the Pipeline

Reality bytes

ClearSight Networks has released the ClearSight Packet Generator, a network analysis tool that enables users to simulate network traffic conditions, test network capabilities and tweak network designs. Testing is necessary for evaluating and detecting problems before implementing new system components.

One early user of the product, a small systems integrator called Netco Government Services, combines Packet Generator with other tools to simulate network design changes using real network data, said Matt Holbert, chief architect at Netco Government Services.

Holbert and his team capture live network data and bring it back to their laboratory, he said. They then use Packet Generator to run the data through various network configurations.

"Since we have the captured data, we're able to replay it several times," Holbert said. "If we make a change, we can see the effects. Then we can make further changes and test it again."

By running the tests in the lab, the integrator's employees don't have to interrupt the customer's operations while refining the network design, Holbert added.

Storm in a teacup

Trying to capture data can be like trying to use a teaspoon to drain Lake Superior. Data flows so fast and in such density that technologies to capture it for analysis — whether in real time or retrospectively — fall behind and are limited to snapshots.

Network Instruments has recently released two related products to try to alleviate that problem. The Gen2 Gigabit Capture Card captures all data at up to 250 megabytes/sec. The GigaStor Probe provides up to 4 or 8 terabytes of storage, so that network administrators can analyze days or even weeks of captured data. The probe includes the Gen2 card.

The GigaStor product is better than its predecessor, said Charles Thompson, sales engineering manager at Network Instruments.

"When we developed the first generation of the GigaStor Probe about a year ago, we developed it in response to some needs we saw in the market," he said.

One common problem is an inability to troubleshoot sporadic network programs, he said. Because network managers are limited in their ability to capture data, a problem that persisted for a few seconds would often be impossible to analyze.

"By the time they are ready to do a packjet capture, the problem had disappeared," Thompson said. If managers can look back through several days' worth of continuously captured data, they can find the data packets associated with those events, he added.

"A fraction of a second was all the visibility you'd have," he said. Using GigaStor, "they don't have to be in place waiting for the event to occur. The unit sits on the network passively gathering data."

The GigaStor unit performs all the necessary processing, making it easier to administer a dispersed network over long distances. The unit crunches the numbers and sends only a screen shot to the network manager in a remote location. The manager can act on the information displayed on the screen, but because the actual data doesn't need to be sent, the bandwidth demands are low.