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The IMS Debate

by Lee S. Dryburgh
01/12/2007

Editor's Note: Lee Dryburgh will be presenting and leading a live debate on IMS at O'Reilly's Emerging Telephony conference.

Operators are moving toward so called Next-Generation Networks (NGNs), which entail consolidating their traditional voice networks and other service delivery networks into a single, converged IP-based network. The largest example to date is British Telecom's 21st Century Network (BT21CN), which is being rolled out across Great Britain. The objective is to provide a cost-effective means to deliver and charge for "Internet style" applications and services.

To make this vision possible, the IP Multimedia Subsystem (IMS) has been devised. In many regards it can be considered as analogous to the Intelligent Network/Advanced Intelligent Network (IN/AIN) architecture that's found in the PSTN and cellular world today. It has only seen two significant application successes in the past two decades following its deployment: non-geographic numbers (which provide freephone/tollfree calling, for example), and pay as you go billing (which dramatically grew cellular market penetration).

I had a lot of concern regarding the anticipated success of IMS. The issue is of central concern to the telecommunications industry as a whole because it is regarded as the "telco savior" against the hard-to-defend trend toward zero cry regarding call prices. Besides, I believe that the issue is moot since the terms "call" and "telephony" are likely to be rendered so meaningless as to be dropped from common vocabulary in the next 20 years. Where then are the operator's historically wide profit margins?

Lee S. Dryburgh
Auto-Buddies: Connecting Relevant Strangers

O'Reilly Emerging Telephony Conference 2007

O'Reilly Emerging Telephony Conference
February 27 - March 1 2007
San Francisco Airport Marriott

The hope for IMS relies on the premium charges levied for subscriber mobility (courtesy of cellular technology), which are holding the castle walls until IMS is deployed and chargeable services are up and running. Just what these IMS-powered services are, nobody seems to know. This create the impression that IMS is not required, or at least is not fulfilling some unseen subscriber need.

As if a complete lack of proposed services wasn't bad enough, the narrow gate that IMS hopes to steer the telecommunications industry through suddenly became more narrow three years ago with the advent of Skype and other advanced Codec-based VoIP offerings. These offerings are often capable of rendering higher than PSTN-fidelity audio by utilizing the processing power of the endpoints, which make up for the unpredictable network characteristics of the public Internet. As James Enck said earlier this year, "Telcos have lost control of their core product." and "Voice is becoming a feature, not a service." The IMS vision predates the advent of quality over-the-top providers (OTTPs) like Skype, and would appear to assume that voice remains a service that can only be supplied at scale by telcos.

Increased customer-owned processing power, coupled with an ever faster worldwide homogeneous network (the Internet), is causing the world to reorganize along peer-to-peer modes of operation, and this is disrupting whole industries. I've never read economics, but it is quite clear that globalization will eventually break down every vertical market, leaving a horizontal market in its wake. For the most part, IMS represents the antithesis of this by clinging to a command-and-control intelligent core and vertical market.

As Thomas Friedman, winner of the Financial Times and Goldman Sachs Business Book of the Year award said in The World Is Flat: A Brief History of the Twenty-First Century:

"The world is moving from a place where value was created in vertical silos of command and control to a world where value is increasingly going to be created horizontally by how you connect and collaborate."

If all of this wasn't bad enough, it appears that IMS attempts to reinvigorate a business model that is based on scarcity. The telecommunications industry as we know it today is based on scarcity of processing and bandwidth. It is for this reason that customer premise equipment (CPE) has no microprocessor (in the case of the ordinary fixed handset), is coupled with an equally dumb access network (analog), and transports voice in an uncompressed narrowband format using a 1970s Codec (G.711). The model is analogous to the mainframe computer; telephone subscribers have dumb terminals and the user pays rent in the form of subscription to the provider of processing and bandwidth (the operator).

It takes no stretch of the imagination to consider that just as computing was democratized by the advent of the personal computer, telephony has embarked on a path of democratization with the advent of OTTPs. Just as the democratization of computing led to a whole new set of industries and the associated increases in wealth and significant economic and societal transformations, the democratization of telephony is likely to be another impressive technological tidal wave. For me, this is what O'Reilly's Emerging Telephony (ETel) conference is all about (Note to dear cynical reader: to date I've never received any money from O'Reilly, however unfortunate that is).

