Jim writes:

I think there's general consensus that end users should not see core telco routing data.

Here we are at the point: why should they? The basic question discussed here is VoIP (aka SIP) on the public Internet and VoIP (aka NGN - or NWOS - new wine in ols skins - Lawrence) in walled gardens. If you implement VoIP on the Internet you basically need SIP URIs (AoRs) and proxies (SVR records in the DNS) to reach this SIP AoRs. If you do not have these ENUM in e164.arpa Is completely useless. If you have these, you basically do not need telcos for routing E.164 numbers. If you implement VoIP in NGN walled gardens you basically have two choices: a - they use an extranet (e.g. GRX from GSM-A) to interconnect between the walled gardens the choice of the routing mechanism (ENUM or something else) in this case is purely a decision of the extranet provider (e.g. GSM-A) and also limited to the club. End-user will not have access to these data. What you need here is a mapping E.164 number to operator. b - they use the public Internet to interconnect, so they need some kind of public AoRs (URIs) (e.g. +xxx@be.prov.net )to address the ingress border elements (these finally have public IP-adresses). So they may use some kind of ENUM in a commonly agreed upon tree, which could be any root e.g. e164.stastny.com) Subscribers may may be able to query the tree or not, but it will be useless because they cannot access the border elements directly. The bsaic question here is: do the carriers agree on ONE tree or will there be a wood of trees? But this is not a big issue if all con-federations have a basic rule: any participating carrier is obliged to enter only E.164 numbers he is serving. Then automatically not overlaps exist between the trees (expect carriers participating in more then one tree) and therefor the trees could be merged easily later. Back to the original question:

I think there's general consensus that end users should not see core telco routing data.

Normal end-users give a s**t anyway about technical details if making a call, so why should the be prevented to see core telco routing data. They real problem of telcos is to prevent OTHER TELCOS to see their data, primarily to see how many subscribers they really have ;-) They funny thing here is that competitors know these facts anyway, but it's nice to pretend to have secrets. Now we are at the basic problem: Is there a way to feed data into a database used by competitors to find out which numbers a given telco hosts without disclosing to the competitors which numbers this telco hosts? A cretan says: all cretans are liars. True or false? This is the problem we have to solve ;-) -richard

-----Original Message----- From: Jim Reid [mailto:jim@rfc1035.com] Sent: Tuesday, December 14, 2004 9:48 PM To: Richard Shockey Cc: Stastny Richard; Marco bernardi; Andrzej Bartosiewicz; Carsten Schiefner; enum-wg@ripe.net Subject: Re: AW: [enum-wg] COCOM & ENUM ...

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"Richard" == Richard Shockey <richard@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?