Play time with JunOS BGP !!!

This article will cover e-BGP, i-BGP, Route Advertisement, and Local Preference configuration on JunOS

Network Design

e-BGP configuration

e-BGP on J1 (J2 and J3 can be done accordingly)

set router-id first…

And then set neighborship

i-BGP configuration

i-BGP on J2 (J3 can be done accordingly)

We can see that J2 has 2 groups…1 for i-BGP peers and 1 for e-BGP peers

BGP Neighborship

Lets take a look at BGP Neighborship on J3 after all converges

show bgp summary


BGP Route Advertisement

BGP Route Advertisement on J1 (J2 and J3 can be done accordingly)

Set policy for advertising the routes, for example we want J1 to advertise from its loopback

Then export the policy into BGP group external

Route advertisement verification on J2

Route advertisement on J2 is slightly a little bit different, we export the policy ABOVE the BGP group (right after we set protocol bgp)

So, both internal and external BGP get the routes

Verification on J1

Configuring Path Modification via Local Preference

Accourding to “show route protocol bgp”, we get information that route can be reach via em0.0 (through J2)

Now lets change it…route will be reached via em1.0 (through J3)

Configure local preference on R1

Import the policy into BGP group *screenshot missing…I forgot haha*