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Overview ! 1

Chapter 1

Policy Management Overview

This chapter introduces policy-based routing management on E-series routers.

Policy management enables you to configure, manage, and monitor policies that

selectively cause packets to take different paths without requiring a routing table

lookup. The JUNOSe software’s packet mirroring feature uses secure policies.

This chapter discusses the following topics:

! Overview on page 1

! Platform Considerations on page 4

! References on page 4

Overview

Policy management enables network service providers to configure services that

customize the treatment of individual packet flows received on a subscriber’s

interface. The main tool for implementing policy management is a policy list. A

policy list is a set of rules, each of which specifies a policy action. A rule is a policy

action optionally combined with a classification. Packets are sorted at ingress or

egress into packet flows based on attributes defined in classifier control lists

(CLACLs). You can apply policy lists to packets arriving and leaving an interface. You

can use policy management on ATM, Frame Relay, generic routing encapsulation

(GRE), IP, IPv6, Layer 2 Tunneling Protocol (L2TP), Multiprotocol Label Switching

(MPLS), and virtual local area network (VLAN) traffic.

Policy management provides:

! Policy routing—Predefines a classified packet flow to a destination port or IP

address. The router does not perform a routing table lookup on the packet. This

provides superior performance for real-time applications.

! Bandwidth management—Rate-limits a classified packet flow at ingress to

enforce ingress data rates below the physical line rate of a port, A rate-limit

profile with a policy rate-limit profile rule provides this capability. You can

construct policies to provide rate limiting for individual packet flows or for the

aggregate of multiple packet flows. E-series router rate limits are calculated

based on the layer 2 packet size. To configure rate limiting, you first create a

rate-limit profile, which is a set of bandwidth attributes and associated actions.

You next create a policy list with a rule that has rate limit as the action and

associate a rate-limit profile with this rule. You can configure rate-limit profiles

Juniper E Series Configuration Guide

Other manuals for Juniper E Series