Configure eBGP Neighborship in Junos

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

[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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