The average organization shares bandwidth across many workstations. Especially in times when costs have to be slashed and businesses are still expected to run as optimally as possible, you have to figure out ways in which you can recycle or salvage as much as possible.

But regardless of size, the internet pipe that comes into your office, well, can be a bit leaky. While this doesn’t mean that you have to make the connection more controlled, it does require a little better understanding of the how connectivity works, so that you can make the most out of it.

Bandwidth
As Wikipedia defines it, the movement of information in the Internet is achieved via a system of interconnected computer networks that share data by packet switching using the standardized Internet Protocol Suite (TCP/IP). It is a “network of networks” that consists of millions of private and public, academic, business, and government networks of local to global scope that are linked by copper wires, fiber-optic cables, wireless connections, and other technologies. Accessing information across your Wide Area Network, or WAN, is relatively similar.

But in order to better understand the problem, you have to take a closer look at the way people access the Wide Area Network. Take the example of a bank. Regardless of the ERP it is running, various branches within the bank need to be connected to one another. Because these are relatively high-traffic, high-intense and often critical transfers, you need to be able to optimize the connectivity you have across the WAN.

WAN links can be the connectivity between multiple offices of the same organization such as banks or can be simply the internet connection from one organization to their ISP. Too much bandwidth is wasted on the WAN because of repetitive data patterns and protocol limitations. You actually end up wasting money on expensive WAN links such as leased lines, DSL, wireless or satellite connections in trying to increase your interactivity with the WAN when you could perhaps resolve some of the issues through WAN optimization products.

If there is a lot of lag on your network and your sessions time out or simply don’t go anywhere, the power and efficiency that technology should be giving you, becomes meaningless. Productivity is lost as users have to wait longer to transfer the information.

How Bandwidth is Wasted
There is generally lots of repetitive data on the WAN which can be intelligently handled to reclaim the wasted bandwidth.

For example, a large 10Mb PowerPoint presentation is being sent back and forth between two workstation  via WAN with only a 5% modification in each transfer. Lots of productive time is wasted waiting for the transfers as the entire file is sent over the WAN despite the fact that 95% of the file was same. If you had a smart traffic cop sitting at each end of the network where this transfer was taking place, this could be quite intelligently handled. The network could intelligently transmit only the 5% difference in the file and provide the complete file transparently to the remote user quickly.

Another example of repetitive data can be Hansmission the workstation of teller at bank, who is transmitting hundreds of similar transactions of money deposited & withdrawn to the central computer at head office.

All of these transactions appear as similar data pattern on the WAN, except for the account numbers and the amount in the structure of data. Since the sequence of this transaction data already exists at the source and the destination, the network should be able to compare the difference and only transmit the tiny information across the WAN containing just the non-repetitive data.

The second reason for bandwidth wastage is based on protocol limitations.

Here’s an interesting example to explain this. A company has 2 offices across the Atlantic in London and New York. The company has a 100Mb link between these offices. The way several file sharing protocols such as Microsoft CIFS works is that they require acknowledgements after every few blocks of data are transmitted. Due to the long distance between the offices, the acknowledgements take sometime before they reach back to the sender and the sender does not send any more data until it receives the acknowledgement of the previous ones. Typically, a file transferred over such WAN will get less than 30-50% overall throughput and more than 50% of the bandwidth will remain unused and wasted.

WAN Accelerator products handle these problems effectively and can give you up to 100 times more throughput on your existing WAN. The WAN accelerators are typically used in pairs, one on each side of the WAN. That’s how they “talk” to one another.

Solutions
To eliminate the repetitive data issue, a WAN accelerator typically chops the incoming data stream into smaller blocks of data and saves them locally. A file of 10MB may be chopped into 400,000 blocks of 200 bytes each and then saved locally on the hard disk of the WAN accelerator. Once the same file comes again with or without any changes, the WAN accelerator will match all the blocks with the ones it has already seen in the past, and replace those blocks with smaller labels before transmitting them over the WAN. The remote WAN accelerator will remove the labels and replace them with actual data before delivering them on the LAN.

In order to overcome the issue with WAN links with high latency, protocol specific acceleration techniques are used to achieve the most effective use of the bandwidth. For instance on a long haul or satellite link using Microsoft File sharing between Windows Computers, the WAN accelerators can send pseudo acknowledgements to the sender locally, so that the sender does not have to wait for the real acknowledgements from the receiver before sending more traffic.

Similarly, there are other application specific acceleration features for applications like Microsoft Exchange and HTTP that increase the performance of these applications by manifold.

Products
Although there are many products available from different vendors, let’s highlight a few of them. All vendors have their products available in different sizes suited for different range of WAN bandwidths.

Juniper WX series, formally Peribit Networks, is the pioneer of WAN Acceleration technology. Their products are quite strong in the compression and sequence reduction domains. Juniper also recently integrated the WAN acceleration into their popular J-series routers through an add-on module. With the addition of WAN acceleration, a customer can have a fully integrated single box for his branch office, which has integrated DSL/Serial Interface, LAN switch, Router, Fire wall and WAN Accelerator in a single appliance.

Riverbed Steelhead Appliances are currently regarded as the market leaders with their strong performance in Microsoft CIFS acceleration. They have different product sizes which are licensed by a number of sessions unlike Juniper, which has its licenses based on bandwidth consumption.

Bluecoat is the market leader in web proxy, caching and content filtering technologies. They recently introduced WAN acceleration software add-on called “Mach 5”, which optimizes the WAN through a combination of 5 different technologies. Bluecoat combined their strong object caching technology in WAN acceleration, which can cache entire files in addition to blocks, which results in more throughputs for certain kind of traffic.

Expand Networks have launched a VMWare version of their appliance, in addition to the existing hardware appliances. These virtual appliances can be loaded on a VMWare server that can be already hosting other production systems. The traffic routed through the Expand Networks Virtual Machine is accelerated to any other site having a WAN Accelerator Appliance or Virtual Machine.

Every problem has a solution. A lagging network doesn’t always mean that you need to pile on more bandwidth or higher speed connectivity. Take a close look at the situation to understand and identify the problem. Once you know what the issue is, a WAN accelerator might just be the solution you are looking for!

Gartner’s Magic Quadrant for WAN Acceleration

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