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Rollout: Shunra Virtual Enterprise: Page 2 of 4

The New Model

One of VE's new features is Transaction Manager, a standalone test tool that reports on transaction times. Also new is a library of WAN recordings for latency, loss, jitter and other characteristics. You can add on VE Analyzer, which processes packets captured on the appliance using a modified version of Ethereal. They are stored as Network General Sniffer capture files, reducing the need for an in-line tap. The installation includes a copy of WireShark for packet analysis, or you can use your own packet-capture software by defining the command line.

The network is drawn using Shunra's VE Modeler program, a Microsoft Visio application. Packet capture is enabled by placing a PacketList shape on the network diagram. The packet-capture length determines how much of an IP packet is captured. The VE has a 100-MB buffer and you can apply filters to capture or ignore specific packets.

We could have placed an in-line tap adjacent to the Shunra VE appliance and performed packet capture and analysis using tools like Fluke's Integrated Network Analyzer, NetQoS Analyzer and NetQoS Reporter. But these tools require separate analysis programs.

However, there is room for improvement with Shunra's packet capture. The 100-MB buffer is a bit small if you're running a long test. The VE appliance can be configured to roll the buffer when it fills, but future versions would benefit from a bigger buffer. Also, to stop the packet capture, you must stop the entire simulation. Often while testing, a network event like a precipitous drop in throughput bears investigating, but VE requires you to stop the simulation, investigate the anomaly, then start the simulation from the beginning again.