Channel 4 revamps main network to prevent outageBy Antony SavvasChannel 4 has revamped its main network to ensure business continuity in the case of an outage.The broadcaster has deployed new network switches from Extreme Networks to support a new wide area network (WAN) that supports a revamped data centre and a new external disaster recovery site that is up to 100km away. The DR site receives mirrored business and production files.Channel 4's head of operations Bruce Rawstorne said the legacy network was "like a Mini fitted with a Ferrari engine".

The network already used Extreme Networks Black Diamond switches that could serve an operation many times larger. The 40GB backbone linking the two sites was also over-provisioned with dark fibre.

Rawstorne said: "This was the first company I'd worked for where the network was not the issue. Normally, when anything goes wrong everyone begins by blaming the network - they'll do anything rather than admit that the fault lies in their own systems."

The legacy network was designed for supporting massive media file transfers rather than more normal business applications. What was now being planned did include mirroring production storage clusters between the two sites, but this only required the transfer of incremental updates, rather than full files, once the mirrors had been initially aligned.

Rawstorne said so much spare network capacity meant that IT operations between the two data centres had grown organically into a campus-style network, without the usual discipline of limited resources. Such a system would prove costly and inefficient if migrated to a remote data centre in its current state, he said.

What was needed was a "slimming operation" towards a leaner, less wasteful network that could more readily link to a remote data centre with an outsourced connection, Rawstorne said.

While latency was not a problem in the old network, the two data centres would be up to 100km apart and connected by a 20GB virtual private line with a number of DWDM (dense wave division multiplexing) channels, instead of dark fibre. This means that latency could also become an issue for certain applications.

To address all the issues Rawstorne said the company considered switch capability, throughput, how various suppliers' technology was developing and price.

He said: "The cost of the new Extreme solution was considerably more attractive and it offered sufficient spare capacity."