InfoStor : Silver Peak optimizes apps over WANs, November 2007 Page 1

By Kevin Komiega

November 8, 2007—Silver Peak Systems this week announced several new optimization features for its NX family of WAN acceleration appliances, all aimed at overcoming packet loss and ordering problems that can wreak havoc on replication and remote backup applications across the WAN.

Silver Peak enhanced its Forward Error Correction (FEC) technology and added new capabilities for real-time Packet Order Correction (POC) and packet striping.

The addition of these new features to the company's appliances and Global Management System (GMS) enables real-time loss correction in high-capacity environments, ensures that out-of-order packets are re-ordered properly on the far end of a WAN link prior to delivery, and overcomes flow limitations in routers, firewalls, and other network devices for higher aggregate throughput and lower network latency.

Jeff Aaron, director of product marketing at Silver Peak, says if you don't fix problems in the WAN you will never be able to get high-performance applications to work properly. "Problems with dropped, lost, and out-of-order packets are becoming more prevalent as pipes are getting bigger and users send more data across the WAN," he says. "For example, if you hit a pothole in the WAN it can debilitate the entire replication process, and it will have to be restarted."

Packet-delivery issues become more problematic as data volumes increase, making them a big issue on high-capacity WAN links. According to Silver Peak, 1% loss on a typical WAN with 100ms latency will result in a maximum throughput of 1Mbps. This doesn't present a problem for typical office applications, but can derail a replication application that needs more than 100Mbps throughput to stay in synch.

Aaron also says as more enterprises move toward MPLS networks they are starting to experience packet-delivery problems. "While MPLS networks are cost-effective they are shared networks, which often means oversubscribed routers that drop packets."

In MPLS and IP VPN environments, packet-delivery issues can increase as throughput increases, which places more demand on network resources. Aaron says it is common to see averages of 0.5% packet loss with peaks reaching 5%, leading to excessive re-transmissions and slower data transfers across the WAN.

Silver Peak's new software capabilities are available to existing customers as part of the company's latest software release.

"The biggest applications where these capabilities have a tangible impact are replication and backups across the WAN. Out-of-order and lost packets are the biggest causes of headaches, and 50% of our customers have some sort of storage application in their network that is causing a pain point," says Aaron.

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