Interprovider L3VPN Option A on a vMX

Implementation Description

In this article, I will build an Interprovider L3VPN Option A setup on a single vMX. Each individual router will be configured as a logical router. The vMX router has a back-to-back connection between ge-0/0/0 and ge-0/0/1 ports. For each different link, a different VLAN number will be configured to separate the traffic generated based on router ID number.

Network Diagram

IP Allocation

  • AS 20: 192.168.20.0/16
    • CE 21: 192.168.0.21/32
    • CE 22: 192.168.0.22/32
    • Link 1121: 192.168.20.0/31
    • Link 1622: 192.168.20.2/31
  • AS 30: 192.168.30.0/16
    • CE 31: 192.168.0.31/32
    • CE 32: 192.168.0.32/32
    • Link 1131: 192.168.30.0/31
    • Link 1632: 192.168.30.2/31
  • AS 100: 10.100.0.0/16
    • PE 11: 10.100.0.11/32
    • P 12: 10.100.0.12/32
    • ASBR 13: 10.100.0.13/32
    • Internal Links: 10.100.1.0/16
  • AS 200: 10.200.0.0/16
    • PE 16: 10.200.0.16/32
    • P 15: 10.200.0.15/32
    • ASBR 14: 10.200.0.14/32
    • Internal Links: 10.200.1.0/16
  • Inter-ASBR links:
    • Link 20: 172.167.20.0/31
    • LInk 30: 172.167.30.0/31

