Configuring Peer Policy on ISP Router 3

On ISP Router 3, a separate policy is in place for each customer. The default route for Customer 1 is being sent by the customer-1-peer policy. This policy finds the 0.0.0.0/0 default route in inet.0 and accepts it. The policy also rejects all other routes, thereby not sending all BGP routes on the ISP Router. The customer-2-peer policy is for Customer 2 and contains the same policy terms, which also send the default route and no other transit BGP routes. The additional terms in the customer-2-peer policy send the ISP customer routes to Customer 2. Because there are local static routes on ISP Router 3 that represent local customers, these routes are sent as well as all other internal (192.168.0/17) routes announced to the local router by the other ISP routers.

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routing-options {

    static {                                                                 # simulate local customer routes

        route 192.168.72.0/22 reject;

        route 192.168.76.0/22 reject;

        route 192.168.80.0/22 reject;

        route 192.168.84.0/22 reject;

        route 192.168.88.0/22 reject;

        route 192.168.92.0/22 reject;

        route 192.168.72.0/21 reject;

        route 192.168.80.0/21 reject;

        route 192.168.88.0/21 reject;

    } 

    generate {                                             # install a default route if certain routes

                                                # from the Exchange Peers are advertised using BGP

        route 0.0.0.0/0 policy if-upstream-routes-exist;

    }

    autonomous-system 1000;

}

protocols {

    bgp {

        group Internal-Peers {

            type internal;

            local-address 192.168.0.3;

            export internal-peers;

            neighbor 192.168.0.1;

            neighbor 192.168.0.2;

        }

        group Customer-2 {

            type external;

            export customer-2-peer;

            peer-as 2468;

            neighbor 10.222.61.2;

        }

        group Customer-1 {

            type external;

            export customer-1-peer;

            peer-as 1234;

            neighbor 10.222.70.1;

        }

    }

    isis {

        level 1 disable;

        interface so-0/0/0.0;

        interface ge-0/1/0.0;

        interface lo0.0;

    }

}

policy-options {

    policy-statement internal-peers {                                                                 # advertise local customer routes to peers

        term statics {

            from protocol static;

            then accept;

        } 

        term next-hop-self {                                                                 # set the BGP next hop to Self for EBGP

            then {                                                            # routes advertised to IBGP peers 

                next-hop self;

            }

        }

    }

    policy-statement if-upstream-routes-exist {

        term only-certain-contributing-routes {

            from {                                         # allow either the 10.100/17 or the 10.101.0.0/27 

                route-filter 10.100.0.0/17 exact;                                                            #route to activate the generated route

                route-filter 10.101.0.0/17 exact;

            }

            then accept;

        }                                                            # do not allow any other route to activate

                                                                    # the generated route in the routing table

        term reject-all-other-routes { 

            then reject;

        }

    }

    policy-statement customer-2-peer {                                                                 # advertise customer routes to all peers

        term statics {

            from protocol static;

            then accept;

        } 

        term isp-and-customer-routes {                                                            # advertise internal AS 1000 customer 

            from {                                                        #to the customer

                protocol bgp;

                route-filter 192.168.0.0/17 orlonger;

            }

            then accept;

        }                                                         # advertise just the default route to AS 2468

        term default-route {

            from {

                route-filter 0.0.0.0/0 exact;

            }

            then accept;

        }

        term reject-all-other-routes {                                                                 # do not advertise any other routes 

            then reject;

        }

    }

    policy-statement customer-1-peer { 

        term default-route {                                                         # advertise just the default route to AS 1234

            from {

                route-filter 0.0.0.0/0 exact;

            }

            then accept;

        } 

        term reject-all-other-routes {                                                                 # do not advertise any other routes

            then reject;

        }

    }

}