Configure eBGP Neighborship in Junos

Google ADs

To configure BGP peer session on “A” Router. This document will help understand eBGP configuration across 2 Junos enabled BGP Routers in different AS.

Example Scenario: eBGP Neighborship in Junos

Below is the diagram showing connectivity between devices, their IP address and AS number each belongs to –

To Configure the BGP Peer Session on “HUB” Router –

Step 1

Configure the interface to Peers A

[edit interfaces]user@HUB# set ge-1/2/0 unit 0 description to-A
user@HUB# set ge-1/2/0 unit 0 family inet address 192.168.1.1/30

Step 2

Set the autonomous system (AS) number

Google ADs

[edit interfaces]user@HUB# set autonomous-system 1

Step 3

Create the BGP group, and add the external neighbor addresses.

[edit protocols bgp group external-peers]user@HUB# set neighbor 192.168.1.2

Step 4

Specify the autonomous system (AS) number of the external AS.

[edit protocols bgp group external-peers]user@HUB# set peer-as 2

Step 5

Set the peer type to external BGP (EBGP)

[edit protocols bgp group external-peers]user@HUB# set type external

To Configure the BGP Peer Session on “A” Router –

Step 6

Configure the interface to Peer HUB

[edit interfaces]user@A# set ge-1/2/0 unit 0 description to-HUB
user@A# set ge-1/2/0 unit 0 family inet address 192.168.1.2/30

Step 7

Set the autonomous system (AS) number.

[edit routing-options]user@A# set autonomous-system 2

Step 8

Create the BGP group, and add the external neighbor addresses.

[edit protocols bgp group external-peers]user@A# set neighbor 192.168.1.1

Step 9

Specify the autonomous system (AS) number of the external AS.

[edit protocols bgp group external-peers]user@A# set peer-as 1

Step 10

Set the peer type to external BGP (EBGP).

[edit protocols bgp group external-peers]user@A# set type external

Verification

From configuration mode, confirm your configuration by entering the show interfaces, show protocols, and show routing-options commands.

Some of BGP status and neighborship command include –

show bgp neighbor
show bgp group

Additionally “Show BGP Summary” command output also provides information in addition to BGP neighorship –

user@HUB> show bgp summary
Groups: 1      Peers: 1      Down peers: 0
Table          Tot Paths Act Paths Suppressed    History    Damp State    Pending
inet.0                 0          0                       0                     0              0                       0Peer                     AS      InPkt     OutPkt    OutQ   Flaps Last Up/Dwn         State|#Active/Received/Accepted/Damped…
192.168.1.2         22       8559       8470       0             0       2d   17:11:36          0/0/0/0

Continue Reading:

What is eBGP Multihop In BGP?

eBGP vs iBGP: Know the difference between eBGP and iBGP

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ABOUT THE AUTHOR

Rashmi Bhardwaj

Founder of AAR TECHNOSOLUTIONS, Rashmi is an evangelist for IT and technology. With more than 12 years in the IT ecosystem, she has been supporting multi domain functions across IT & consultancy services, in addition to Technical content making.

You can learn more about her on her linkedin profile – Rashmi Bhardwaj