A business model based on scarcity makes no sense as we go into an era with an abundance of processing, bandwidth, and storage, all of which can increasingly be supplied by consumer powered peer-to-peer networks. or even through more traditional means. As a recent example of the latter, consider Amazon's Simple Storage Service (S3) and Elastic Compute Cloud (EC2) service. These services provide virtually unlimited storage, bandwidth, and processing power with no start up cost, no minimum fee, and a scalable pricing structure. It was, therefore, no surprise that some on the ETel organising committee pondered their use in telephony and set up a demo of scalable voice infrastructure based on S3 and EC2.

Casting an insidious shadow over the whole IMS vision are fears that the artificial scarcity (in terms of allotting fixed bandwidth streams regardless of overall network traffic) created with IMS control has evil intentions. There has been much speculation that IMS will be the tool that the telcos use to break network neutrality principles in their favor. More specifically, it is the quality of service (QoS) enforcement mechanisms of IMS that have been re-dubbed quality of suppression of competition.

The speculation goes that Internet Application Service Providers (ASPs), such as Skype or Google, will be forced to pay a special premium for the use of telco pipes, in correlation to application success in a fashion somewhat similar to how advertisers pay Google for visibility. The speculation further runs that the consumer end of the pipe is under an "extortion" attack too. If a consumer does not pay an access premium, then he may find (courtesy of IMS) all of his real-time UDP traffic is suddenly packet-shaped to have extra jitter, which makes rendering calls over the Internet worthless in terms of quality.

Network Neutrality is being fiercely debated and is rapidly growing into a political issue. In relation to IMS, it would appear to be that there is a consensus view since QoS techniques are not desired, therefore, the plan to roll them out under the hood of IMS must have an ulterior motive. QoS has already been given a public mocking and been debunked by academics. At the ACM SIGCOMM Revisiting IP QoS (RIPQOS) Workshop in 2003, Ben Teitelbaum and Stanislav Shalunov stated:

"QoS researchers have been too quick to assume that underlying congestion-control mechanisms translate obviously into marketable services…Neither customers nor ISPs need or want hard performance guarantee…Hard QoS without steep costs is unattainable."

Yet for all the IMS bashing, I also wish to re-evaluate my skeptical position. I hear your outcry, what could have caused this sea of change? One word: identity. Every time I research the value of future communications applications, the first stumbling block is the lack of identity on the Internet. This is why ETel has scheduled identity evangelist Kaliya Hamlin for a plenary speaking slot. If the Internet had identity built-in, we would not be seeing the incessant rise of spam, phishing, and other types of Internet fraud at such alarming rates.

The operators' largest asset could turn out to be their largely ignored, and not yet coined, "identity infrastructure." They know you are who you say you are, along with your location--either because you are attached to them by a copper umbilical cord or because they can cryptographically challenge your SIM card. Unlike Internet players, operators have a retail outlet presence that can check and validate your identity. IMS may be the key through which this identity value is unlocked courtesy of its identifiers and the Home Subscriber Store.

Whatever turns out to be the case, 80 leading operators so far have signed up to IMS interconnection agreements. One such operator, British Telecom is already underway with its BT21CN rollout, which by its estimates will ensure that the entire U.K. population is served not by the PSTN, but by an IMS controlled NGN by 2011.

Such dramatic changes in the telecommunications landscape cannot be ignored. I suggested to O'Reilly that we hold a gloves-off IMS debate at ETel to help extract the value opportunities and expose concerns about IMS. So, this debate will be held during one of the workshop timeslots. I plan to post more details surrounding the issue and proposed debate, and I invite you to also contribute. So stay tuned!

In the meantime, I will leave you with a figure I drew to stimulate thought at a cellular client of mine, and a poem of sorts by James Enck from Net Neutrality - just a symptom? James just happens to be listed as Bloomberg Markets Magazine(November 2006) champion communications stock picker:

Thy telco savior
Figure 1. Thy telco savior

"The world has changed a lot in a year
I'm not so concerned that telcos will be evil
Rather, I am concerned that they will be naïve and inept
And that the market overestimates the potential for this model to succeed
Most of all, I'm concerned that we may be distracting ourselves from the central issue:
Infrastructure"

Lee S. Dryburgh is a person-to-person communications technologist. He is both an engineering doctoral candidate at UCL (with sponsorship from Cisco) and a part-time SS7 (including Sigtran/Camel/Map) consulting engineer via his company 'SS7.net'. His research focus is the future of telephony and in particular enabling conversation between relevant strangers.


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