Factors Affecting ADSL Performance

Posted: Monday, January 19th, 2009 at 20:05 by Neil Watson

Further to our communication on this site (http://noc.enta.net/?p=381) we write to explain the reasons for reduced performance over the past few days and to apologise for any inconvenience caused to customers. Please be assured that we are working to ensure normal service levels are resumed as soon as possible.

In our previous communication we advised that, as users re-authenticate in order to connect to the IPSC interconnect serving them, we expect user volumes and bandwidth demand to vary among the interconnects and to be unrepresentative of performance expected when all moved users are connected to IPSC. It is therefore possible that variable performance may be experienced, especially during off-peak hours, until such time that normal volumes are established.

The process of moving connections from IPStream Centrals to IPSC is being executed without issue. However, at the point of executing the move, it is not possible for Entanet to know which IPSC interconnect individual users will be connected to, as this information is not available from BT Wholesale. Furthermore, as complete execution of the move relies on users re-authenticating to establish their connection on the new interconnect, it has not been possible for us to estimate the total bandwidth required to serve them. It is not feasible for us to set an artificially high bandwidth level, as doing so commits Entanet to that level with BTW for a minimum 3 month period. Bandwidth usage is therefore being continuously monitored and adjusted as users re-authenticate.

Whilst managing an increase in bandwidth availability per interconnect it has also been necessary for Entanet to operate the Anti-Loss Tool (ALT) on IPSC as it does on IPStream Centrals, in order that all users receive service. However, in this unsettled period, at times the application of the ALT has uncharacteristically affected performance to a greater degree. Further incremental increases in the bandwidth level proved to successfully suspend the ALT, albeit only temporarily.

These affects are currently being experienced mainly in off-peak hours only. During peak daytime hours the available bandwidth results in some minor activation of the ALT. Nonetheless we regret that off-peak users have experienced differing performance levels than they are accustomed to and will continue to actively manage bandwidth to a successful conclusion.

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