Network managers of global or multisite enterprises are all too familiar with the degradation that affects networks as traffic volumes escalate. When competition for bandwidth exists, there is no way to identify and assure the passage of mission-critical data across a network. With multisite enterprises increasingly dependent upon their network-intensive, mission-critical applications, unpredictable performance is not acceptable.
Policy management is a way for network managers to automate administration of quality-of-service facilities on the network. In a policy-based network management system, you create policies that are simply rules for prioritizing traffic from certain users and applications. The system also stores information about each network device's capabilities. It converts the policies you enter to configurations for the routers and other network devices that handle data traffic.
Most major equipment vendors, including Cisco, Nortel, 3Com, and Lucent, have developed policy management systems for their products, but unfortunately none interoperates with the others. A few independent companies such as Orchestream are attempting to build multivendor systems, but even those companies support only one or two vendors, though more support is promised down the road. However, as standards mature and vendors gain experience working with them, we should begin to see interoperability improve.