If you mean the callee isn't registered in the sip sense, because the
phone isn't connected, but you know the number is assigned to someone,
then IMO 404 is not the right response. A better response is 480. And
this has nothing to do with 3398.
Paul
Iñaki Baz Castillo wrote:
> 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.
>
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