At the present time, there are three methods of connectivity available in India.
These are:
a. Connectivity through wireless transmission:
b. Connectivity through telephone landlines:
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Connectivity through telephones includes three recommended methods.
These are:
Connectivity through dial-up lines; connectivity through leased lines and connectivity using ISDN (Integrated Services Digital Network).
c. Connectivity through VSAT:
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Connectivity’ through VSAT has two recommended methods and in fact each of these recommended methods should probably merit consideration as a separate method of connectivity.
These are: connectivity using Time Division Multiplexing or Time Division Multiple Access (TDM/TDMA) and connectivity using Single Channel Per Carrier (SCPC).
This again consists of two possible methods:
Demand Assigned Multiple Access (DAMA) and Permanently Assigned Multiple Access (PAMA).
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We have to choose between these options for our connectivity between the headquarters and the branches. We shall discuss the various considerations involved in each form of connectivity below. Let us first discuss connectivity provided using wireless transmission.
In using wireless transmission, the reliability seems to be fairly good up to a point. The problem is that the point is reached fairly quickly. Wireless transmission can be used effectively over distances of up to fifty kilometers. Beyond that, the signal tends to fade quite rapidly.
Therefore, for distances of more than fifty kilometers, a booster or repeater station has to be used. The use of such a repeater station tends to increase the cost substantially. In fact, the use of one repeater or booster station tends to almost double the original cost. In general, the cost over a distance of fifty kilometers or less for data transmission rates of 64 kbps is approximately Rs. 10 lakhs.
The basic advantage is that apart from the cost of government licenses and the cost of maintenance (which reportedly is not high), the operational cost is negligible. However, there may be other limitations. Suppose the organisation concerned starts up with a 64-kbps wireless connectivity.
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Later on, they wish to start video conferencing between the headquarters and the branches. Typically, they would need at least 128-kbps connectivity. For this, they would have to change most of their equipment. This could run into heavy costs. In other words, there are limitations in future expansion.
Bechtel Corporation is an example of a company using such connectivity. There are several companies in India that deal with this form of connectivity. These include companies such as RAMCO or UNICORP who offer such services.
Next, let us look at landlines or telephones. Connectivity is typically provided by using leased lines, though dial-up lines are also available. Reliability may be a problem here. Leased lines are reportedly not very reliable in terms of availability. A typical reaction from one user was “from the amount of down time in a leased line, a dial-up line may be better”.
Therefore, if reliability is a very important consideration, the planner might like to avoid this form of connectivity.
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The problem in case of using dial-up lines is the fact that typically data transmission rates of 9600 bps only are available. Added to this is the problem in leased lines that unless the two points are very centrally located, there is the problem of the “last mile” (that is, the connection between the exchange and the user at each end point).
The authorities do not operate in a competitive environment and therefore, tend to neglect users. The other limitation is that of data transmission rate. If the user wishes to suddenly switch to a higher transmission rate, he can do so, but at a price. The next higher data transmission rate offered by MTNL or DOT (as the case may be) is 2 Mbps, which may be too much for the user.
However, the single biggest advantage offered in this form of connectivity is that in terms of cost it is much lower than that offered by other forms of connectivity.
Now let us look at the costs involved in providing connectivity through leased telephone lines. We are not going to calculate the cost for 9600 bps lines, because this data transfer rate is too trivial for serious use in a wide area network. We will, however, consider the cost involved in a 64-kbps leased line.
The cost is calculated on the basis of the rates announced by MTNL/DOT. The rate per kilometer varies between Rs. 450 per km and Rs. 900 per km per year, subject to Rs. 11.25 lakhs for a maximum of 1500 kilometers. Based on this, the cost of using a 64-kbps line over a distance of 1500 km is Rs. 11.25 lakhs per year. For using a 2-Mbps leased line, the rate is much higher.
The rate per kilometer for 2-mbps leased lines varies between Rs. 2150 per kilometer and Rs. 4,300 per year, subject to a maximum of Rs. 53.75 lakhs for 1500 kilometers.
The cost of using a 64-kbps line is, however, very reasonable and compares very favorably with the cost of data communications using any other means, particularly if one considers the fact that there is no other operational cost. The major problem in using any facility from MTNL is the fear of getting very poor or no service from them.
Next consider Integrated Systems Digital Networks (ISDN). Integrated Systems Digital Networks are, by design, highly reliable and offer high bandwidths.
However, there is a limitation that at present they are available only in 18 cities in India—the four metros and fourteen other important cities, such as Ranchi, Guwahati, Bangalore, Nagpur, Kanpur, etc. This poses a limitation on the extent to which ISDN connectivity can be utilised.
Further, MTNL has recently announced a reduction in the rates for both, 64-kbps leased lines and 2-Mbps leased lines. This means that the new rates are proposed to be reduced by a figure varying from 92% to 67%—a very substantial reduction.
