Many companies now use server and desktop virtualisation technology to consolidate the number of physical systems they need to keep powered up and updated. But when the users are spread over more than 40 sites throughout the UK, making sure each user has sufficient bandwidth can be problematic, as Noel Cresswell, IT director at specialist property lettings agent Leaders discovered.

Leaders was using IBM blade servers in its datacentre to host virtual machines (VMs) created using VMware Virtual Desktop Infrastructure (VDI). The VMs were accessed via the remote display protocol (RDP) by staff sitting at Wyse V10L terminals at around 40 remote offices.

“The RDP sessions are advertised as using anywhere between 50kbit/s and 128kbit/s per session, but the reality is very different. If you have eight people at a branch office using eight VMs, each consuming 200kbit/s, for example, the 512kbit/s bandwidth will not work very well,” says Cresswell.

Indeed, Leaders found performance degradation was so bad staff were waiting three to four minutes to download images of rental properties. Access to email and databases also suffered delays, as did applications such as Oracle, Microsoft Exchange and Aspasia – a bespoke letting agency tool.

While Leaders could have switched to using Citrix technology, and specifically the Citrix/ICA protocol, this would have meant sweeping upgrades to its systems architecture, says Cresswell.

Leaders is connected to an MPLS network via its service provider, and upgrading the wide area network (WAN) links at each of its offices would have also proved expensive.

After deciding WAN optimisation technology was the best route to take, Cresswell chose to install Expand Networks appliances at each of its branch offices, with another unit at the datacentre hosting the VDI. It was thought that Expand’s byte-level caching and dynamic compression technology was better suited to enabling RDP to be maximised than rival products from Riverbed and BlueCoat Systems.

Cresswell would not reveal how much the contract with Expand is worth, but believes he got a "very favourable" deal. Leaders preferred to do business with Expand itself, and calculates that the initial purchase cost of each appliance will be repaid within 16 months of its installation.

“Using a third party would have added to the overhead and we find that dealing with suppliers directly is more beneficial,” he says.

Being able to self-install a single piece of hardware to each office WAN link was also a big draw.

“Surprisingly, we did not have to make any tweaks at all. It was literally a case of unboxing the appliance, plugging in the network cables, and it started running straight away,” says Cresswell. “The most difficult part was configuring technology like hosted voice services where we had a bit of an issue with the virtual LANs (VLANs), but that was quickly resolved with the help of Expand’s 24/7 support.”

User response time has been considerably improved at each of the Leaders branch offices upgraded so far - around 60 per cent of sites have been upgraded to date. LAN and WAN performance has also stabilised, and all applications are reported to be running significantly quicker.

Cresswell says he is looking to spend £2,750 on an additional management module next year that will add remote, browser-based management capabilities to the current setup.