|A Look Into
The Future By Someone Who Is Always Wrong
BY AMI AMIR
I was involved in VoIP before I even knew that it existed. So I should know what
I am talking about. Right? Wrong.
In spite of the fact that for two years our programmers were using Linux on their PCs,
I never took the second most popular PC operating system seriously. We (RADVision) started
offering a Linux version of our H.323 toolkit only this year. To paraphrase Julia Roberts
in Pretty Woman: Big Mistake. So, probably a large part of what I am going to
claim for the future is wrong.
THE VoIP STANDARDS WAR THAT WAS
A few months ago, there was a raging electronic war going on between two major camps. The
Internet Engineering Task Force (IETF) camp was
represented by Telcordia, Level 3, Cisco, and
some teams within Nortel Networks. The
International Telecommunication Union (ITU) camp was
represented by Ascend (now part of Lucent), Lucent, Siemens,
other Nortel Networks teams, Intel, and Microsoft. E-mails were rampant and emotions ran high.
Of late, there has been a very positive change, and the religious wars are giving way
First consensus Transport. There is no argument that
the IETFs work on SIGTRAN, as a transport protocol of SS7 and ISDN signaling over
IP, will be used by all. Likewise, the IETFs Real-Time Protocol (RTP) is used by all
as the media transport protocol.
Second consensus Gateway Control. The control of
decomposed gateways is covered by the MEGACO work of the IETF and the H.GCP ITU draft.
Both works are headed for a merger, replacing Simple Gateway Control Protocol (SGCP),
Media Gateway Control Protocol (MGCP), Internet Protocol Device Control (IPDC), and Media
Device Control Protocol (MDCP) (did I forget anyone?).
Third consensus Signaling Gateways. The ITU H.246
gateway standard will include issues formerly covered by IETF work on SS7. It will be the
only standard for signaling gateways.
No Consensus (yet) Endpoint Signaling. The only
big open item is SIP vs. H.225.0 (the H.323 signaling standard) as the
endpoint call signaling protocol. My guess is that H.225.0 shall win. I think that at the
end of the day, it does not matter which will win. Even if two standards remain, the
situation would be much better off than in many other industries.
THE REAL PROBLEMS?
Quality of Service (QoS). QoS does not exist. There is not a single QoS
end-to-end solution that actually works and provides predictable, consistent performance.
RSVP, DiffServ, and 802.1p will not solve the problem. We have a long way to go yet, and
customers will be very reluctant to pay for inconsistent and unreliable service.
Scalability. To date, no one has deployed a sufficiently
large network that supports millions of calls per minute. So how can we be sure that the
solutions actually scale? We just hope it all works.
Security. Solving the security issues is tough. There needs
to be network-level security to protect against hackers that can bring down an entire
network. Witness the Melissa and Chernobyl viruses. There needs to be control and
management level security that will prevent outside interference in network
configurations, manipulation of user data, erasure of billing information, and toll fraud.
Privacy. VoIP privacy is a joke. The current implementations
are wide open. Once you decide to use VoIP, you need to assume that everyone who has
access to your network can participate in your call. And how do you actually know who has
access? A single rogue PC with remote desktop sharing software could open your network to
the whole world.
OSS. Operations, Services, and Support systems are not yet in
place. Out of the total cost of operations of regular telephone networks, only a small
percentage goes into switching and routing calls. A much larger part of the money is being
spent on managing facilities, billing, and provisioning. An economically viable VoIP
network needs to reduce the costs of OSS. There is no solution in sight.
THINGS TO CONSIDER
There are two big debates that really drive the work we all do now. The first
involves the smart network/dumb terminal vs. the smart terminal/dumb network. The old
phone system was based on a dumb terminal (your phone) and a network that tried, albeit
not very successfully, to be smart. H.323 evolved around the concept that since telephone
networks are dumb, lets build a smart terminal. SIP evolved around the concept that
since we can build smart IP networks, let the endpoint be dumb (and hence cheaper to
My guess is that we will end up with the best of both worlds, a smart terminal
(if my in-laws call, I am out) that connects to a smart network (I need
to talk to Joe, please find him for me).
The second debate is the large homogeneous networks versus the small service providers.
AT&T, Level 3, and Qwest adopt a model of a
single seamless VoIP network (obviously owned by them) that is centrally controlled via
hierarchical mechanisms. MGCP assumes a centralized control mechanism of each call via a
call agent. That is why they promote MGCP. The concept is centralized. A single call agent
owns the call.
Another model exists, of a flat, non-hierarchical network served by multiple providers
and multiple gatekeepers. This is the underlying model of H.323, which assumed from Day 1
that the calling party and the called party are registered with different gatekeepers.
Which is right? The answer is obvious. Both solutions shall exist. The architecture
that fits all models is a distributed network server architecture that allows one provider
to provide the pipes, and another vendor to provide the services an architecture
where the transport is disassociated from the control and the services. We need to adopt a
concept similar to SS7 in PSTN an architecture that really allows each provider to
customize the network and provide unique services.
SO WHATS GOING TO HAPPEN?
Toll bypass is dead. It is not cheaper to make calls on IP compared to regular
phone networks. Now that regulatory barriers are down, and due to the glut in fiber-optic
cable (thanks to those brilliant people who invented WDM), the cost of making
long-distance phone calls has plummeted all over the industrial world. The IP-based toll
bypass business, as a means to save on long-haul phone calls, is dead.
This does NOT mean that VoIP is dead. On the contrary, the VoIP industry is just
starting to evolve. The opportunities are unbelievable. It is just a matter of time before
VoIP shall reign. The MEGACO and H.GCP standards are merging. H.323 is definitely here to
stay. The IETF carries the day as far as transport (RTP and SIGTRAN). The future of SIP is
not yet really clear, but I expect to see SIP-based terminals deployed.
Initially, VoIP will be used mostly inside organizations, offering a way to create a
global PBX for the enterprise. Internet call waiting and Internet commerce
will become major forces driving deployment of VoIP gateways. Cable modems will support
VoIP (using SIP), and will provide a way for CLECs to bypass the LECs without having to
install copper wires.
Integration between the mobile/wireless network and the IP network SHOULD happen, but
God knows when. Who stands to gain and who will lose? Everybody stands to gain! No one is
the loser in this new game. There are huge opportunities for equipment vendors, systems
integrators, and new and incumbent service providers.
Finally, all of us, as users of the new network, will be the biggest winners of all.
Ami Amir is CEO of RADVision, Inc. RADVision develops industry standard
building blocks needed for supporting voice and video calls on packet networks
like the Internet. RADVision core technology spans a broad range of product environments,
from chipsets and hand-held devices through carrier class gateways and switches. For more
information, visit the companys Web site at www.radvision.com.