Sample Configuration of eBGP and iBGP(Border Gateway Protocol) on EX series switches

This article provides the configuration eBGP(External BGP) and iBGP(Internal BGP) on EX series switches
Topology:

Switch A-(ge-0/0/0)--------(ge-0/0/0) Switch B-(ge-0/0/1)----------(ge-0/0/1)-Switch C-(ge-0/0/2)------------(ge-0/0/2)-Switch D

                     iBGP & OSPF                                                eBGP                                                               OSPF

Setup:

Switch A :
Lo0 - 100.1.1.1
Ge-0/0/0 – 110.1.1.1/24

Switch B:
Lo0 – 150.1.1.1
Ge-0/0/0 – 110.1.1.2/24
Ge-0/0/1 – 120.1.1.1/24

Switch C:
Lo0 – 200.1.1.1
Ge-0/0/1-120.1.1.2/24
Ge-0/0/2 – 130.1.1.1/24

Switch D:
Lo0 – 210.1.1.1
Ge-0/0/2 – 130.1.1.2/24

The following is the configuration on all the four switches:

Switch 1:

{master:0}[edit ]
[email protected]# show policy-options
policy-statement ospf {
      term t1 {
          from protocol [ direct local ];
          then accept;
      }
}


{master:0}[edit ]
[email protected]# show protocols ospf
export ospf;
area 0.0.0.0 {
      interface ge-0/0/0.0;
}

{master:0}[edit ]
[email protected]# show routing-options
autonomous-system 1000;

{master:0}[edit ]
[email protected]# show protocols bgp
local-as 1000;
group iBGP {
         type internal;
         local-address 100.1.1.1;
         neighbor 150.1.1.1 {
             peer-as 1000;
         }
}

Switch 2:

{master:0}[edit ]
[email protected]# show policy-options
policy-statement bgp {
      term t1 {
            from protocol bgp;
            then {
              next-hop self;
              accept;
           }
      }
}
policy-statement bgp1 {
   term t2 {
        from {
            route-filter 120.1.1.0/24 exact;
            route-filter 150.1.1.1/32 exact;
        }
        then reject;
    }
    term t1 { 
       from protocol [ ospf direct local ];
       then {
             tag add 100;
             accept;
       }
   }
}
policy-statement ospf {
     term t1 {
        from protocol [ local direct static ];
        then accept;
     }
}

{master:0}[edit ]
[email protected]# show protocols bgp
local-as 1000;
group eBGP {
    type external;
    local-address 150.1.1.1;
    export bgp1;
    neighbor 200.1.1.1 {
         multihop {
              ttl 2;
         }
         peer-as 2000;        
     }
}
group iBGP {
    type internal;
    local-address 150.1.1.1;
    export bgp;
    neighbor 100.1.1.1 {
             peer-as 1000;
    }
}

{master:0}[edit ]
[email protected]# show  routing-options
static {
          route 200.1.1.1/32 next-hop 120.1.1.2;
}
autonomous-system 1000;

Switch 3:

{master:0}[edit ]
[email protected]# show policy-options
policy-statement bgp {
   term t2 {
     from {
              route-filter 120.1.1.0/24 exact;
              route-filter 200.1.1.1/32 exact;
    }
    then reject;
  }
  term t1 {
            from protocol [ ospf direct local ];
            then accept;
   }
}
policy-statement ospf {
          term t1 {
               from protocol [ direct local bgp static ];
               then {
                    tag2 add 1000;
                    accept;
               }
         }
}

{master:0}[edit ]
[email protected]# show protocols bgp
local-as 2000;
group eBGP {
         type external;
         local-address 200.1.1.1;
         export bgp;
         neighbor 150.1.1.1 {
                 multihop {
                 ttl 2;
         }
         peer-as 1000;
    }
}

{master:0}[edit ]
[email protected]# show routing-options
static {
       route 150.1.1.1/32 next-hop 120.1.1.1;
}
autonomous-system 2000;

Switch 4:

{master:0}[edit ]
[email protected]# show policy-options
policy-statement ospf {
    term t1 {
          from protocol [ ospf direct local ];
          then accept;
    }
}

{master:0}[edit ]
[email protected]# show protocols ospf
export ospf;
area 0.0.0.0 {
           interface ge-0/0/2.0;
}

{master:0}[edit ]
[email protected]# show routing-options
autonomous-system 2000;