Network Instruments recently unveiled the GigaTrunk Probe, which the company says will make monitoring gigabit trunks easier for managers of large enterprise networks.

Gigabit trunking arose out of two needs, says Douglas Smith, president of Network Instruments: the need for more bandwidth than a gigabit link can supply and the need for redundancy and failover. Trunking adds capacity by combining links and typically offers ways for network managers to balance loads among those trunked links.

But managing the trunk itself can pose problems.

"The hardest part of doing gigabit trunking is synchronizing, properly timestamping and aggregating the data from multiple links into one big bucket," Smith says. "We are pulling that data together."

The GigaTrunk Probe, available now and priced between $25,000 and $33,000 (depending on the number of trunked links), passively watches and collects data in a non-intrusive way using test access points, or TAPs. The GigaTrunk Probe supports up to four gigabit links, carrying up to 8G bit/sec of traffic. To support these rates, the GigaTrunk Probe uses specially designed 64-bit, 66-MHz Gigabit Ethernet cards, giving the probe a way to guarantee data rate capture and analysis, the company says.

By connecting into the main arteries of a network through TAPs, Network Instruments says it ensures a passive monitoring option, which allows for greater efficiency than using a SPAN port on a switch. A TAP sits between a network switch and a server. It collects data in real time at the trunk level, and conversations can be viewed in aggregate across trunks or packet-by-packet for detailed investigations. The GigaTrunk Probe reports back to the company's Expert Observer or Observer Suite console.

The GigaTrunk Probe has a 4 Gigabyte packet capture buffer to capture and review 40 times more troubleshooting data than competitive offerings can, the company says. Network Instruments competes with NetScout and others.

Ann Bednarz is associate news editor at Network World.