Application profiling: Available from companies such as Compuware, Mercury Interactive, NetIQ and Opnet, these software tools help network managers work with application developers by simulating how new or revised applications would run if deployed on an existing or upgraded network. By posing what-if scenarios and exploring various options, network managers and application developers can determine an application's footprint, chattiness and bandwidth needs and prevent an application from running poorly because of the application configuration or because network bandwidth is lacking. The software sits on a dedicated workstation or server.

WAN emulation: These products, from companies such as Apposite Technologies and Shunra, let IT managers test whether the application can withstand the increased performance demands of the wide area. For instance, Shunra's Virtual Enterprise runs transactions over a production network and measures the performance of the application against predefined service-level metrics. The technology also runs network impairments, such as latency, packet loss and utilization, against the application to test its merit against changing network conditions.

With Apposite's WAN emulator, network equipment and applications that would be used on opposite ends of the WAN link are installed on either side of the emulator. Users then configure the bandwidth, latency, packet loss rate, bit error rate and other parameters, and the WAN emulator applies these characteristics to the traffic.

Traffic-flow analysis: Companies such as Network General, Network Physics, NetQoS and NetScout deliver products that help network managers monitor application traffic in real time. Network-management tools that incorporate traffic monitoring, packet capture, bandwidth consumption and protocol analysis can show network managers the path of application packets. The response time at hops along the way remains a critical metric to measure, and IT managers should track such statistics consistently for capacity planning and trend analysis.

Such traffic-analysis tools, which can passively monitor traffic using probes distributed on key servers or strategically throughout a network, also can give network managers a real-time view of performance across IT silos such as servers, storage, databases and the network.