A look at the rates being offered for ISDN facilities may provide a clue to the reasons for this proposed reduction in rates. We shall keep this discussion in abeyance until after the discussion on ISDN facilities being offered on landlines by MTNL/DOT.
ISDN or Integrated Systems Digital Network is used either as Broadband ISDN or as Narrowband ISDN. There are many kinds of telephone networks, many of which are used by the telephones department or in the case of the US by different telephone companies. There is the old circuit switched network, Switched Multimegabit Data Service (SMDS), DQDB and SSN networks.
All or some of these networks may be in use by the telephone department. In addition, there may be television networks and other specialised networks that are not being controlled by the telephone departments (but they would dearly like to control). It would be ideal if all these networks were integrated into one single network. ISDN is an attempt to do this.
Such a network obviously has to be high speed. Admittedly, integrating all these networks in India is not going to be easy, but this seems to be the ideal to aim for. The underlying technology for broadband ISDN services is Asynchronous Transfer Mode (ATM) Technology. Incidentally, Automatic Teller Machines or ATMs, as they are generally called, may be one of the applications to which ISDN services may be put.
ATM machines may use ATM technology to communicate with the parent bank, to service its customer. In ATM technology, the basic idea is to transmit all data in small fixed packets called cells. Each cell is 53 bytes long—48 data bytes and 5 header bytes. The readers may point out this is the same as in a DQDB cell.
The difference is that in a DQDB cell, the payload size is limited to precisely 44 bits (unlike exactly 48 bits in an ATM cell). Sometimes an ATM cell is also referred to as cell relay (as opposed to the earlier frame relay). It also uses a digital bit pipe, a conceptual pipe between the user and the carrier; the type of data is irrelevant in this pipe.
Also, the flow of data is bidirectional in this bit pipe. However, we shall concern ourselves only with the abilities of ISDN services to provide data connectivity for wide-area networks. Usually, this means using broadband ISDN services.
ISDN facilities are now available in India, but there are some limitations. At the moment, only narrowband ISDN services are available in India, between the four metropolitan cities and ten other cities, such as Hyderabad, Luck-now, etc.
But ISDN services, particularly broadband ISDN services, do not have any technical limitations for use in wide area networks. However, for a high-quality but narrowband 2-Mbps ISDN connectivity, the charges are Rs. 2,000 per km at a minimum. Thus the cost of setting up a network between 2 cities, 1500 kilometers apart, is about Rs. 30 lakhs.
But with the proposed cost of 64-kbps and 2-Mbps leased lines being sharply reduced, the cost of ISDN lines is no longer an issue because the cost of leased lines is very comparable even for 2-Mbps leased lines.
Since the service provider is MTNL/DOT in both cases, the quality of service is not a factor for selection if the choice is between these two methods of connectivity only. If these two factors have to be considered and the best method has to be selected, the type of service could be a consideration.
Very Small Aperture Terminals are invariably referred to by the acronym—VSAT. We shall also refer to it by its accepted acronym. VSAT facilities are being offered by several companies in the country— Hughes Escort, HFCL, TELSTRA, WIPRO-BT, HCL are the prominent ones among them.
As we shall see, the cost of a normal leased line from VSNL/DOT is considerably less than that of the cost of communications using VSAT, except over very long distances.
Nevertheless, VSNL’s “government department” attitude has made many users conscious of the fact that by using VSAT facilities, they have their resources largely under their own control, unlike in the case of leased lines hired from MTNL/DOT.
Admittedly, the user has to pay a price for this independence. But seeing the performance of leased lines, most users feel that the use of VSAT is worthwhile. The poor performance of MTNL/DOT is the main reason for the growth of companies offering VSAT facilities.
VSAT facilities are being offered in two forms. These are Time Division Multiplexing/Time Division Multiple Access (TDM/TDMA) and Single Channel Per Carrier (SCPC). SCPC can consist of PAMA or Permanently Assigned Multiple Access (which is utilised for very special reasons) and DAMA (Demand Assigned Multiple Access).
Obviously, the name DAMA is a misnomer considering the fact that a single channel per carrier is used; however, the acronym persists. Historically, TDM/TDMA preceded DAMA and it took a long time for government to give its clearance for the use of DAMA. Naturally, because of its historical precedence, TDM/TDMA suffers from some problems when compared to DAMA.
We can compare the advantages of each of the two methods of data transmission.
Satellite transmission is based on the use of geosynchronous satellites (the Iridium project notwithstanding), whose use avoids the complex shifting of antennae to keep track of the satellite shifting from its position in relation to the ground station.
A geostationary satellite also avoids the problem of being out of communication with its earth station for pan of the time. In Time Division Multiplexing, because each demand for communication must be routed through the main earth station, there are problems of time lag.
