Davis and his colleagues at Purina Mills tracked the traffic problems with SNMP traps, which could pinpoint only link troubles, not application-specific ones. So the company earlier this year decided to start prioritizing traffic to protect its SAP applications, which support the manufacture, order and distribution of its feed.

Purina Mills chose traffic-shaping technology instead of setting QoS (Quality of Service) parameters in its Cisco Systems routers. The company just didn't have the support resources to manage the four Cisco devices required to run QoS on its routers. According to Davis, that would have entailed installing Cisco's PolicyManager to implement the new policies and monitor the parameters on the routers, as well as using a separate reporting probe and CiscoWorks management software to pull data off the probe. "That's quite a bit of hardware and a big investment -- we can do the same thing in one box," says Davis.

So for traffic shaping the company installed NetReality's WiseWan switches, which provide in-depth reporting and analysis of traffic trends and problems, another feature that attracted Purina Mills. Davis didn't have to configure any routers with QoS parameters, just the WiseWan boxes. The biggest challenge to deploying the traffic-shaping equipment was setting different policies for each link. "You can't just put a policy in place for the whole network," Davis says. "There are different policies for different links -- initially, we have three policies per link."

SAP now gets top priority in Purina Mills' network and is guaranteed half of each link's port speed, e-mail has a medium priority and a maximum of 75 percent of the port, and so-called heavy traffic such as HTTP and FTP get low priority and are limited to 75 percent of the pipe. But even during a heavy SAP session, any leftover bandwidth is up for grabs by these other applications until SAP needs it again.

The two WiseWan boxes at Purina Mills' data-center site sit on the edge of the DS-3 pipe there, in front of the company's DSU/CSUs. Davis gets automated reports on subjects such as which plants are using SAP the most and where SAP is competing with less important applications -- like a large backup or other heavy traffic generated by a user. "We can find that user and educate him or her about appropriate times to run the nonpriority application, or implement a new policy" for that site, Davis says.

Interestingly, Purina Mills is now downgrading some of its 55 remote frame relay WAN links based on usage data gathered from its WiseWan switches. The WiseWan reports showed that some of Purina Mills' remote sites didn't need the higher-speed frame relay links, so the company will shrink the pipes at six of its sites, which should save nearly $10,000 per year in WAN costs.