 MTNL Mumbai has probably become the first Broadband Service Provider in India to offer “Line Bonding Internet Service“.
MTNL Mumbai has probably become the first Broadband Service Provider in India to offer “Line Bonding Internet Service“. 
What is Line Bonding ?
Line bonding is a process in which two broadband connections are taken and made them to work as one, so the Broadband Speed is doubled at the users end. For Example, if a user is receiving 4 Mbps download speed, with line bonding they can expect to receive 8 Mbpswhich is similar to fibre / FTTH broadband .
Why is Line Bonding Done ?
Some users are bandwidth guzzlers and want to merge two separate ADSL lines to get double the speed. They started doing so using a Router like  ZyXel ADSL2+ Bonded 4-port Router which can support ADSL2+ connections. Thus to satiate such users, MTNL itself is doing so at the Exchange end (DSLAM).
Details of MTNl 8 Mbps Triband DSL Plan with Line Bonding
Tariff – Rs 2999 + Taxes 
Data Usage – 60 GB Free
Download Speed – 8 Mbps
Upload Speed  2 Mbps
Additional Data Usage – 10 Paise / MB Upto 120 GB and 5 Paise / MB thereafter.
Do let us know if your experience on Line Bonding Broadband if you opt for this connection.