Expand has been in the WAN-optimization market for eight years, longer than most vendors. The company has refined and improved its products relentlessly. The Accelerator 6910 and Accelerator 6940 devices Expand submitted for testing at our Alabama network lab were particularly effective WAN-traffic front-end processors. They were reliable, scalable and easy to configure.

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Expand Networks' considerable experience in reducing and prioritizing WAN traffic showed in the Accelerator 6910 and 6940 appliances. In our opinion, the 6910 is appropriate for smaller, regional data centers, while the 6940 is best suited for a central site that can handle aggregate traffic from several 6910 devices, for example. The 6910 appliance can easily shoulder a workload of 10Mbps and as many as 50 remote sites, while the higher-performing 6940 has a capacity of as much as 20Mbps and 200 remote sites.

Working together, the 6910 and 6940 units achieved an average bandwidth-increase factor of 6.2. They fared well with Citrix, Oracle and VoIP traffic, accelerating the related traffic by an average bandwidth-increase factor of 11.0. Impressively, they attained a blistering average bandwidth-increase factor of 22.6 for Web, e-mail (Exchange and Notes), FTP and file-sharing (Network File System and Common Internet File System) traffic.

Our analysis showed the units definitely would let us tell our telco to dial back a full T-1 link to a fractional 512Kbps link yet still enjoy the same throughput. This would typically save about $1,000 per month, per link.

Traffic shaping

The units we tested operated at or near wire speeds, introducing virtually no latency. The 6910's and 6940's traffic-shaping feature offers high, medium and low inbound and outbound congestion control. We prioritized Oracle, Web services and file-sharing traffic while relegating e-mail and HTTP traffic to the back of the queue and found that during busy times, our business-critical traffic zoomed through the links ahead of less-important data.

WAN OPTIMIZATION ACCELERATOR 6910 AND 6940 Expand Networks

4.2

Price: Model 6910 starts at $9,000; Model 6940 starts at $13,000. Pros: Scalable; near zero latency operation. Con: Needs clearer documentation. The breakdown Performance 30% 5 Scoring Key: 5: Exceptional 4: Very good 3: Average 2: Below average 1: Subpar or not available Protocol support 20% 4 Ease of use 20% 4 Scalability 20% 4 Documentation/installation 10% 3 TOTAL SCORE 4.2

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Furthermore, both units have a transparency mode for MPLS traffic that lets a telco or service provider identify MPLS packets within a compressed, optimized datastream and give them higher priority.

Both units recognized and accelerated the HTTP, DNS, FTP and TCP protocols by providing anticipatory acknowledgments and larger TCP windows. The devices also contain application-specific discovery and acceleration technologies for more than 100 predefined data flows, including Citrix and VoIP. The devices are Remote Monitoring/RMON2-capable, and both integrate well with Cisco's NetFlow.