Riverbed is teaming up with OpNet to give customers greater insight into what's happening on the WAN so they can better plan for bandwidth and resolve service-level agreement issues more quickly with service providers.

Riverbed's Steelhead WAN optimisation boxes will be combined with OpNet's ACE products that monitor and measure traffic and detect lags in application performance, and then analyse that data to project application impact on network performance.

The two companies are announcing that OpNet has joined Riverbed's Technology Alliance and that they will sell and market their gear together.

Coty, the cosmetics firm, uses Steelhead and ACE products in its network to troubleshoot performance of applications over its MPLS WAN, which is provided by Orange, says Glen Dalgleish, Coty's vice president of global information services.

When it is considering adding a new application to the WAN, Coty uses the ACE Analyst software to predict the impact it will have on application response time, Dalgleish says. If the Analyst shows that the new application will perform too slowly for users to tolerate, he can take steps to head off the problem before the application goes live.

For example, Dalgleish says he has tweaked web applications to make them less chatty as they refresh applets. In other cases where the applications could not be tweaked, they were not allowed on the WAN or were replaced with Citrix versions that use less bandwidth, he says.

The data gleaned from the two vendors' equipment enables him to isolate the cause of delay in application performance - whether it is server load, client problems or WAN shortcomings - and deal with them more quickly. He says the data is useful in talking to the WAN provider about SLA performance on specific links.

Later this year, the companies plan to announce support for OpNet software on virtual machines running on Steelhead devices to give even more detailed analysis of WAN traffic.

Riverbed has similar deals with other traffic monitoring vendors.