WAN Optimisation Day Two: What is WAN Optimisation anyway?

Client/server created the need for WAN Optimisation. In part two of our feature, Ian Yates explains the finer points of the technology.

Analysts at Frost & Sullivan have defined WAN optimisation as five different areas of technical focus. They talk about visibility in reporting, control and QoS, compression, protocol acceleration and application acceleration, and none of the experts we spoke with begged to differ. In fact, they all insisted if you don't find out what's actually traversing your WAN links, then you're not going to get the best out of whichever WAN optimisation product you choose. You might get lucky, and get a great result by just adopting plug-and-pray but then again, you might not.

"We actually believe people should not just jump into it right away," says Dimension Data's Roland Chia. "We actually stress the fact whenever we actually come across this is 'let's understand what you are trying to resolve', because a lot of vendors might promise this can actually improve your Citrix performance, improve your SAP performance but our experience actually tells us that it may not always be the case." And that's because proprietary protocols like those used by SAP and Citrix are already very efficient on the WAN. There are however, plenty of things that are not so efficient.

"So instead of just chucking in a box where you try to compress the other non-Citrix or non-SAP protocols, the cheaper way may be just a simple change to the queuing, change the policy on the routers and the network itself," says Chia. In other words, you need to know what's on the network. "Visibility of what you are running is ultimately crucial before you just let someone come in and chuck in a box, because it may not be the right thing to do, there maybe a cheaper solution."

Along with the increasing use of SSL to make WAN links secure, comes a major hurdle, because SSL traffic can't be compressed. However, the technology gurus have been hard at work on this problem, and nearly all the vendors now offer a solution by way of decrypting and compressing the traffic before re-encrypting and sending it out over the WAN, which of course requires another black box at the branch office to reverse the process. "Bluecoat actually came from the SSL world," says Chia. "So they were already good at improving the link if your traffic is actually encrypted. Obviously now everybody else is catching up - Packeteer's iShare can do that too and Cisco has a solution."

Chia also has a cautionary tale for systems administrators considering the move to Windows Vista. "If you look at Vista and Longhorn and these new offerings from Microsoft, the high end traffic is actually encrypted, believe it not, by default, on the LAN between client and server," says Chia. That's when you would really be glad that you'd put in something that would actually tell you what's happening on your network. Even if you weren't aware of Vista's preferences your network monitor would tell you 'here comes encrypted traffic' and you'd have an answer to the sudden slowdown on the WAN links.

Tomorrow: Here come the bad guys.

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