Monday, May 27, 2002		Article

One PC, two modems & abundant speed
Vipul Verma

SPEED is the key to the success in the virtual world. No matter how fast and advanced system you are working on, unless it also races up on the Internet it's of no use. Talking in terms of India, good Internet connectivity and higher bandwidth is still a wannabe and in a majority of cases, the surfer really suffers due to limited bandwidth of the ISP, besides poor connectivity and telephone line conditions.

Practically, there is a lot more to be done as far as the bandwidth is concerned. But why wait for things to happen when you can create the world of faster Internet and better bandwidth.

Welcome to the world of modem doubling. Modem doubling in its most simple sense means combining two modems in one computer using two telephone lines. It is an inexpensive way for a user who wants a fast Internet connection but can only connect with an analog telephone line, to use two 56 KBPS modems to double the bandwidth.

It is not as simple as is said. If you try two modems on one computer and connect both to the Internet and start browsing, then you will find that the data transfer takes place with one modem at a time only and the other modem remains quite though it may happen that the switching of data packets is faster between two modems and may give you the feeling that both modems are working at the same time. But actually only one modem works at a time and the second connection is almost waste.

You may then wonder how the modem doubling is good? Modem doubling does not simply mean connecting two modems to the Internet simultaneously. It is actually far more than that as it is made possible by the use of two technologies:

1) Modem bonding

2) Modem teaming

Modem bonding is the most basic and also the inherent feature. It is supported by some ISPs also. Under the modem bonding, the Multilink Protocol Plus (MP+) is utilised to combine the bandwidth of two modems running two Internet connections on two telephone lines. Data packets are "inverse-multiplexed" through the two modems meaning that each of the modems receive half of the data packets as they are sent over the Internet and then are recombined.

An advantage of modem bonding is that if either the modems gets disconnected for some reason, the other modem will take over so that the connection isn't lost. In case of modem bonding, the software at both ends of the modem- to-modem connection enables the paired modems to work like a single channel. There are basically two methods of modem bonding:

1) EQL or it is also known as serial line load balancing. However, this is not common in practice and not many ISPs support it.

2) The second type of modem bonding is known as Multilinking. Multilinking is the most common type of modem bonding and is a common feature of Windows operating system. You can find the multilinking feature from Windows '98 SE onwards. However, not many ISPs provide multilinking facility in India.

In case you are sending the data through multilinking, then the first packet goes out on modem1 while the second packet is going out on modem2. Then the third packet follows the first packet on modem1. The forth packet goes on modem2. And this goes on and on. This is how the data is combined on two modems in multilinking. However, you must confirm it from your ISP, whether multilinking support is available with them. If it is available then all you need to do is configure your modem properties, which is a simple exercise, as you have to give details of the second modem connection.

If you are not lucky enough to employ multilinking then you need not lose heart, as there is another option available. This is called modem teaming. In case of modem teaming you are actually not dependent on the ISP and its support.

Any computer and Internet user can employ this technique to almost double the bandwidth. Under this technology, the modems work as separate connections and take advantage of the "smart download" capability that most HTTP and FTP servers use. However, using modem teaming you would need some special software to combine the bandwidth of two modem. Some of the good software available is Modem teamer and Midpoint companion available at www.midpoint.com and Sygate Office Network is also available at http://soho.sygate.com/products/access_ov.htm.

Both these products are good and offer good results for the end users. You can try this software for a limited period by downloading from their respective sites and can see the results in your specific case. Modem teaming is now successful and has come of age. Modem teaming has its own advantages and disadvantages. The biggest advantage of modem teaming is that you can combine as many analog modems you want and can boost the bandwidth of your Internet connection considerably.

However, the biggest limitations attached to modem teaming is that it is not flexible if one modem should disconnect nor is it useful when downloading streaming multimedia or conducting continuous sessions such as Telnet or PCAnywhere.

All said and done, modem teaming is still a great experience and a big performance booster. Modem teaming could do wonders in case you feel that you have a stable Internet connection but the speed is much slower.