[Serusers] Getting rid of SIP URI in Caller ID

Jiri Kuthan jiri at iptel.org
Tue Jul 10 13:13:33 CEST 2007


At 16:19 09/07/2007, Charles Ulrich wrote:
>On Friday 06 July 2007 04:41, Jiri Kuthan wrote:
>> Hi Charles,
>>
>> Is the 'voip edition' somewhere available? I would be eager to give
>> it a try on my WRT too.
>
>Sure. There's no direct link, so you have to click through the following 
>trail of links:
>
>* Go to www.dd-wrt.com
>* Downloads
>* stable
>* dd-wrt.v23 SP2
>* voip
>* dd-wrt.v23_voip.bin
>
>Use this if you have a WRT54Gv4 or WRT54GL, otherwise check the 
>documentation to find out which firmware image you need. DD-WRT works 
>on a couple of other router brands too, such as Buffalo, Belkin, and 
>ASUS.
>
>> I'm a bit sceptical how much we can do about it, since the URIs are
>> part of the SIP protocol machinery and it is up to discretion of a
>> telephone implementation to show what it wants to show (there is no
>> standard for what a telephone shall display).
>
>You mean SIP doesn't have some kind of caller ID header? When these 
>phones are registered directly with Asterisk, caller ID works exactly 
>like a legacy non-SIP phone: Only a name and a number (or extension) 
>appear on the display on an incoming call. Using SER as a proxy, we get 
>the SIP URI instead of simply the telephone number.

perhaps you are using Asterisk in H.323 mode? Messages from asterisk,
as long as in SIP mode, follow the same protocol as SER does...


>> IMO you are then left with experimenting and changing SIP requests in
>> a way that increases the chance that the phone shows what you want to
>> be shown. There is no guarantee however it will work for all phones
>> in a consistent way.
>>
>> If I were you, I would try appending P-asserted-identity or
>> Remote-Party-ID header fields with tel URIs (benefit: use of a header
>> field does not change request URI, which might have side effects
>> otherwise, and use of TEL URI eliminates the domain). If that does
>> not work, I would try to put TEL URI in request-URI.
>
>I'll see what I can come up with but it looks like using SER as an 
>outbound proxy isn't quite solving the main issue (NAT traversal) 
>anyway.

Indeed it cannot. You have to use rtp-proxy in addition to SER -- SER
does only signaling, rtp-proxy fixes media.

-jiri


>Thanks!
>-- 
>Charles Ulrich
>Ideal Solution, LLC -- http://www.idealso.com



--
Jiri Kuthan            http://iptel.org/~jiri/




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