Avoiding a super-highway pile-up with WAN tools

With demand on wide area and remote networks increasing all the time, bandwidth management solutions such as intelligent WAN acceleration tools will be essential to avoid major gridlock

Palmer: Even when you have a wide pipe, there can be delays beyond your control

Next-generation networks would seem to promise unlimited bandwidth and applications running freely across the WAN and remotely. But it is not quite as simple as that.

Our appetite for digital communications is voracious. Even when you have a wide enough pipe, you will get delays due to circumstances that are unexpected or beyond your control. In the end, you need some way of prioritising traffic.

Latency ­ not physical bandwidth ­ is the real performance killer. Bandwidth is not a synonym for speed but a measure of the data-carrying capacity of the connection.

If the amount of traffic is less than two million bits a second (2Mbps) the amount of bandwidth you have ­ whether it is 2Mbps, or 1,024Mbps ­ is irrelevant.

Even if a motorway has 10 lanes, it will still take you five hours to travel 350 miles if you are limited to 70 miles per hour. And with bandwidth the limit cannot be broken ­ it is the maximum achievable speed.

Two-way traffic
It is also important to understand that applications have to make a number of round trips when they are working. They do not just send lots of data one way and then the other; there is a stream of traffic going forward and back all the time. Available bandwidth is often largely irrelevant to application performance.

That point made, bandwidth can become an issue, especially on busy public networks. Service providers will usually put about 50 small businesses or homes onto a single 8Mbps ADSL line. If there are 10 users on the network at once, all using a significant amount of bandwidth, the effective connection speed to each is much less than 1Mbps.

This is going to happen more as people increasingly work at home and on the move. Customers will get a double whammy as bandwidth, as well as application latency, becomes an issue. Your business-critical application will have less room for manoeuvre and have to make even more round trips.

Application degradation
To head off any potential for degradation in application performance, first of all you need to prioritise the important applications. Second, you need to squeeze as much information down the pipe as you can by reducing the amount of actual information sent.

This is rather like zipping a large text file and reducing its size by a factor of 10. WAN acceleration can consistently send more than 20Mbps of data down a 2Mbps pipe by compressing it and removing repetitive chunks.

If the expected swine flu epidemic forces more people to work at home later this year, it may be that the UK broadband network will not be able to cope with the increased strain.

With too many people trying to get on the network at once, latency will become an even bigger issue.

The simple answer is to apply some kind of WAN acceleration technology and this is fine if all you need is a general uplift in performance. However, most appliance-based products tend to accelerate everything without really discriminating between one type of traffic and another.

That might improve performance, but only if you do not have too much of an overload to begin with.

What is required is a more integrated and granular approach, that enables
users to accelerate specific types of traffic or applications ­ applied intelligently, and with the correct management tools.

There is also going to be an increased need to give mobile and home workers some way to prioritise traffic so that they can adapt to changing conditions on the public networks. This would give them, and their businesses, much more agility and have a profound impact on productivity.

Ultimately, there is no reason why this kind of acceleration cannot become integral to applications so that both the network administrators and individual users can turbo-charge the software from which they require uncompromised performance.

It is always going to be a problem if too many people try to squeeze their data down a pipe at the same time, but as motorway protesters seem to argue, widening the road just leads to more people trying to use the same route and may bring the whole system to a grinding halt.

A more intelligent solution is needed and management of bandwidth is going to become absolutely vital in years to come. It is certainly an issue worth thinking about in advance.

Steve Palmer is product marketing director at WAN optimisation vendor DBAM Systems