We're using 10 Wandel & Goltermann Technologies'
DA-30 protocol analyzers
to test the low-level performance of the Ethernet switches in our test-bed. You can configure the DA-30s to be single or dual analyzers for single network tests or for simultaneous operation on networks with different topologies. DA-30s monitor network traffic by capturing it in memory and then writing to disk for further analysis. They also can generate their own traffic for simultaneously testing other network nodes or components. For this article, we use the DA-30 as a traffic generator in its dual-analyzer configuration.
The DA-30's architecture divides network analysis into three sections: network interfacing, protocol analysis, and the us
er interface. Each section has its own processor working in parallel with the other tasks.
Based on an Inmos transputer, the network-interface processor handles the setup and implementation of up to 256 hardware address filters, time stamping, and communication with other processors. As many as four different interfaces (e.g., Ethernet, token ring, V.24, and LED displays) can be installed in a standard DA-30.
Another transputer serves as a protocol analyzer to capture frames at network speeds. The transputer executes multiple parallel processes, one for each layer of the OSI (Open Systems Interconnection) protocol stack and one for central control and interaction with the other processors.
The DA-30's third processor, an Intel 386SX, manages the user interface similar to how a 386 manages a typical 386 PC. It incorporates all the standard PC I/O interfaces. The AT bus serves as a communications link between the user-interface module and the two analyzer modules.
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The DA-30 protocol analyzer captures and generates network traffic.
The Analyzers