Full Configuration

## Last changed: 2018-03-06 12:52:17 UTC
version 15.1F4.15;
groups {
    isis {
        logical-systems {
            <*> {
                protocols {
                    isis {
                        level 1 disable;
                        interface <*> {
                            point-to-point;
                        }
                    }
                }
            }
        }
    }
}
apply-groups isis;
system {
    host-name MX;
    root-authentication {
        encrypted-password "$5$L3F31155$kVyagZl2v/WM9s32/hi7VCXxM5o0vupYD.LO3uvCif4"; ## SECRET-DATA
    }
    services {
        ssh;
        netconf {
            ssh;
        }
    }
    syslog {
        user * {
            any emergency;
        }
        file messages {
            any notice;
            authorization info;
        }
        file interactive-commands {
            interactive-commands any;
        }
    }
}
logical-systems {
    11-PE {
        interfaces {
            ge-0/0/0 {
                unit 1112 {
                    vlan-id 1112;
                    family inet {
                        address 10.100.1.0/31;
                    }
                    family iso;
                    family mpls;
                }
                unit 1121 {
                    vlan-id 1121;
                    family inet {
                        address 192.168.20.0/31;
                    }
                }
                unit 1131 {
                    vlan-id 1131;
                    family inet {
                        address 192.168.30.0/31;
                    }
                }
            }
            lo0 {
                unit 11 {
                    family inet {
                        address 10.100.0.11/32;
                    }
                    family iso {
                        address 49.0100.0101.0000.0011.00;
                    }
                }
            }
        }
        protocols {
            mpls {
                interface all;
            }
            bgp {
                group internal {
                    type internal;
                    local-address 10.100.0.11;
                    family inet-vpn {
                        any;
                    }
                    neighbor 10.100.0.13;
                }
            }
            isis {
                interface ge-0/0/0.1112;
                interface lo0.11;
            }
            ldp {
                interface all;
            }
        }
        routing-instances {
            Cust-20 {
                instance-type vrf;
                interface ge-0/0/0.1121;
                route-distinguisher 10.100.0.11:20;
                vrf-target target:100:20;
                protocols {
                    bgp {
                        group to-Cust {
                            type external;
                            peer-as 20;
                            as-override;
                            neighbor 192.168.20.1;
                        }
                    }
                }
            }
            Cust-30 {
                instance-type vrf;
                interface ge-0/0/0.1131;
                route-distinguisher 10.100.0.11:30;
                vrf-target target:100:30;
                protocols {
                    bgp {
                        group to-Cust {
                            type external;
                            peer-as 30;
                            as-override;
                            neighbor 192.168.30.1;
                        }
                    }
                }
            }
        }
        routing-options {
            autonomous-system 100;
        }
    }
    12-P {
        interfaces {
            ge-0/0/0 {
                unit 1213 {
                    vlan-id 1213;
                    family inet {
                        address 10.100.1.2/31;
                    }
                    family iso;
                    family mpls;
                }
            }
            ge-0/0/1 {
                unit 1112 {
                    vlan-id 1112;
                    family inet {
                        address 10.100.1.1/31;
                    }
                    family iso;
                    family mpls;
                }
            }
            lo0 {
                unit 12 {
                    family inet {
                        address 10.100.0.12/32;
                    }
                    family iso {
                        address 49.0100.0101.0000.0012.00;
                    }
                }
            }
        }
        protocols {
            mpls {
                interface all;
            }
            isis {
                interface all;
            }
            ldp {
                interface all;
            }
        }
        routing-options {
            autonomous-system 100;
        }
    }
    13-ASBR {
        interfaces {
            ge-0/0/0 {
                unit 20 {
                    vlan-id 20;
                    family inet {
                        address 172.167.20.0/31;
                    }
                }
                unit 30 {
                    vlan-id 30;
                    family inet {
                        address 172.167.30.0/31;
                    }
                }
            }
            ge-0/0/1 {
                unit 1213 {
                    vlan-id 1213;
                    family inet {
                        address 10.100.1.3/31;
                    }
                    family iso;
                    family mpls;
                }
            }
            lo0 {
                unit 13 {
                    family inet {
                        address 10.100.0.13/32;
                    }
                    family iso {
                        address 49.0100.0101.0000.0013.00;
                    }
                }
            }
        }
        protocols {
            mpls {
                interface all;
            }
            bgp {
                group internal {
                    type internal;
                    local-address 10.100.0.13;
                    family inet-vpn {
                        any;
                    }
                    neighbor 10.100.0.11;
                }
            }
            isis {
                interface all;
            }
            ldp {
                interface all;
            }
        }
        routing-instances {
            Cust-20 {
                instance-type vrf;
                interface ge-0/0/0.20;
                route-distinguisher 10.100.0.13:20;
                vrf-target target:100:20;
                protocols {
                    bgp {
                        group to-AS200 {
                            type external;
                            peer-as 200;
                            neighbor 172.167.20.1;
                        }
                    }
                }
            }
            Cust-30 {
                instance-type vrf;
                interface ge-0/0/0.30;
                route-distinguisher 10.100.0.13:30;
                vrf-target target:100:30;
                protocols {
                    bgp {
                        group to-AS200 {
                            type external;
                            peer-as 200;
                            neighbor 172.167.30.1;
                        }
                    }
                }
            }
        }
        routing-options {
            autonomous-system 100;
        }
    }
    14-ASBR {
        interfaces {
            ge-0/0/0 {
                unit 1415 {
                    vlan-id 1415;
                    family inet {
                        address 10.200.1.4/31;
                    }
                    family iso;
                    family mpls;
                }
            }
            ge-0/0/1 {
                unit 20 {
                    vlan-id 20;
                    family inet {
                        address 172.167.20.1/31;
                    }
                }
                unit 30 {
                    vlan-id 30;
                    family inet {
                        address 172.167.30.1/31;
                    }
                }
            }
            lo0 {
                unit 14 {
                    family inet {
                        address 10.200.0.14/32;
                    }
                    family iso {
                        address 49.0200.0102.0000.0014.00;
                    }
                }
            }
        }
        protocols {
            mpls {
                interface all;
            }
            bgp {
                group internal {
                    type internal;
                    local-address 10.200.0.14;
                    family inet-vpn {
                        any;
                    }
                    neighbor 10.200.0.16;
                }
            }
            isis {
                interface all;
            }
            ldp {
                interface all;
            }
        }
        routing-instances {
            Cust-20 {
                instance-type vrf;
                interface ge-0/0/1.20;
                route-distinguisher 10.200.0.13:20;
                vrf-target target:200:20;
                protocols {
                    bgp {
                        group to-AS100 {
                            type external;
                            peer-as 100;
