A third of British IT managers fail to assess the impact that IT decisions have on their network, even though three-quarters of them say that the network is vital to their business. And the growing trend towards virtualisation is having a major impact on the way that networks perform.

According to a Computacenter survey of IT decision makers in the UK, 90 per cent of the respondents believe that virtualisation is making their networks worse while two-thirds of them believe that virtualisation is making their networks less secure - supporting the assertion made by Gartner earlier this week. In addition, 86 per cent of managers surveyed admitted that they had difficulties in pinpointing and solving virtual infrastructure bottlenecks.

According to Colin Williams, Computacenter practice leader for networking and security, "From discussions with our customers, we noticed that most of them were proceeding down the path of virtualisation without realising that it would have an effect on network traffic."

For Williams, one of the key elements is communication between the different departments. "What we often find happens is that the server guy has gone down the virtualisation path - normally with VMware - and the first that the network guy gets to hear about it is when he asked to provide an upstream link to the cloud."

The good news for Williams is that companies are realising that their approach has been wrong. "Most firms are now getting to understand that networks and servers can't work in isolation."

Williams has simple advice for companies considering whether their networks are up to the rigours of virtualisation. "Just stop what you're doing and don't plan any development until you've taken stock as to what you're planning to do tomorrow. And ‘by tomorrow' I mean very soon and not some point in the future."