There has been something of a religious war going on among performance monitoring tool vendors over the merits of synthetic transactions versus watching actual network traffic.
Simulated application traffic takes the client and server machines out of the equation.
Rather than measuring the response time for an actual transaction, which would involve processing on the client and server ends, packets that mimic an application data flow are sent between agents on either end of the network link being monitored. This lets you measure the performance of the network apart from all other elements that may affect performance.
The other alternative is to passively monitor actual data flows over the network. This gives you a better idea of what users are actually experiencing. True enough, but it also makes it tougher to troubleshoot problems; any element in the path could be at fault - network, server or client.
Thankfully, the religious war seems to be coming to an end as a number of vendors are incorporating both technologies into their products.
Ganymede, for example, this month is expected to ship a new version of its Pegasus product that adds the passive technique to the existing support for simulated transactions.
"The religious war is not doing anybody any good," says Jim McQuaid director of monitoring solutions at Ganymede. "Both techniques have value."
Concord last month essentially went the same route when it announced Network Health - Response, a new response-time monitoring utility for its Network Health network performance monitor.
"Now you can compare and contrast data sources, the synthetic vs. actual," says Kevin Conklin, vice president of marketing at Concord. Concord is also working with Ganymede, NetScout, Response Networks and Cisco to enable users to pull response time and/or RMON data from their tools into Network Health, letting the Concord product incorporate that data into its Web-based reporting engine. Additionally, Concord is now reselling a response time monitor from First Sense.
RELATED LINKS
You'll need a tool kit that includes performance monitoring gear, application modeling tools and, soon, neural network software. Network World, 9/20/99.
