Traffic management, Packet shaping and the Cloud.

The Cloud is growing in acceptance, all the various types of service are valuable. We at enVirtua use the cloud for our Cloud Based Backup product. We use Amazon EC2 instances when we need a server to test on, and we use SaaS (Software as as Service) here there and everywhere.

A big issue that we see hindering acceptance of “The Cloud” is corporate bandwidth use. Not the size or quality of connections, rather then availability on those “pipes”.

Congestion is quite simply a complete killer to cloud based solutions, especially in the large enterprise. Less so in the smaller organisation, or home office… simply because there are less people and you can control behaviour better.

In the large organisation, a congested pipe can be a huge issue. The larger the organisation, the larger the number of users, applications and bandwidth consumption.

It is not uncommon to see a 20MB connection maxed out, with performance issues being common. More often than not, there are performance issues and no visibility as to what the actual problem is. Intuitively people blame the size of the bandwidth connection, “the network is slow we need more bandwidth” is a phrase often heard when there are issues.

Quite often organisations invest in bigger and bigger connections, often without actually even looking at the amount of bandwidth being used, let alone what is using the bandwidth.

Traffic monitoring and shaping is the solution to spiraling bandwidth costs.

There are three key area to a traffic management solution, monitoring, shaping and compression. When used together, these three areas can solve many many performance issues and we have seen examples where WAN links were able to be made smaller rather than larger; whilst performance and user experience increased.

If you have Cloud based applications, it is important that you know how they are being affected by congestion. You need to be able to ensure that the important services work well, whilst ensuring that all services work to acceptable levels. Having a cloud based server is only as good your ability to connect and work on it.

Monitoring.

The first thing to do is to ensure you can see what is traversing your WAN links. This means looking both at the raw amount of bandwidth used over the WAN. However you want to know what applications are consuming how much bandwidth. You’d be surprised at how many large enterprises are having mission critical application performance affected by web traffic from sites like YouTube, ITV and the BBC iPlayer. You also want to look deeper and be able to see response times for example.

Shaping.

Having identified what applications, servers and users are using your bandwidth, it is time to “shape” that traffic. Shaing consists of putting limits and gurantees on the amount of bandwidth specific applications can use. The RDP (Remote Desktop) session to your Windows 2003 server on Amazon AWS might be more impotant to you than say email traffic. In this case, you might guarantee and prioritise RDP so that it has the higest priority and 1mb of bandwidth to itself. email traffic might be low priority and given only 500k of bandwidth.

More sophisticated shaping might be to gurantee Citrix traffic generally 5mb of traffic, whilst ensuring each individual Citrix session has it’s own protected bandwidth and priorities.  Once all the protected individual bandwidth allocations is used, perhaps you want to prevent more users connecting, or simple let them have a lesser service?

Another typical shaping task is to throttle to almost zero nuisance or banned traffic. In most corporate environments, giving 1kb/s of bandwidth to bit torrent or streaming video is common. The same is true of instant messaging traffic or Skype, which is very often throttled. Email traffic is often throttled back, but traffic to Blackberry devices given high priority.

Compression.

Some traffic can be compressed, take that traffic and basically zip the data up so that it uses less bandwidth. Many traffic types are candidates for compression, some however should most definitely NOT be compressed. For example, our Citrix traffic from the example above should not be compressed as the traffic is already compressed by Citrix, so attempting to compress it is actually increasing delays.

When you combine these technologies, you can get very fine grained control over the bandwidth your business uses.

Common Mistakes

Not having visibility of which applications are using the WAN bandiwdth is the most common problem we come across. This comes in two flavours, those that have no tools in place and those who have the tools but do not have regular reporting occuring. The monitoring tools are often used in a reactive manner. Someone complains and then IT staff go login to the monitoring tool and take a look. This often results in teh IT team missing the problem as it has already passed.  Regular reporting and identification of trends is more effective use of the technology once shaping has been implemented.

Too many rules (too fast) is the second biggest problem. When a shaping solution is implemented, often a large swath of changes are made in a short period of time. The impact of these changes can be quite destructive, and more knee jerk changes are made to correct them. After a period of time there are many many rules and often the reasons for implementing them is lost and the results are not often compared against the desired outcomes.

The final problem, perhaps is in fact the worst, is dust. After an initial burst of use, the traffic shaping solutions are left in a rack to gather dust. The IT environment continues to evolve, but the WAN shaping rules remain static. The rules that were initially helping the situation can quickly start causing performance problems. If you begin implementing Cloud based solutions the rules need to change to ensure that the shaper is not having a detrimental effect and is in fact ensuring that the cloud services are optimally available.

enVirtua have experience at providing regular reporting and tuning of the market leading Packetshaper solution (as well as others). We are able to provide a service whereby we will provide you monthly reports on your WAN traffic and also propose and implement changes to your shaping configurations to ensure optimal performance.

Please contact us on 020 7193 8987 to discuss the details.