Monday, February 10, 2003		Guest Speak

VoIP set to invade corporate sector
Rajesh Tuli

Rajesh Tuli,  CEO,  Coral Telecom

VOIP (Voice over Internet Protocol) has been legalised in India for limited applications but it will soon find acceptability as a prime mode of communication. This would make long distance telephony inexpensive, which means every one will like to change their switching platform to the ones that are IP compatible. So far IP telephony is possible by use of expensive IP telephones or by PC based solutions, which are expensive (minimum cost of a IP phone is around Rs. 2,000) and cannot replace the existing analog telephones that are extremely inexpensive (minimum of around Rs. 300) in comparison. Further in its present form IP telephony would require a separate network more like LAN using separate cabling. But for mass usage in large 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 will have to be intelligent enough to route certain set of calls (long distance calls) on the Internet protocol and another set of calls on regular circuits.

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 communication 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 will be far lesser than its transport over dedicated circuit switched channels because technology of IP provides for packetisation whereby a given bandwidth is shared for multiple channels of communication, while in 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 end customer premises equipments on these networks are extremely cost effective. What it means is that telephone or a device to convert our 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 equipments like analog telephones, fax 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 solution is to provide integrated solutions for circuit switching and data switching needs of corporate business houses using a single device. This can be done by having an inbuilt voice over IP cards for supporting long distance communication over the Internet. These VoIP cards have powerful DSPs for doing voice compression, echo cancellation, comfort noise generation and packetisation. Gateways and gatekeepers based on H.323 are inbuilt in these cards. The gatekeeper software does the routing of the 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 user in the switch from any part of the world through the Internet.

As a concept it is about developing the packetising capability into the switch itself so that it is used as a shared resource instead of providing this capability at customer end like in a SIP or H323 devices. It is this concept of shared resource development that will bring down the costs. VOIP card along with the simple telephone instrument can be compared to the SIP or H323 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, voice mail 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 also essentially shrink the telecom world much the same way as the Internet has brought people together. Once the switch is connected to the IP cloud then, you are connected and there is no significance of distance, much the same way as while downloading from the Internet.