DSL aggregation slashes price of bandwidth for smaller businesses

A Manchester-based service provider claims to have achieved a first-year return on investment of 60% for one of its clients by...

A Manchester-based service provider claims to have achieved a first-year return on investment of 60% for one of its clients by using traffic load-balancing tools to aggregate multiple DSL (fast data over phone lines) connections. This has provided large amounts of bandwidth for a much lower price than equivalent leased-line services.

Analysts have said that aggregating DSL in this way can bring cost savings for branch offices and small to medium-sized enterprises.

Supplier VGL is currently providing aggregated DSL connections to housing group Opal at three sites, with a further three to go, and will eventually provide connections for up to 800 users.

Load-balancing equipment from Rainfinity allows VGL to make use of much cheaper DSL connections where previously leased lines would have been used. VGL said a 2mbps leased line costs between £10,000 and £15,000 while the equivalent DSL line costs about £1,800.

DSL connections cannot be considered equivalent to leased lines because real bandwidth is impaired by "contention" from other users and because of the lower degree of reliability inherent in DSL technology.

But internet link load-balancing tools allow these issues to be overcome by providing a greater amount of bandwidth than would have been necessary with a leased line and then distributing traffic between connections to achieve a smooth flow.

Neil Rickard, an analyst with Gartner, said, "It is possible to aggregate connections going outwards using a router, but to do the same to incoming traffic from the public internet, load-balancing tools are required. Aggregating many DSL lines will give greater reliability and will increase bandwidth rapidly without putting the bill through the roof.

"DSL connections give a large amount of bandwidth for the money but may very often be over-subscribed and you will end up getting a lot less bandwidth than you think with contention. Also, service providers do not give such stringent service guarantees. This can be mitigated by getting DSL from different suppliers and load-balancing them."

Rickard added that the solution is best suited to users that need to move large amounts of data traffic do not require real-time delivery, as necessitated by video or voice connections.

Cost comparison

  • Leased line cost per year for 10mbps line: £50,000
  • 20 x 2mbps DSL business standard connection (£30,000) plus Rainconnect licence (£4,000) total: £34,000.

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