To expand: the problem is the VoIP client being able to *furnish* an approximation of where it is, to permit the selection of the proper Public Safety Access Point (or equivalent).
The fact is: Skype is not interested where the client is located. They dont care. Well, Skype is not a defined standard but skype exits. There are lots of VoIP telefones out. Do you really want to call them back in to change the software? How about tunnels? Do we have to rewrite all tunnel software? How do I know where that client with ip 192.168.48.226 (me) is located? NAT behind NAT behind NAT, some packet-radio links and IPv6 over ISODE tunnels and all that via SNA through an IBM company link. No, my network is not really that complicated - but I thought of a hamradio friend who is working at the Georg-Von-Neumayer Antarctic Base. Or simply think of an IP-phone used aboard an airplane moving from Berlin to Abitibi-Témiscamingue (Québec). You cannot change all phones out there. You cannot change all public domain telephone software. All you can do is tell your sip office to direct any 911 or 112 calls directly to the Vatican. Hopefully they will have someone speaking the right language. Probably they will have the right personnel to deal with this kind of emergency. A buddhist monastery in Tibet would do nicely too. I think that is where the chinese route their calls :)
If each end-router supplied that data, through *some* easily queriable protocol, such clients could retrieve it, and then decide (in some fashion) where to send Emergency Services Request calls (or furnish it to their carrier, if they have one, for similar purposes).
I know where my DSLAM is located. That is some 80 KM or say 40 miles away from here. My link to that router is via PPPoE. There are some switches, bridges and dont ask me what other hardware in between. All that router knows is, I am one of 4K costumers connected. It does not care where I plug in my DSL modem as long as I stay some 150 KM around Frankfurt. There are some 60 police callcenters within this area. I had already the experience what it means when my GSM phone connects the wrong one of them. Of course whe have 112 service for cellurlar phones - only they wont help you if you need them. Just take the final two bytes of your ip and connect one of them randomly. You probably hit the right one. Why dialing a number? How about dialing an ip? 156.106.192.163 that is www.itu.int. They are the right one to ask about telephone regulations anyway. Cheers, Peter -- Peter und Karin Dambier Graeffstrasse 14 D-64646 Heppenheim +49-6252-671788 (Telekom) +49-6252-599091 (O2 Genion) +1-360-226-6583-9738 (INAIC) peter@peter-dambier.de www.peter-dambier.de peter-dambier.site.voila.fr