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Businesses can deploy new technologies
like VoIP and yet protect their investments in legacy
systems, using integrated solutions. by Rajesh Tuli
Convergence was the buzzword
in the high-end enterprise market. Even as technologies
became available across the world, there remained a
wide gap between the availability of this converged
technology and its actual application, because of the
lack of broadband access in the country. So a majority
of PBXs and DLCs (Digital Loop Carriers) remained pure
voice switches.
Indian consumers have acknowledged
the rapidly changing nature of technology and also the
advantages each technology presents. With easier availability
of broadband connectivity, the consumer expects premium
data access services. But there is still a limitation
on distance for transmission of high-bandwidth data
over copper wire. So there was a need for a new generation
of broadband DLCs, that would act as street cabinets
to provide connectivity to various subscribers in the
neighborhood. DLC is like a concentrator of telephony
traffic. The distance limitation of carrying high-speed
data on copper will see more systems acting as neighborhood
nodes, or streets cabinets rather than central switches.
CHALLENGE
The challenge lies in effectively implementing a network
that optimizes a variety of signals from voice, data
and video services. The solution is to provide for adequate
protection for existing investments in legacy systems
while providing for seamless integration with high-speed
data. That would enable existing networks to provide
multi-service access platforms without congesting existing
expensive networks deployed by telecom companies for
toll quality voice services.
Hence these street cabinets
will become even more intelligent and would provide
a bouquet of voice and data services on copper wire
to consumers. These street cabinets would concentrate
voice traffic and divert it to main exchanges over fat
voice pipes on copper. Street cabinets would also concentrate
data traffic and intelligently separate it from the
voice traffic, and may directly send it to the IP cloud,
possibly via the main exchange.
Let's evaluate the various
factors involved and the direction that the new generation
switches are likely to take in the VoIP space.
VoIP: ISSUES AND CONCERNS
VoIP (Voice over Internet Protocol) has been legalized
in India for limited applications, but it would soon
find acceptability as a prime mode of communication.
This would make long distance telephony inexpensive,
which means many are likely to make their switching
platforms IP compatible. So far IP telephony is possible
using expensive IP phones (Rs 2,000 onwards) or through
PC based solutions. In comparison, regular analog phones
are extremely inexpensive, so it seems as if IP phones
will never replace analog phones.
In its present form IP telephony
would require a separate network akin to LAN networks,
using separate cabling. But for large-scale usage in
corporate environments there would be a need to integrate
these two forms of telephony so that a corporate executive
has only one telephone on his table, and the switch
would have to be intelligent enough to route a certain
set of calls (long distance calls) on IP, and another
set of calls on regular circuits. Similarly, all incoming
calls, irrespective of the medium of transport, should
arrive at the usual telephone instrument.
THE RIGHT BALANCE
Presently data networks and circuit-switched voice networks
are essentially independent units with limited interconnect.
There is a great need to develop cost effective systems
that would carry voice and data over the same existing
set of copper cables—at speeds that would meet
the requirements of data and voice communication within
a corporate institution. The need for a transparent
intermix is all the more evident as the transport cost
of voice over data channels would be far lesser than
its transport over dedicated circuit switched channels.
This is because IP technology provides for packetization,
whereby a given bandwidth is shared for multiple channels
of communication. In a circuit-switched environment
each communication channel requires dedicated bandwidth.
Despite the transport cost,
the circuit-switched environment cannot be ignored because
of the vast availability of this legacy telecom network,
and also because the customer premises equipment on
these networks are extremely cost effective. The telephone
or device to convert the voice signal into a transportable
form on circuit switches are much cheaper than their
generic substitutes for doing the same on IP or data
channels. Circuit switched networks have further advantages
as they still offer supremacy in quality of service
and also continuity of the same telephone numbering
plans.
So there is a great need to
provide total integration of the two networks so as
to take advantage of cheaper transport on one side and
of cost-effective end customer equipment like analog
telephones, faxes and answering machines on the other
hand. This should be possible on the existing set of
telephone wires with transparent interconnect with the
circuit switched world.
THE WAY OUT
The solution to address the circuit switching and data
switching needs of corporate business houses is to provide
integrated solutions using a single device. This can
be done using built-in VoIP cards for supporting long
distance communication over Internet. These VoIP cards
have powerful DSPs for doing voice compression, echo
cancellation, comfort noise generation and packetization.
Gateways and gatekeepers based on H.323 are built into
these cards. The gatekeeper software handles the routing
of voice packets to various destinations through the
Internet. Various applications like least cost routing,
private networking, etc can be implemented using these
VoIP cards. Using these VoIP cards, it has become possible
to reach any extension in the switch, from any part
of the world, through the Internet.
As a concept it is about developing
the packetizing capability into the switch itself, so
that it is used as a shared resource instead of providing
this capability at the customer end, as in SIP or H.323
devices. It is this concept of shared resource development
that will bring down the costs. The VoIP card along
with the simple telephone instrument can be compared
to the SIP or H.323 device.
The switch will essentially
have the router capability, whereby it would allocate
IP addresses to each analog and digital extension user
to be able to integrate data switching and dynamic bandwidth
allocation to the user extensions. Such router capabilities
providing independent IDs can have additional advantages
like setting up a pool of extensions for receiving fax,
voicemail or modem calls. Router capabilities would
further allow telephone and data calls to be routed
by name as well.
Such voice and data servers would essentially shrink
the telecom world much the same way as Internet has
brought people together. Once the switch is connected
to the IP cloud there is no significance of distance.
CONCLUSION
Most businesses would prefer to use VoIP as the preferred
mode of communication for long distance telephony. This
is the only integrated solution that does not require
a separate data network for VoIP calls and would allow
usage of existing low cost analog telephony equipment
for transparently receiving or making calls. Alternate
solutions are expensive requiring separate data networks
using computers with multimedia kits or IP phones for
voice communication, which makes the solution not only
expensive but also difficult to operate as the user
will have to make and receive calls from the circuit-switched
world on separate telephones. The solution will be intelligent
enough to automatically route certain calls over IP
networks and others over circuit switched channels.
It will use the same telephone instrument for accessing
both channels hence eliminating the need for separate
networks.
The writer is CEO, Coral Telecom.
He can be reached at rajeshtuli@coraltele.com
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