Businesses should expect to face a wide and confusing array of choices when seeking the right WAN-acceleration gear to make transaction times tolerable as they shift from branch office servers to centralized server farms.
Centralization reduces the number of servers and so saves capital and maintenance costs, and improves security. But it also means more end users access data via the WAN - users who will scream if performance degrades as a result.
Availl, Cisco and Brocade offer products tuned to speed up specific types of WAN traffic - wide-area file services or WAFS - which represent a large chunk of the new WAN traffic that results when servers are centralized. But a throng of other vendors says its more broadly focused gear is better suited to real customer needs. All WAN traffic can benefit from acceleration, they say, and not all WAN traffic is WAFS.
This more broadly focused equipment can boost the performance of a range of network traffic, not just WAFS, although some vendors are tuning their gear so it gives special treatment to WAFS, as well. These WAN-acceleration vendors include Array Networks, Converged Access, Expand, Juniper, Orbital Data, Packeteer, Riverbed Technology, Silver Peak Systems, Swan Labs and others.
As an example of this tweaking for WAFS, Packeteer this week is announcing a software download for its PacketShaper appliances that can target priority treatment for Microsoft Windows Server 2003 R2, as well as Active Directory, Exchange and distributed component object model traffic. Packeteer also is teaming with Tacit Networks to provide a separate Tacit appliance that caches data in branch offices as a way to speed WAN transactions.
A crowded field
The WAN acceleration field is crowded because vendors have the opportunity to get a cut of the $5 billion spent this year on branch office infrastructure, and that number will rise next year, says Cindy Borovick, director of data center networks for IDC.
If the devices can help data center consolidation by boosting performance, they can pay for themselves over time, making them attractive to corporations, she says. But the variety of vendors and the varying mix of techniques they use mean customers have to do their homework to find the product that is best for them.
All the gear in question have certain things in common. For instance, they are generally deployed in pairs at either end of WAN connections, prioritizing and altering traffic to make it cross the links more efficiently.
Vendors are dealing with a common set of problems rooted in the fact that WAN bandwidth is less than LAN bandwidth, making response time slower for each traffic type as it waits its turn. As applications compete for this bandwidth, those that are less important to the business might disrupt more critical ones unless something is done about it.
Competition for bandwidth is compounded by network delay in cases where traffic crosses long distances and by the slowing effects TCP has when it throttles back transmission rates to make up for what it perceives as network congestion. The result can be applications that perform so poorly that end users complain, or worse, don't use the applications as they should for best productivity.
To handle these problems, vendors have an array of technologies, including compression, caching, prioritization, application enhancement and TCP acceleration. Not every vendor uses all of these and each might use a different mix. As a result, acceleration devices from one vendor might provide more improvement than devices from another even though they are placed on the same link and try to speed performance for the same traffic.
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