Virtual System is Logically chassy inside  JUNOS BOX, its posibility for us to create an topology inside Junos Box .

Below is the step:

Set All Interface to vlan Tagging Mode

set interfaces ge-0/0/1 vlan-tagging
set interfaces ge-0/0/2 vlan-tagging
set interfaces ge-0/0/3 vlan-tagging

## Configure Logical System R1

set logical-systems R1 interfaces ge-0/0/1 unit 12 vlan-id 12
set logical-systems R1 interfaces ge-0/0/1 unit 12 family inet address 12.12.12.1/24
set logical-systems R1 interfaces lo0 unit 1 family inet address 1.1.1.1/32

## Configure Logical System R2

set logical-systems R2 interfaces ge-0/0/1 unit 23 vlan-id 23
set logical-systems R2 interfaces ge-0/0/1 unit 23 family inet address 23.23.23.3/24
set logical-systems R2 interfaces ge-0/0/2 unit 20 vlan-id 12
set logical-systems R2 interfaces ge-0/0/2 unit 20 family inet address 12.12.12.2/24
set logical-systems R2 interfaces lo0 unit 2 family inet address 2.2.2.2/32

## Configure Logical System R3

set logical-systems R3 interfaces ge-0/0/3 unit 23 vlan-id 23
set logical-systems R3 interfaces ge-0/0/3 unit 23 family inet address 23.23.23.2/24
set logical-systems R3 interfaces lo0 unit 3 family inet address 3.3.3.3/32

 

Topology :

 

[R1]—-– vlan12–——-[R2]——–vlan 23–—–[R3]

12.12.12.0/24          23.23.23.0/24