Sitara brings QoS to branch offices

WALTHAM, MASS. - Sitara Networks believes it has the answer for ensuring quality of service (QoS) over low-speed lines.

The company last week announced a QoS appliance called QoSWorks. QoSWorks is designed for branch and remote office environments where WAN speeds top out at T-1/E-1.

In the LAN environment, where bandwidth is inexpensive, users administer QoS just by throwing more bandwidth at applications. But in the WAN, where bandwidth is at a premium - indeed, 88% of frame relay links are 128K bit/sec or slower, according to Sitara - QoS administration is a science.

QoSWorks is designed for companies looking to engage in e-business but wary of sharing bandwidth for business applications with e-mail, Web browsing and streaming media. To help reserve bandwidth for the applications that need it most, QoSWorks classifies traffic and allocated bandwidth based on priority policies established for specific traffic classes.

Bose: Europe calling

Audio equipment maker Bose in Framingham, Mass., is using QoSWorks initially to classify traffic on two 64K bit/sec WAN links - one to Europe and the other to the southwestern U.S. Applications running on the links include HTTP, Microsoft Exchange, TCP and UDP, and LAN bridge traffic.

"The first step of the game is to just characterize the traffic based on these protocols. Then the next step will be to actively manage it and set priorities so we can give performance to those things that are more critical," says Rob Ramrath, director of corporate information services at Bose.

It may be obvious that Exchange traffic would take precedence over HTTP data, but Ramrath says that may not be the case.

"When you hit a send button on your Microsoft Outlook menu, do you know or care that that message shows up in your receiver's inbox in three seconds, 10 seconds or four minutes?" he asks. "However, when you're browsing the intranet and you hit a link, you certainly care how fast that comes up. So until we really examine it, I wouldn't necessarily know which ones we're going to jump to and prioritize."

QoSWorks is a hardware device with two 10/100M bit/sec LAN ports. One connects the device to a LAN switch or hub, the other to a WAN router.

QoSWorks classifies traffic using four schemes: class-based queuing (CBQ), TCP rate shaping, packet-size optimization and an algorithm for fair allocation of bandwidth by connection.

CBQ classifies traffic and queues it based on that classification, while TCP rate shaping bypasses queuing by applying flow-control policies to individual traffic flows and classes of flows. Packet-size optimization manages latency by reducing the size of the packet; and fair bandwidth allocation doles out an equitable share of bandwidth for all connections within a class, so that individual connections do not time out.

These four methods are designed to guarantee consistent response time for latency-sensitive applications, and deliver granular control over bulk transfers such as e-mail and Web browsing.

QoSWorks also includes a caching feature for improving the response time for HTTP traffic and increasing network performance. QoSWorks' caching does not require reconfiguration of routers or browsers or deployment of a switch, Sitara officials say.

QoSWorks competes with bandwidth managers such as Packeteer's PacketShaper, Lucent's Xedia Access Point routers, and caching engines from CacheFlow. Sitara officials claim that QoSWorks is more full-featured than these products because the appliance combines rate shaping, class-based queuing and caching in one box, whereas competitive offerings rarely feature more than one of these capabilities.

QoSWorks also lets network managers avoid the costs and headaches of deploying multiple-point network performance products.

Pricing for QoSWorks starts at $3,000 for 64K bit/sec maximum throughput, $5,000 for 384K bit/sec, and $10,000 for 2M bit/ sec. QoSWorks will be available later this month.

Sitara: www.sitaranetworks.com.