文档介绍：JUNOS Routing Policy
Course Objectives
u pleting this course, you
should be able to
v Describe routing policy features
v Configure routing policy in a variety of
situations
v Configure advanced routing policy for BGP
◆ munities
◆ Manage AS path regular expressions
◆ Set route damping parameters
= Slide 2
Basic Routing Policy
Module Objectives
u pleting this module, you
should be able to describe
v When to define routing policies
v The difference between importing and
exporting routes
v The basic structure of routing policies
v Match conditions and actions available for
policies
v How to define route filters
v How to apply routing policy
= Slide 4
Overview
Policy Overview
u Controls routing information
transferred between routing table and
each routing protocol
v ing routing information can be
ignored or changed
v Outgoing routing information can be
suppressed or changed
u Some match conditions are protocol
specific
= Slide 6
When to Apply Policy
u You do not want to import all learned
routes into the routing table
u You do no want to advertise all learned
routes to neighboring routers
u You want one protocol to receive routes
from another protocol
u You want to modify information
associated with a route
= Slide 7
Import and Export
u Policy filtering is done with respect to the
JUNOS routing table
u Export policy is applied to active paths in
routing table
Neighbors Neighbors
Import Export
Routing
Routes Routes
Table
Protocol Route Selection Protocol
Policy
PFE
Forwarding
Table
= Slide 8
Routing Policy
u Allow you to filter and control routing
information entering and leaving the router
u Separate policy for each routing protocol
Neighbors Neighbors
Import Policy #1 Export Policy #1
Routing
Routes Routes
Import Policy #2 Table Export Policy #2
Protocol Protocol
PFE
Forwarding
Table
= Slide 9
Routing Policy
u Poli