Sunday, April 24, 2005

For the avoidance of doubt: No SIP URI - No ENUM 

The recent discussion on the requiem for the dead SIP caused a lot of confusion, including myself. Or as Martin said: I like a controversy, because that’s when we learn things.

My original post was triggered by Martin, where he said, the VoB is dead, and he also clarified this in his recent post:

The Vob (a provisionless SIP-speaking voice network) is dead. Not even sleeping. SIP will be embedded inside other virtual networks (e.g. IMS, aka “TDM and SS7 on IP”). But they will be overlayed with a ton of proprietary and closed stuff that will make any SIP embedded somewhat irrelevant.
I also cited Aswath and he obviously got this in the wrong thoat and be talked at cross-purposes for some time. He meant the SIP protocol suite, I meant the the provision of public and open SIP services on the Internet, providing you with a publicly accessible SIP URI.

Henry Sinnreich has stated many times to everybody wanting to listen or not:

IP Telephony without providing the end-user with a SIP URI is not considered Internet Telephony.

SIP was developed by the IETF and modelled after the e-mail protocol suite to be implemented on the public Internet end-to-end.

Today VoIP (SIP and H.323) is very successfully used within carriers networks, enterprises and offered to residential end-users also. But ALL of the enterprise and carrier implementations, also to residential end-user DO NOT provide end-users with a publicly available SIP or H323 URI. There is only some minor exceptions (e.g sipgate, FWD, etc.)

It is all walled garden and propriatory, starting with Yahoo!BB, Vonage, and ending with the VoIP" services from the various incumbents and cable operators jumping on the band-waggon). The NGN IMS currently specified by 3GPP, to be used also by ETSI TISPAN for fixed networks, will even have his own flavour of SIP (propriatory extensions - sic!) and will NOT provide you with public SIP URIs either.

Why? Ostensible for end-to-end QoS guaranties (ha!) and security reasons (called SBC promotion), but in reality because if you deliver a call to a public SIP URI without an interconnect agreement you are not able to charge terminating fees. This is especially a horrible idea for mobile operators in Europe, because most of them live on this (beside on living on the useful id.. ah parents of kids using SMS).

They are planning to interconnect either on the PSTN (=E.164 numbers) or via IP with bilateral interconnect agreements, which is an adminstrative nightmare and very expensive (OPEX). This is BTW one of the reasons why I have serious technical problems with the implementation of IMS.

Why I am so keen on this issue?

Because linked with the death ah.. non availability of the SIP URI also the future of ENUM.

For ENUM the basic requirement is a public SIP URI and the reachability of the related SIP server on the public Internet. ENUM is part of the provision of the of the VoB.

No public SIP URIs = No ENUM. Period. End of story.

Thanks for explicitly stating your concern. But given your concern, shouldn't we be applauding those that offer publically available SIP URI, like sipgate and FWD. Why not fault the individual providers who do not follow this idea, rather than reject the whole thing? Why encourage a closed system before attempting both of these steps? Why giveup the fight so easily and decalre that Vob is dead?

Hence my disconnect.

Give up? Easily? Man, the answer to this will trigger another post ;-)

Well said - the interconnect agreements definitely will play a huge role. But... what about the telcos and regulators? Do you think they will allow Skype to win the game without putting any barriers? Look at the UAE and even Mexico (funny how Carlos Slim has one attitude re. VoIP in Mexico with Telmex and another complete opposite one in Brazil with Globo, but that's besides the point).

Also, before you give up 100% on IMS, isn't IMS an attempt at carriers to own the customer with the apps? They realize the $$$ they make with voice is going to keep on dropping, so time to look for other revenues.

So things are not so clear as they might seem. But ENUM will still find lots of places to be in, even if not (assuming your doomsday scenario) on the BIG network. Here's an example: ENUM as a dial plan technology for large enterprise VoIP deployments.
Telcos is one thing, regulatos another. For Regulators (who claim to be technology neutral) Skype is just another VoIP. Telcos have a mixed feeling: Sykpe is a competition, but basically along the lines of other virtual VoIP providers, but on the other hand it is also a push for broadband. So maybe the telco (access provider) approach could be: If you cannot fight them, join them.

IMS is basically a try of the mobile operators (now joined by the fixed operators in a desparate me-too approach) to keep up the (up to now very successful) lock-in of customers. The problem here is that with BB access via mobile the CUSTOMER has now the choice if he uses the IMS services or third-party services available on the Internet.

ENUM's prime use case is enterprises. The problem here is how to cross the chasm and find a bowling alley. How to tell enterprises that ENUM exists and that is is a benefit for them. The telcos will not tell them and also not the Soft-Switch (or watchamacallit) vendors do not tell them. So for ENUM proponenets how to jump over this information gap?
Sorry for the late entry... but if VoIP providers do not distribute SIP URI's, are they planning to? Obviously there must be a technical threshold that must be reached before VoIP service providers add the complexity necessary to be fully IP accessible.

Secondly, doesn't the lack of SIP URI's also alleviate the need for VoIP service providers to create peering agreements to expand call coverage? Doesn't this mean that the business models of firms such as Skype, Vonage and Packet8 are built around utilizing the PSTN, not replacing it? Originally, I attributed the lack of peering agreements as a result of a fragile VoIP industry seeking to protect revenues by preventing potential user migrations. After reading your comments, it seems that the reliance on the PSTN eliminates the need for cooperation altogether. Can't it be said then, that the lack of SIP URI's is causing a segmented, uncooperative industry that is preventing users from attaining the true savings associated with VoIP?

And finally, does Austria, Germany or Austrailia distribute SIP URIs? Is this a global phenominon or an American one?

Post a Comment

This page is powered by Blogger. Isn't yours?