4 and 21.5 to determine the statuses to use for various error situations. For example, 400 is used when the server cannot parse the requests completely. 501 is used when the server can parse the request but does not implement the method (for any request). Dale _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
