As the enterprise becomes more dispersed and applications continue to greedily gobble up precious WAN bandwidth, IT struggles to find ways to coax just a little more performance out of its existing circuits. All of the bandwidth in the world won’t reduce application response times as long as TCP and latency remain tightly bound together. In order to improve WAN performance, it takes digital sleight of hand to work a little WAN magic.
Enterprises that “buy only Cisco” infrastructure now have a solution to curing WAN performance woes caused by latency, inefficient application protocols, and oversubscribed circuits: Cisco’s WAE (Wide Area Application Engine). Using a combination of TCP optimization, proxy services, and byte-level and file caching, WAE does a good job speeding up sluggish networks and significantly reducing response times, even on first-time passes. Graphical reporting and monitoring provide adequate insight into traffic patterns and WAE effectiveness.
Back in rack
I received a full rack of Cisco equipment during my evaluation of the WAE — basically a distributed enterprise in a box. I tested the WAE 512 1U appliance (1GB RAM, 250GB disk; expandable to two disks) with a standard load of Cisco’s WAAS (Wide Area Application Services). Also available are the WAE 612 — 2GB RAM, as many as two 300GB disks, and the WAE 7326 — 4GB RAM, dual processor, and as many as six 300GB disks, each one providing greater scalability. The WAE 512 is intended for small- or branch-office deployments; the other two scale to the datacenter.
With the current release, the WAE connects out-of-band with the network, and it requires either policy-based routing or WCCP (Web Cache Coordination Protocol) v2 — the preferred method — to send TCP traffic to the appliance. WAE does not optimize UDP (User Datagram Protocol) and will pass it through unchanged.
The next version due out in early 2007 will allow for transparent inline installation. Furthermore, it will be available as a network module for ISR-ready Cisco hardware, making it easier for admins to get on the WAN optimization bandwagon with a simple installation into existing hardware.
To see how well the WAE performed, I integrated my Shunra VE and Windows SBS (Small Business Server) 2003 Server into the Cisco mix to allow me to generate test results consistent with previous reviews. After the bits had settled, I found the Cisco solution to be right in the mix of all of the leading WAN optimization appliances but lagging ever so slightly behind Riverbed’s Steelhead solution.
WAE’s CIFS performance was at its best when dealing with many small files, but only average when transferring a single large file, regardless of link speed and latency. One of my tests gauges CIFS performance during multiple file opens, edits, and saves. WAE showed marked improvement compared with nonoptimized connections (sometimes as much as 30 times faster), but only average compared with other WAN vendors’ solutions. MAPI performance showed good improvement compared with nonoptimized traffic, whereas FTP traffic — a single large ISO file — did better than nonoptimized but lagged results posted in my recent tests of Riverbed’s Steelhead.
WAE applies two caching techniques to TCP traffic to reduce response time and improve overall performance. First, as does the Steelhead, Cisco WAE caches both files and chunks of data on a local disk, with the file cache doubling as a local read-only file store when the WAN link fails. Additionally, Cisco’s DRE (Data Redundancy Elimination) caches byte segments — again, as does Riverbed’s solution — reducing redundant traffic on the WAN by serving the segments from the local appliance’s cache.
There is one major difference between each vendor’s byte segment caches. DRE segments in WAE are not shared among the various connected appliances. In other words, each byte segment cache is specific to the appliance pair that the traffic passed through. Riverbed doesn’t have this limitation and makes all cached segments available to any Steelhead pair. Riverbed’s larger pool of byte segments allows for a greater “first pass” match, which can help reduce traffic on first-time data.
Cisco’s application traffic policy engine is the smarts behind the scenes, determining how WAE will optimize a specific traffic type. Click for larger view. The appliance includes a well-rounded list of traffic types and allows IT to create custom definitions. This provides a way for admins to have very granular policies governing how traffic is — or is not — optimized and accelerated. I didn’t have to edit any of the default policies for my tests, and only in rare cases will IT need to dig into them. I like that the WAE allows for maximum flexibility yet isn’t overly complex to manage. The UI is well-organized and very intuitive to navigate.
A unique service to WAE is its print server capability, allowing IT to use the appliance as a centralized source for printer support by directly loading it with printer drivers. This is particularly useful for branch offices, where many WAEs will be placed, eliminating local file servers.
Report what you sow
WAE’s reporting engine is one of the best I’ve seen out of all the WAN optimization appliances I’ve reviewed. I was able to view traffic statistics based on many different criteria such as optimized vs. pass-through and reduction. I could also drill down into specific applications such as e-mail, messaging, and Web while choosing the traffic flow direction — inbound, outbound, and bi-directional. Consolidated reports are available when using a WAE as the central management point for appliances across the WAN.
It has been a long time in coming, but Cisco’s entry in to WAN optimization is a very solid effort that doesn’t leave any major feature out. It may not be the fastest appliance I’ve tested, but it is a very close runner-up and provides great overall performance improvement in all traffic situations. Reporting is well done, and setup is straightforward with little out-of-the-box tweaking necessary. If you have Cisco gear already in place, make sure you check out WAE.
Protocol support (25.0%)
Overall Score (100%)
|Cisco Wide Area Application Engine-512||9.0||9.0||8.0||9.0||8.0|
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