The cover story in the February 2002 issue on VoIP technology
was very informative. I am sure that it will be an eye-opener
for many Indian companies and they will subscribe to this
technology in its networks. I have a few queries.
1) If the technology is really so good why didn't the Indian
Government make it legal for telecom companies and organizations
to use this technology earlier?
2) How will voice packets move along with IP data packets?
3) Will VoIP be allowed only on VSNL's network? Will other
players like Bharti Telecom and Reliance carry VoIP traffic
Here are the replies to your queries.
1. The Indian Government was trying its best to
protect its interests in the state-run VSNL and BSNL; the
international and national long distance telecom players respectively.
Opening VoIP to enterprises and individuals would have affected
the revenues of these players. However, even now VoIP is allowed
in a closed loop, say over a Frame Relay.
2. With the use of VoIP technology, voice will convert to
IP data packets. These packets will move over a data network
in the same way any other data packet would move. The VoIP
packets will be routed and switched normally and will be reconstructed
as voice signals at the receiving end.
3. VoIP will be allowed over any private or public network.
Any telecom company or ISP can offer VoIP services to its
The Government still needs to clarify many issues pertaining
to VoIP, you will get a clearer picture only after April 1st,
when VoIP will be legalized.
The cover story on VoIP in the February 2002 issue is very
informative. I work in the capacity of Manager, Business Development
with an ISP in Gujarat. How can I calculate the cost of deploying
VOIP in my network? How much will I need to invest in hardware,
software, and other infrastructure? How will I calculate the
It is difficult to put a figure on the cost of deploying a
VoIP solution. Calculating the ROI on VoIP merits a whole
article in itself, something that we will feature in one of
our next issues.
Also, calculating ROI varies from enterprise to enterprise.
In case of an ISP, the parameters for calculating ROI will
A good idea is to seek advice from VoIP vendors like Cisco,
3Com, D-Link, etc. They will be very eager to help and you
can pick and choose a solution that suits you best. We are
forwarding this mail to the respective companies.
I am a scientist at DRDO, We have a 130 node LAN in Dehradun.
Our Intranet connects to Delhi and Bangalore through an ISDN
link. The Dehradun LAN also comprises of a main server, Web
server, a switch and a router.
I want to restrict particular LAN users in Dehradun from accessing
the Web server in Delhi. I know the IP address of the Web
server in Delhi. Do you think I might need a firewall?
You don't need a firewall because a firewall is meant for
keeping outsiders away from your internal network and not
so much to keep internal users away from another network.
Restricting users in Dehradun from accessing the Web server
in Delhi will require a little effort on the part of the systems
administrator in Delhi. He simply has to block IP addresses
of the LAN clients in Dehradun.
The functionality is present in the Web server OS which may
be Unix, Solaris, or NT.
I am a regular reader of your magazine. I have a few queries.
Do you need to register IP addresses for use in an organization?
If so, where do we have to register? Do we need to register
addresses of each terminal and router? And what is the main
function of NAT?
You can assign IP addresses at random within an isolated network
as long as each one is unique. However if you want to connect
your private network to the Internet you have to use registered
IP addresses to avoid duplicates. The InterNIC Registration
Service assigns Internet addresses from the following three
Class A - supports 16 million hosts on each of 127 networks
Class B - supports 65,000 hosts on each of 16,000 networks
Class C - supports 254 hosts on each of 2 million networks
You can visit the following links for more information about
assigning IP addresses.
NAT (Network Address Translation) is an IETF standard that
allows an organization to present itself to the Internet with
one address. NAT converts the address of each LAN node into
one IP address for the Internet and vice versa. It also serves
as a firewall by keeping individual IP addresses hidden from
the outside world.
device is it?
I liked your article on VoIP called 'VoIP: Packaged voice
and more' in the February 2002 issue. I am interested in exploring
VoIP options in my organization. In an architecture diagram
on page 26 you have named a network device as 'PWR'. What
is the device all about?
Dear Krishna Mohan,
Thank you for appreciating the article. I am sorry that the
diagram did not explain the meaning of the term 'PWR'. The
device is supposed to be a switch. Cisco has a LAN switch
of the same model name. The device should have been simply