The walls between IT groups are crumbling, and network professionals report that responsibility for optimal application performance is shifting to them.

Distributed IP networks and complex real-time applications have forced a change. Now network managers need to be in the know from the start about application performance, helping developers understand what will work on a network, spotting poorly performing applications before users feel the effects and delivering LAN-like performance over the wide area to remote and branch offices.

"There are two kinds of network people in my mind: the ones that are just out of college and have all their certifications; and those that know the company's network, the applications that run on it and how to marry those two together," says Larry McBrayer, network architect for SaraLee Technology Services. "That's the difference between a contracted resource called in to troubleshoot a specific network issue and a corporate employee that knows the net, the business apps and how they should be working together."

McBrayer says his application performance duties expanded when his organisation installed Siebel software and couldn't get it working as desired. He used a combination of network tools from companies such as Network General and NetQoS, as well as application and system management products from BMC Software, CA and SolarWinds to better track down application performance problems. Ultimately it took a lot of tuning and tweaking by the network team to help the application team work out the kinks in the Siebel deployment.

"It's very cumbersome to explain Sniffer traces to an application developer," he says.

SOAP ups the stakes
The more companies explore service-oriented architectures, deploy VOIP or consolidate data centres to serve up applications from a centralised point to remote offices, the more network professionals are going to be called on to improve application performance, experts say.

"An intelligent or application-aware network places new demands on network managers," says George Hamilton, director of enterprise computing and networking at The Yankee Group. "They now have more responsibility for applications than just determining whether the network is the source of the problem. The nature of enterprise applications is such that network managers must be involved in their performance."

Hamilton says the key difference is between responding to events and alerts - delivered by typical network management software - and tracking performance and its subtle changes in degradation before services fail and customers feel the effects. Network management tools track faults and availability, meaning they will send an alert if a router doesn't respond to a ping, a server misses a pre-defined threshold or network services aren't available.

Until recently, most performance management tools would reside with the owner of the application. For instance, an application developer might use software from Compuware or Mercury Interactive to profile how an application would work on the network, test it in different scenarios and monitor response times on the server in a production environment to see if the expected and actual performance metrics sync up.

In the right place at the right time
With the two worlds converging, experts say network managers monitoring traffic are best suited to manage application performance in real time also. Network management tools that incorporate traffic monitoring, packet capture and protocol analysis can show network managers the path of application packets. The response time at different hops along the way remains a critical metric to measure, and IT managers should track such statistics consistently for capacity planning and trend analysis.

"My network monitoring and management teams are evolving into application-performance readers," says Stacey Thomas, senior manager of telecommunications for Continental Airlines. She uses Expand Networks technology to improve application performance on the WAN and NetScout products to track overall application performance. "We are able to help the application developers and the help desk team when application performance issues arise," she says.

Thomas says the evolution "simply makes sense" to her. Network managers consistently monitor traffic and bandwidth consumption, and she says spotting application-behaviour anomalies can be incorporated into those duties. With the network team's knowledge of speeds and feeds, Thomas says it can only further application developers' efforts.

"Network managers can help app developers - who aren't as well-versed in how an application can perform on 100Mbit/s links vs 128Kbit/s - understand how the application runs in the real world," she says. "They test on the LAN with local dedicated servers and can't always deliver the performance on the WAN, where the application has to depend on whatever bandwidth is available."

In the same vein, network managers get a full view of performance across the silos of IT and technology, says Mike Nix, assistant director of communications technology for IT Services at the Kansas University Hospital Authority. He uses tools from NetScout, SolarWinds and others to track network and application performance. He says spotting application issues should start to become second nature for network managers.

Early warnings
"There are indicators on the network before the applications start to degrade," Nix says. "The network team can see all the indicators and put the pieces together, whereas someone that focuses just on servers or apps only sees that much of the total picture."

Mark Maroclo, manager of systems support and engineering for Thomson Financial, describes it a bit differently. He says because he supports the tools from F5 Networks that see all the traffic coming in and going out of his network, he has also become the best watchdog for performance issues.

"Watching traffic separates the experts from the novices in network management," he says. "The best place to see application problems, which could normally be a mystery to solve, is in data coming off the wire, because if you know how to read the traffic, you can see what is really happening right in there."

Network General customer Jeff Duke, senior network engineer for the state of Indiana, agrees, saying he is not about to start writing code, but he knows his network expertise can help others to develop better applications: "If you build the network and are responsible for it, you should also be able to troubleshoot the apps on it, because you know how the network should perform."