AT&T Corp. last week threw its support behind the
global expansion of Internet-protocol telephony in a series of initiatives aimed at
fostering interoperability and cooperation among all players.
The move represents a major commitment to a long-term
transition from circuit-switched to packet telecommunications, officials said. But they
made it clear that they believe that voice over IP has a long way to go before it is ready
to supplant circuit-switched telecommunications.
Among AT&T's plans is the creation of a global
clearinghouse to assist ISPs (Internet-service providers) in establishing and fulfilling
terms of connection with each other. The clearinghouse is designed to create a
"commodities exchange" for ISPs to arrange termination of calls with other ISPs
"For IP telephony to take off, major players like
AT&T must show that they're willing to encourage the innovation and
interoperability that's required on a global scale," said Kathleen Early, vice
president for Internet services at AT&T. "We plan to take a leadership role in
promoting the evolution of ... Internet telephony."
AT&T is also inaugurating a special research lab
devoted to interoperability certification among IP-telephony vendors, and it is helping to
fund a research center at the University of California-Berkeley to foster the development
of innovations in the field, Early said.
In addition, AT&T will set up an in-house trial and
another multicity trial with an unnamed financial institution to begin testing the
delivery of IP-voice services in conjunction with virtual-private-network services. The
latter are widely seen as a major potential driver behind the penetration of IP telephony
in the business world.
By adding voice to the data stream in private-network
connections, business users will be able to engage in collaborative computing and
video-conferencing without having to establish separate voice-conferencing connections.
"In terms of the business world, we're going to
have to see a lot of functionality added to the value proposition in order to drive the
convergence of voice and data," said Mike Rich, vice president of value-added
services for AT&T.
AT&T's push comes as confusion has been mounting
in the IP-telephony world on issues associated with the intelligence that must be added to
the basic voice-over-IP capability that emerged on the Internet nearly three years ago.
While the capabilities have grown more sophisticated with
the addition of gatekeeper servers to manage arrays of gateways that interface IP-voice
traffic with the public-switched-telephone networks, the market has not settled on a way
to bring circuit-switched network-quality intelligence into the IP domain.
Instead, with ever more solutions coming into the
marketplace, there is growing uncertainty over whether the current standard widely used
for IP telephony -- H.323 -- will meet the IN (intelligent-network) requirements of the
IP-based global phone network of the future. AT&T officials made it clear that their
new interoperability initiative will focus on building success for H.323, rather than
going off in new directions.
"The principle challenge is achieving H.323
interoperability among vendors," Rich said, noting that this means working through
the issues with regard to "lowest-common-denominator" functionality first,
before getting to the higher levels of feature implementations.
As for any work on the IN question, Rich said, "Our
plan, in working with vendors and service providers, is to support the integration of PSTN
services -- like 800 number, 900 number and 411 directory -- and, over time, to promote
full international integration of SS7 [signaling system 7] capabilities and
Such gradual approaches to implementing IN in the IP domain
made sense to many players. But that strategy leaves unresolved the question of what
approaches should be taken to exploit the power of IP as a platform for creating
functionalities that go far beyond the traditional SS7 domain.
Such questions are much on the minds of Sprint Corp.'s
technicians as they plot their approaches to the local voice market.
"Part of what we need to evaluate is what makes the
most sense to replicate in the way of IN features inside [the IP network], versus
providing the same features on the life cycle of what's outside," said Mike
Gettles, lead engineer for advanced technology development at Sprint.
"From our perspective, we need carrier-quality service
support for communications within the IP network and for communications moving in and out
of the PSTN," he said.
Where to draw the line on IN is one of the key questions
that Gettles and his colleagues have left to answer as they resolve remaining design
issues for the first iteration of Sprint's Intelligent On-Demand Network (ION),
slated to go into commercial operations before year's end.
As Gettles noted, "There are plenty of service
capabilities that already exist in the PSTN environment that are useful in a packet
network, so we have to be careful about reinventing the wheel."
No matter how such issues are resolved, carriers of every
stripe can expect to be developing and delivering IN applications that largely parallel
the IN and SS7 capabilities in the PSTN for the next three to five years, said Scott
Wharton, senior marketing manager for service providers at VocalTec Communications Ltd.
After that, he said, the momentum behind feature
provisioning and network-functionality control within the IP domain will outstrip
traditional IN to the point of decoupling the two.
"As more intelligence is built into the gatekeeper,
[IP-telephony] providers will be able to go beyond the limitations of the current system,
but that will take a while," Wharton said.
"We'll see unified messaging and multimedia
capabilities, combined with open APIs [application program interfaces], that represent
something much more than can be done today in the PSTN, and not just a better
version," he added.
Not only is the long-range solution a matter of contention
in this regard, but there's no readily agreed-on means of interfacing with the legacy
SS7 network. While VocalTec is already implementing features that it expects to be part of
version 3 of H.323, it will take a while for issues to be worked out before the current
version 2 -- which is only now going into commercial release -- is superseded at the
standards level, Wharton noted.
Consequently, VocalTec and everyone else seeking to respond
to early carrier demand for IN solutions will be pushing the envelope with proprietary
solutions that may or may not end up being standardized.