A US branch of Toshiba was having trouble finishing backup data runs over its fully meshed T3 network because of latency over long distances, but solved the problem using WAN acceleration gear. The equipment made by Silver Peak has enabled Toshiba America Electronic Components to cut the bandwidth it buys on some of the links from 45Mbit/s to 20Mbit/s, a savings that will pay for the equipment in 14 months, says Leon Roberge, the company's IT director.
The company has design centres in Minnesota, California and Massachusetts, as well as headquarters in California, connected by the T3s. It has a Chicago sales site connected to the network via a T1 that is also fully meshed with the other sites.
Roberge says Toshiba installed Silver Peak NX gear at all the sites and set up a set of fully meshed optimisation tunnels, so all traffic among all the sites gets optimised. The NX devices at opposite ends of WAN connections optimise traffic in a variety of ways to give better response times. These methods include TCP optimisation, compression and caching of data patterns at the far end of connections so the same patterns don't have to be sent over and over.
Initially the company wanted to boost performance over long distances where unavoidable latency was an issue, says Roberge, such as the link between Massachusetts and California. Tuning TCP window size with the Silver Peak devices helps most over very long distances, but it and the other optimisation methods have also helped on shorter runs, he adds.
The company has put a Silver Peak box in its Chicago sales office as well, which has less traffic and is fed by a T1. That line was filling up as the company started replicating its IBM/Lotus Notes data to company headquarters in California, Roberge says. He could have bought more bandwidth, but that would have been a continuing added expense, he says.
At each site, the Silver Peak box is placed between a switch and the WAN router so all traffic in and out of the site flows through it. "It's not just the engineering data, it's all of our data," he notes. Traffic includes access to Oracle data bases and passing CIFS traffic.
Toshiba initially installed no Silver Peak gear in its San Diego office because WAN latency between it and the San Jose office wasn't great enough to cause a problem. But after he saw the data reduction the devices were achieving at the other sites, Roberge realised that if he installed one at San Diego, too, he could reduce the volume of traffic between the two offices. As it turned out, he was able to cut the bandwidth he was paying for on the T3 between those offices from 45Mbit/s to 20Mbit/s. That savings made the Silver Peak investment worthwhile even if there were no latency improvements.
Toshiba started evaluating devices about a year ago. The company tried gear from three different vendors live in its network for four weeks at a stretch to judge how well they performed. Roberge would not name the other two vendors, but he says Silver Peak's gear pushed traffic through 25 to 30 percent more efficiently than the other they did. He says the differences in performance may be due to a combination of Toshiba's particular mix of traffic and Silver Peak's particular array of optimising tools. Another set of traffic might produce different performance results, he adds.
The company was limited as to how it could tweak WAN parameters by itself because it was using Network Appliance's Snapshot backup software that backs up only the changes made to files, Roberge says. Trying out several WAN acceleration vendors was essential because the difference in how well they handled Toshiba's actual traffic differed greatly.
"There' s a lot of marketing verbiage out there on what's best in your environment," he says. "I think the best advice is try it in your environment before you make the final decision. That's what we did."