Before You Configure Bgp; Configuration Tasks; Basic Configuration; Enabling Bgp Routing - Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual

Before You Configure BGP

Before you attempt to configure BGP, ensure that you have TCP/IP reachability to
the BGP peers with which you want your router to communicate. This may include
tasks such as setting up interfaces and creating routes.
See the JUNOSe Link Layer Configuration Guide and JUNOSe Physical Layer Configuration
Guide for information about how to configure appropriate interfaces. See JUNOSe IP
Services Configuration Guide, for information about setting up routing information.

Configuration Tasks

BGP is a very flexible protocol, often providing more than one way to achieve a
routing goal. The configuration tasks required therefore vary depending on your
needs and decisions. Read all of the following sections to determine the best method
for configuring BGP for your needs.

Basic Configuration

Two tasks are common to every BGP configuration: You must enable the BGP routing
process, and you must configure BGP neighbors. All other basic configuration tasks
are optional.
You can configure certain BGP attributes globally, for peer groups, or for individual
peers. The most specific level of configuration takes precedence. For example, if you
configure an attribute both globally and for a peer group, the peer group configuration
takes precedence for that peer group, but does not affect other peer groups. If you
configure an attribute both for a peer group and for a peer, the peer configuration
takes precedence for that peer, but does not affect other members of that peer group.

Enabling BGP Routing

All BGP configurations require that you enable the BGP routing process on one or
more routers.
router bgp
Use to enable the BGP routing protocol and to specify the local AS the AS to
which this BGP speaker belongs.
All subsequent BGP configuration commands are placed within the context of
this router and AS; you can have only a single BGP instance per virtual router.
Specify only one BGP AS per virtual router.
This command takes effect immediately.
Example
host1(config)#router bgp 100
Chapter 1: Configuring BGP Routing
Before You Configure BGP
17