Overview

Policy management allows you to implement packet forwarding and routing specifically tailored to customers' requirements. You can create and implement policies, and assign those policies to profiles or IP interfaces. In this way, specified tasks will be performed on packets based on the criteria you define in the policy list.

Policy management uses policy routing to predefine packet flow to a destination port without performing a routing table lookup. Packets are sorted according to protocol or precedence into packet flows at ingress or egress by classifier control lists. Policy lists initiate actions specified by rules that can include classifier control lists.

Terminology

Table 7: Policy Management Terminology

Term	Definition
Policy lists	A policy list is a set of rules; each rule initiates a policy action. A rule is a policy action optionally combined with a classification. You can apply policy lists to packets that arrive at or leave an interface.
Classifier control lists	Classifier control lists specify the criteria according to which a packet flow is defined. The criteria include packet fields such as source IP address, destination IP address, source port address, destination port address, ToS byte, TCP flags, IP flags, and IP fragmentation offset.
Rate limit profiles	Rate limiting is the process of limiting either a classified packet flow or source interface at a configured rate that is less than the physical rate on the port. A rate-limit profile is a set of bandwidth attributes and associated actions. The NMC-RX application supports one-rate rate-limit profiles and two-rate rate-limit profiles.
Traffic classes	A traffic class is a systemwide collection of resources configured to provide a defined level of service to packets assigned to the traffic class. The resources consist of buffers, queues, and bandwidth. The NMC-RX application allows you to create traffic classes and assign them to traffic class rules, which are a part of policy lists.

See Table 7 for a list of common policy management terms.