Hi Castillo, My two cents. As the provider I would not play early media for 404 case since I know the PSTN provider will do it. It should be possible to identify this special case in the coding level.
Thanks, Ryan -------------------------------------------------- From: "Iñaki Baz Castillo" <[EMAIL PROTECTED]> Sent: Tuesday, March 04, 2008 8:12 PM To: <[email protected]> Subject: [Sip-implementors] RFC 3398 - ISUP/SIP mapping: 404 -> Unallocatednumber ?? > Hi, when I receive an INVITE from my provider SIP_PSTN gateway I do a > lookup > in my internal ENUM. > If the E164 number is mapped to a local SIP user (client of mine) I look > for > it in the location server. > If the user is registered I forwad the INVITE and so... all OK. > > The problem is in the case the SIP user is not registered (by any reason). > Then my proxy replies "404 Not Found" to the provider SIP_PSTN gateway. > > RFC 3398 specifies that the ISUP mapped code for SIP "404" is: > > > ------------------------------------------------------------------------------------------------- > 1 Unallocated number > This number is not in the routing table or it has no path across the > ISDN > cloud (network). > 1. Check routing table to see it the number is available. > 2. Check to make sure the correct digits were dialed and it is a > valid number. > > ------------------------------------------------------------------------------------------------- > > So my PSTN provider replies with ISUP "Unallocated number" and the caller > provider "X" generates the typicall early media message to inform the > caller: > "Provider X informs you that the number you are calling doesn't exist" > > This is a big inconvenient since me, as telephony provider, am responsible > of > generating that early media message. In fact, when I receive a call to a > non > registered user I first reply with an own 183 Session Progress: > "My provider informs you that the number you are calling is not available > now" > After the 183 I send a 404, so the gateway mappes it to "Unallocated > number" > and the caller provider adds its own early media message... the caller > listens to two early messages (mine first and him provider's one later)!! > > > > But the callee DOES exist, the only it occurs is that the SIP user is not > registered, just it. The number DOES exist in my system, so I think it > would > be better if my provider gateway would map the 404 to any of those ISUP > causes: > > > ------------------------------------------------------------------------------------------------- > 3 No route to destination. > The dialed number is in the routing plan, but there is no physical > route > to the destination. > 1. The PRI D-Channel may be down at one end or the other. > 2. The span or WAN is not connected correctly. > > ------------------------------------------------------------------------------------------------- > > > ------------------------------------------------------------------------------------------------- > 20 Subscriber Absent. > Used when a mobile station has logged off, radio contact is not > obtained with a mobile station or if a personal telecommunications > user is temporarily not addressable at any user-network interface. > > ------------------------------------------------------------------------------------------------- > > > ------------------------------------------------------------------------------------------------- > 27 Destination Out-of-Order. > This is a working number, but the span to the destination is not > active or there is a problem sending messages to this destination. > > ------------------------------------------------------------------------------------------------- > > > > Unfortunatelly any of the above ISUP causes (decimal 3, 20, 27) exist as a > SIP > code mapping in RFC 3398. > As a very dirty solution I'm using now this RFC3398 mapping: > > 502 Bad gateway ---> 38 Network out of order > > > ------------------------------------------------------------------------------------------------- > 38 Network Out-of-Order. > Indicates that the network is not functioning correctly and that > the > condition is likely to last a relatively long period of time. > > ------------------------------------------------------------------------------------------------- > > So if the caller is a movile he will be first listen to my provider early > message, and later he will see "network failure" (or similar) into its > screen. It's dirty but it's the best option I've found. > > > Any suggestion to handle it more correctly? In short, I can't reply with > "404" > since the caller will listen two early media messages and he will think > that > the number doesn't exist. > > > Thanks for any help. > > -- > Iñaki Baz Castillo > [EMAIL PROTECTED] > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
