Virgin Media updates traffic management policy to reflect new products
Monday 02 April 2012 14:04:30 by Andrew Ferguson

Virgin Media who revamped its product range to make its 30 Mbps service the slowest product that is available to new customers last week has now published details of how its subscriber traffic management and file sharing traffic management will operate on the products.

With upgrades for existing customers still under way, the matrix of products is more complex than many people will easily be able to digest. The subscriber traffic management for downstream and upstream is independent of each, so exceeding the upstream trigger level should not affect downstream and vice versa.

The file sharing traffic management is based upon Virgin Media allocating bandwidth across its network for peer to peer and newsgroup traffic, thus if the total usage in these areas is less than the limit people will run at the the maximum possible speeds. If the limit is hit then speeds across the whole network will be cut back, basically peer to peer and newsgroup users would be contending with each other for that type of traffic. The time period when the file sharing is managed is 5pm to midnight during the week, and midday to midnight at the weekends.

"We want all our customers to get the best possible broadband service. That means speedy downloads for all customers – not just a few. When someone is downloading and/or uploading a particularly large amount of information over a long period of time, it can slow down the broadband speed for other users in their area who might just be checking their email or browsing the web. That’s why we occasionally moderate the speeds of customers who are downloading and/or uploading an unusually large amount. That way, everybody gets great speeds and all our customers stay happy."

Description of Subscriber Traffic Management

Reading the subscription given to customers one gets the impression that it is possible for the actions of a single user to cause congestion, one hopes that Virgin Media is not running its network that close to the limits. Best practice is to have a network that only offers a maximum speed several times above the maximum speed that any single customer can use. In the distant past, when Tiscali offered 1 Mbps DataStream connections, it would have just 2Mbps of backhaul, and populate this with 100 customers (50:1 contention ratio), and thus the pipe would often be congested in the evenings, rendering latency sensitive activities like gaming impossible.

Virgin Media is careful to avoid the word unlimited on its product pages, using the phrase 'Download as much as you like with no hidden charges', the question is whether the STM system is only reducing speeds by what an average user would expect from an unlimited service. The quoted typical speed on the up to 30 Mbps of 30.62 Mbps, obviously means that the typical user is not someone who regularly triggers the STM system.