AW: [enum-wg] COCOM & ENUM ...
Jim Reid jim at rfc1035.com
Tue Dec 14 21:48:14 CET 2004
>>>>> "Richard" == Richard Shockey <richard at shockey.us> writes: Richard> HUH are you kidding ... its is because of the basic and Richard> orthogonal conflict between what carriers need and want Richard> and what end users need and want. I'm not convinced that really is (or will be) the case. Alice is an end user with SIP applications that lookup E.164 numbers in public e164.arpa tree to find SIP gateways. Fast-forward a few years. Bob's a telco doing VoIP and SIP and using DNS lookups of E.164 numbers to route calls in his net and to other operators. What's the difference? The applications are both using the DNS to figure out how to find the right SIP server for some VoIP session (or whatever). Carol sells SIP server and client software. Will she want to develop, sell and support different versions of the same thing to Alice and Bob? Meantime, what if Bob wants to dump calls from his network to Alice on Alice's internet SIP server so that he doesn't have to pay termination charges to Alice's telco? Richard> Either bifurcate the tree at Tier one into two non Richard> terminal NAPTR records (public & carrier)..which BTW will Richard> break SIP applications since there is no standards any Richard> where on how to deal with this. Maybe there should be a standard on this? :-) Though the bifurcation could also be realised with split DNS. Richard> Two merge T1 and T2 into the national registry which Richard> makes the registry operator the central repository for Richard> ALL SIP routing data for both the carriers and end Richard> users...which at least preserves the existing model of Richard> the DNS responds with an "answer" ..the carriers can Richard> still use non terminal records but normal SIP CUA's would Richard> simply ignore them. This is too awful for words. I think there's general consensus that end users should not see core telco routing data. Richard> Three have two entirely separate trees ..e164.arpa for Richard> number holders e164.int for carriers. The .int tree Richard> could be designed to look into apra for answers it is not Richard> authoritative for. Problem solved. This gets very ugly very quickly IMO. Operationally such setups would be very brittle and near-impossible to debug. Richard> oh no we're not going down that rat hole of split DNS It's no more of a rat hole than having yet another domain name with funky forwarding/fallback on failure modes between the 2 (or more?) domain names that you seem to favour. I suspect these could be much, much worse to administer and operate than a split DNS solution. It would be good to get hard data on the pros and cons of both approaches. And any others for that matter. Even better would be to get that data before a lasting decision is made. :-) Richard> you forget the basic consumer or PBX edge ENUM resolver Richard> has no need to see the carrier data. I've not forgotten that at all. I think you have misunderstood me. Well, I have an accent.... :-) Suppose some company is writing ENUM-aware telephony software that needs to figure out which SIP server to use when terminating a call for some E.164 number. [Note the deliberate hand-waving about where that software lives or which net the device is on.] How many DNS lookups and domain names is it going to need to do that? From a developer's perspective, how will the software know which net it's in so it knows which domain names to try (and in what order)? >> A centralised database could well mean telcos expose their >> customer and call routing data to each other. Which is unlikely >> to get much acceptance. Richard> Well then you have argued that LNP databases dont work Richard> and I have it on good authority that they do :-) You would say that, wouldn't you? :-) Does a number portability database disclose to TelcoA how TelcoB routes calls around its networK?
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