Although this is small (typically of the order of 540 milliseconds, compared to about 4 microseconds for point-to-point landlines), it nevertheless introduces an undesirable delay. Consequently, if only data communications is required, no severe problems should exist. But the operational cost tends to be high, because the users’ charges depend on the permanent bandwidth allocated to him/her.
Naturally, in normal regular use, the same bandwidth is not required all the time. However, since a permanent bandwidth has to be allocated to the user, as a precautionary measure the user tries to book and pay for his/her maximum bandwidth requirement. On the other hand, in DAMA, the bandwidth required is available on demand.
Consequently, the usage charges tend to be lower. But the installation costs are exactly the opposite. While in case of TDM/TDMA, the installation costs will generally be around Rs. 6 lakhs per earth station (including the cost of the necessary routers and bridges), in case of DAMA, the installation cost per site is of the order of Rs. 13 lakhs per site, that is more than twice that of TDM/TDMA.
In the cost of usage, however, DAMA scores substantially over TDM/TDMA. The operational cost of the use of TDM/TDMA works out to between five to twenty times than that of the use of DAMA.
Further, in case of TDM/TDMA, the bandwidth available is of the order of 64 kbps. For the use of higher bandwidths, the operational costs go up almost exponentially. For activities, such as video conferencing, 64 kbps is usually not enough. In case of DAMA, the available bandwidth can go up to as much as 8 mbps. Furthermore, integration of voice and data channels is not very good in case of TDM/TDMA.
The one big advantage that TDM/TDMA usually has, however, is the quality of voice transmission. It is reputed to be far better in this respect than SCPC. Consequently, only in very special cases, the information technology strategic planner will select the use of TDM/TDMA. Normally, the reduced operational cost will justify the selection of a VSAT facility using SCPC technology rather than TDM/TDMA.
The Information Technology strategic analyst must, however, do an analysis based on the kind of expected usage and the value of expected usage, adjusting the value of money over a period of time and find out the number of years over which the cost of TDM/TDMA and DAMA become equal.
If this period is of the order of say five years, the economics may not necessarily favour DAMA. Admittedly, we have not gone into very deep technical details of the various methods of data communications for the purpose of a wide-area network.
Next, let us look at ISDN facilities available in India and try to arrive at a recommendation for the example organisation, which we have selected. Naturally, we will have to consider all the necessary facts about all the methods of data communications available in India, before a decision can be recommended.
The discussions on connectivity can now be summarised and we can look for the recommendations for the sample organisation, which has been selected. Let us look at the requirements of the organisation under discussion. This organisation has requirements to connect, say, twenty branch offices with its headquarters.
The data transfer must be secure, as well as quick. Also, some branch offices need to be connected to the headquarters with the capability to conduct video conferencing.
The choices available are:
Wireless communications, VSAT connectivity—TDM/TDMA and DAMA, leased telephone lines—64-kbps and 2-mbps, and dedicated ISDN telephone lines.
The considerations before you are:
1. Quality
2. Availability and speed of the facility
3. Cost involved—one-time cost as well as the cost of operating
4. Maintenance of the system
5. Safety and security
6. Reliability and
7. Availability
and finally other considerations, such as the value chain of the organisation as well as that of the service provider. However, one suggestion may be added.
In addition to the information required, the reader may be reminded of Machiavelli’s admonition:
“… I have thought it proper to represent things as they are rather than as they are imagined. Many have dreamed up republics and principalities which have never in truth been known to exist; the gulf between how one should live and how one does live is so wide that a man who neglects what is actually done for what should be done learns the way of self-destruction rather than self-preservation.”
All the evidence is now in. Consider it, as also Machiavelli’s warning, and deliver your verdict.
In the above discussions, the situation concerning connectivity of wide-area networks in India have been analysed.
Communications and networking are two of the most important areas about which one must have complete information before any strategic decision regarding the deployment of suitable Information Technology equipment can be taken. The relevant facts about the communication facilities in India have been presented above.
Fortunately, in the case of networking, there is likely to be very little that the government’s bureaucracy can interfere in. Therefore, the state of the art present in the world today can be utilised in the network to be constructed (if such a network is advised by the Information Technology strategist).
TISCO, therefore, could take a decision on the modes of connectivity between its works, its marketing head office and its branches by taking into consideration the issues, that is, reliability, volume and frequency of data, scope for future expansion and limitations of each method of data communications, apart from the cost.
It must be remembered, however, that the form of data communication between the head office and each branch office may be independent of the form of data communication between the head office and any other branch.
Thus, it is possible to have more than one form of data communication in the entire wide area network connecting TISCO’s works in Jamshedpur, its marketing head office in Kolkata and its branches spread throughout the country. The above analysis of TISCO’s requirements has been treated as an example and independent of its overall Information Technology strategy.