ADSL Technology for Faster Internet Speeds
Many of you may know that BSNL Data One services are based on ADSL technology. ADSL is the short form of Asymmetric Digital Subscriber Line. This technology allows you to have two way traffic at different speeds. Usually the high traffic direction is used for downloads and low traffic direction is used for uploads.

The greatest advantage of ADSL technology is the ability to use your telephone & internet simultaneously. Thanks to the technology, where un-used frequencies are used for data transfer. Voice and Data are split using an ADSL splitter and is fed to telephone and modem respectively.
Advantages of ADSL
1. You can use telephone & modem simultaneously. ( Thanks to ADSL splitter )
2. Higher data rate; ADSL system can be used for upto 26mbps maximum wherever possible.
3. Uses normal telephone lines. Hence if you have wired phone, its quite easy to start using ADSL.
4. Always on connection.
5. ADSL modems are cheap and everyone can afford it.
ADSL Disadvantages
1. Your modem must be less than 5kms from exchange.
2. Small problems in telephone line can cause problem to ADSL connection.
3. Download rate will be greater than upload rate.
4. Upload rate is very much slower than download rate.
5. May experience slow bandwidth during telephone usage. (depends on signal strength and distance)
Types of ADSL
ADSL
Allows bandwidth up to 10mbps download.
ADSL 2
This next generation technology allows higher bandwidth up to 12mbps using single pair of copperwire and 24mbps for 2 pairs of copperwire bonded together.
ADSL 2+
This version allows bandwidth upto 26mbps with in 1KM from exchange and ADSL like speeds upto 2KM-5KM.
ReADSL 2
This generation ADSL solves some of the distance problem and allows comparably higher bandwidths at long distance.
Check out the following figure to know more about distance / bandwidth performance of different ADSL technologies.

You will be surprised to know that Japan & South Korea have better technology than this and their average bandwidth is 50/60Mbps.
Lets go Japan!




Xrio December 19th
Virgin has just gone 50Mbps in the UK and Be is now providing 46Mbps connections using Bonded ADSL connections – the issue in the UK is the really rubbish telecoms infrastructure
It all sounds good however even Virgins dedicated high-bandwidth services fail to improve upload speed which bonding would do and in any case most bonding providers limit you to multiple connections from one ISP which means your Bonded connection, like leased lines is still subject to being a single point of failure.
In my research I have discovered services like Broadbond which bonds multiple, mixed connection types including 3G, 21CN and WIMAX from multiple ISP’s which would theoretically overcome the loss of physical connection, issues with routing centres and other issues associated with relying on connections from a single ISP.
2009 will definitely be the year of Bonded ADSL!
Tuning December 31st
Hi Xiro,
What is the difference between “bonding” and load balancing ?
AFAIK, both combines bandwidth to single interface.
mush_pilot December 29th
bonding technology provides the ability to accelerate a session over multiple WAN connections, so the speed for a single session will be the sum of all the WAN connections. Load-balancers on the other hand will only funnel a session over just one WAN connection and therefore your speed will be limited to that one line that session ends up on.
Tuning December 29th
Thanks Mush,
That is great to know.
- T
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