Policy, Firewall Filter, and Class-of-Service Overview

Several mechanisms can help you control the way routing information and data packets are handled by a router—routing policy, firewall filters, and class-of-service (CoS) rules. Routing policies control how information is imported to and exported from the routing tables, acting exclusively at the Routing Engine level. Firewall filters examine packets at the entry (ingress) and exit (egress) points of the Services Router, filtering traffic at the router level. CoS rules determine packet scheduling, buffering, and queueing within the router. These three mechanisms are at the core of managing how a router forwards traffic.

You must have a license to configure a stateful firewall filter and Network Address Translation (NAT). For license details, see the J-series Services Router Administration Guide.

To manage the flow of information into and out of a Services Router, you must understand the fundamentals of routing policies, firewall filters, and CoS rules. To read this chapter, you need a basic understanding of IP routing protocols.

This chapter contains the following topics. For more information see the JUNOS Policy Framework Configuration Guide and the JUNOS Network Interfaces and Class of Service Configuration Guide.

• Policy, Firewall Filter, and CoS Terms
• Routing Policy Overview
• Firewall Filter Overview
• Class-of-Service Overview