Virtualising the WAN for better performance

David Galton-Fenzi thinks WAN virtualisation could be the money-saver that network managers seek

To date, virtualisation has concentrated on the LAN, with virtualised servers or storage offerings aiming to boost efficiency. However, this does not translate to the WAN, where developments have been limited to frame relay, Multiprotocol Label Switching (MPLS) and VPN.

The WAN has defied Moore’s law, and the price of service has remained high and static because of this. MPLS is very expensive, with monthly per-megabit prices sometimes pushing thousands of pounds.

However, advances in the quality of commercial broadband services and developments in virtualisation have produced a new solution that is proving popular, in my view, due to the quick return it delivers: WAN virtualisation.

WAN virtualisation is based on the same principle as RAID. Cheaper disk options on their own are inferior, but if you virtualise multiple disks into an intelligent and reliable storage sub-system with its own file system and encapsulate them within an intelligent exterior, you will have enterprise-class storage.

The resulting appliance is employed by organisations looking to quickly increase the storage capacity of their computer networks.

WAN virtualisation applies the same principles. While MPLS itself hasn’t been getting much cheaper, commercial networks have. These do not claim the same reliability and security as MPLS on its own, but a virtualised pool of much cheaper commercial bandwidth that is encapsulated by an intelligent WAN virtualisation device does.

You can get high reliability by combining various public ISPs intelligently, creating a single virtual network with high-bandwidth connectivity.

This increase in bandwidth using inexpensive commercial ISPs can save organisations up to 90 per cent on their monthly WAN costs, I believe, costing £5 to £25 a month per Mbps as opposed to the £500 to £1,000 monthly for the MPLS equivalent.

The intelligent bandwidth shell is also suited to supporting high-priority data packets as it can detect any issues with available bandwidth and make sure labelled priority data is supplied constantly when needed.

APN devices can select network paths with the least packet loss and jitter for real-time VoIP traffic, and their ability to switch within a second to different network paths if affected by network throughput or packet loss problems.

Virtualising the bandwidth also allows APN technology to set a fall-back line which replicates the data flow without duplicating the data on the LAN, meaning that in the case of a signal failure, the prioritised videoconferencing call between the CEO and HQ doesn’t cut out at the crucial moment.

I recently read about a US company that had 28 sites, 19 of which benefitted from MPLS and nine from standard internet access. The MPLS connections were costing $111,058 per month and the internet access $2,485 per month – a combined total bandwidth payment of $113,543.

A conservative deployment of APN would save $64,911 per month on bandwidth costs and therefore yield RoI within four and a half months.

WAN virtualisation is different but complementary to WAN optimisation. While increasing the bandwidth can speed up all your applications, optimising existing network capabilities has proven popular with UK enterprises.

The use of WAN optimisation relies on a number of methods, such as data de-duplication, compression and Quality of Service (QoS). Companies are reluctant to add even more expensive bandwidth when existing capacity is not optimised.

The optimisation is designed to streamline the WAN connection and solve the associated latency (due to its wide area nature) and capacity issues. By caching data at either end of the WAN, warm transfers (data that has already been sent once) are speeded up and bandwidth is freed for other applications to use.

WAN optimisation also improves the performance of applications and processes, which suffer from increased latency due to the physical distance covered by a WAN. Increasing the available bandwidth will not significantly change how well distance sensitive applications work, but optimising the network with intelligent caching will.

I believe that WAN optimisation can also offer impressive RoI.

It surely makes sense to optimise current resources or intelligently virtualise cheaper ISP connections. However, WAN optimisation and WAN virtualisation are not mutually exclusive. In fact, I predict that companies optimising the WAN will be more open to the principles of bandwidth virtualisation.

David Galton-Fenzi is group sales and marketing director at Zycko