                            neighbor 172.167.20.0;
                        }
                    }
                }
            }
            Cust-30 {
                instance-type vrf;
                interface ge-0/0/1.30;
                route-distinguisher 10.200.0.14:30;
                vrf-target target:200:30;
                protocols {
                    bgp {
                        group to-AS100 {
                            type external;
                            peer-as 100;
                            neighbor 172.167.30.0;
                        }
                    }
                }
            }
        }
        routing-options {
            autonomous-system 200;
        }
    }
    15-P {
        interfaces {
            ge-0/0/0 {
                unit 1516 {
                    vlan-id 1516;
                    family inet {
                        address 10.200.1.6/31;
                    }
                    family iso;
                    family mpls;
                }
            }
            ge-0/0/1 {
                unit 1415 {
                    vlan-id 1415;
                    family inet {
                        address 10.200.1.5/31;
                    }
                    family iso;
                    family mpls;
                }
            }
            lo0 {
                unit 15 {
                    family inet {
                        address 10.200.0.15/32;
                    }
                    family iso {
                        address 49.0100.0102.0000.0015.00;
                    }
                }
            }
        }
        protocols {
            mpls {
                interface all;
            }
            isis {
                interface all;
            }
            ldp {
                interface all;
            }
        }
    }
    16-PE {
        interfaces {
            ge-0/0/0 {
                unit 1622 {
                    vlan-id 1622;
                    family inet {
                        address 192.168.20.2/31;
                    }
                }
                unit 1632 {
                    vlan-id 1632;
                    family inet {
                        address 192.168.30.2/31;
                    }
                }
            }
            ge-0/0/1 {
                unit 1516 {
                    vlan-id 1516;
                    family inet {
                        address 10.200.1.7/31;
                    }
                    family iso;
                    family mpls;
                }
            }
            lo0 {
                unit 16 {
                    family inet {
                        address 10.200.0.16/32;
                    }
                    family iso {
                        address 49.0200.0102.0000.0016.00;
                    }
                }
            }
        }
        protocols {
            mpls {
                interface all;
            }
            bgp {
                group internal {
                    type internal;
                    local-address 10.200.0.16;
                    family inet-vpn {
                        any;
                    }
                    neighbor 10.200.0.14;
                }
            }
            isis {
                interface all;
            }
            ldp {
                interface all;
            }
        }
        routing-instances {
            Cust-20 {
                instance-type vrf;
                interface ge-0/0/0.1622;
                route-distinguisher 10.100.0.16:20;
                vrf-target target:200:20;
                protocols {
                    bgp {
                        group to-Cust {
                            type external;
                            peer-as 20;
                            as-override;
                            neighbor 192.168.20.3;
                        }
                    }
                }
            }
            Cust-30 {
                instance-type vrf;
                interface ge-0/0/0.1632;
                route-distinguisher 10.100.0.16:30;
                vrf-target target:200:30;
                protocols {
                    bgp {
                        group to-Cust {
                            type external;
                            peer-as 30;
                            as-override;
                            neighbor 192.168.30.3;
                        }
                    }
                }
            }
        }
        routing-options {
            autonomous-system 200;
        }
    }
    21-CE {
        interfaces {
            ge-0/0/1 {
                unit 1121 {
                    vlan-id 1121;
                    family inet {
                        address 192.168.20.1/31;
                    }
                }
            }
            lo0 {
                unit 21 {
                    family inet {
                        address 192.168.0.21/32;
                    }
                }
            }
        }
        protocols {
            bgp {
                group AS100 {
                    type external;
                    export to-bgp;
                    peer-as 100;
                    neighbor 192.168.20.0;
                }
            }
        }
        policy-options {
            policy-statement to-bgp {
                from protocol direct;
                then accept;
            }
        }
        routing-options {
            autonomous-system 20;
        }
    }
    22-CE {
        interfaces {
            ge-0/0/1 {
                unit 1622 {
                    vlan-id 1622;
                    family inet {
                        address 192.168.20.3/31;
                    }
                }
            }
            lo0 {
                unit 22 {
                    family inet {
                        address 192.168.0.22/32;
                    }
                }
            }
        }
        protocols {
            bgp {
                group AS200 {
                    type external;
                    export to-bgp;
                    peer-as 200;
                    neighbor 192.168.20.2;
                }
            }
        }
        policy-options {
            policy-statement to-bgp {
                from protocol direct;
                then accept;
            }
        }
        routing-options {
            autonomous-system 20;
        }
    }
    31-CE {
        interfaces {
            ge-0/0/1 {
                unit 1131 {
                    vlan-id 1131;
                    family inet {
                        address 192.168.30.1/31;
                    }
                }
            }
            lo0 {
                unit 31 {
                    family inet {
                        address 192.168.0.31/32;
                    }
                }
            }
        }
        protocols {
            bgp {
                group AS100 {
                    type external;
                    export to-bgp;
                    peer-as 100;
                    neighbor 192.168.30.0;
                }
            }
        }
        policy-options {
            policy-statement to-bgp {
                from protocol direct;
                then accept;
            }
        }
        routing-options {
            autonomous-system 30;
        }
    }
    32-CE {
        interfaces {
            ge-0/0/1 {
                unit 1632 {
                    vlan-id 1632;
                    family inet {
                        address 192.168.30.3/31;
                    }
                }
            }
            lo0 {
                unit 32 {
                    family inet {
                        address 192.168.0.32/32;
                    }
                }
            }
        }
        protocols {
            bgp {
                group AS200 {
                    type external;
                    export to-bgp;
                    peer-as 200;
                    neighbor 192.168.30.2;
                }
            }
        }
        policy-options {
            policy-statement to-bgp {
                from protocol direct;
                then accept;
            }
        }
        routing-options {
            autonomous-system 30;
        }
    }
}
interfaces {
    ge-0/0/0 {
        description "to ge-0/0/1";
        vlan-tagging;
    }
    ge-0/0/1 {
        description "to ge-0/0/0";
        vlan-tagging;
    }
    ge-0/0/2 {
        description "to ge-0/0/3";
        vlan-tagging;
    }
    ge-0/0/3 {
        description "to ge-0/0/2";
        vlan-tagging;
    }
    ge-0/0/4 {
        description "to ge-0/0/5";
        vlan-tagging;
    }
    ge-0/0/5 {
        description "to ge-0/0/4";
        vlan-tagging;
    }
    ge-0/0/6 {
        description "to ge-0/0/7";
        vlan-tagging;
    }
    ge-0/0/7 {
        description "to ge-0/0/6";
        vlan-tagging;
    }
    ge-0/0/8 {
        description "to eth1";
    }
    ge-0/0/9 {
        description "to eth2";
    }
    fxp0 {
        unit 0 {
            family inet {
                address 192.168.83.11/24;
            }
        }
    }
}

Verification

[edit]
root@MX:21-CE# run show route 

inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

172.167.20.0/31    *[BGP/170] 00:04:04, localpref 100
                      AS path: 100 I, validation-state: unverified
                    > to 192.168.20.0 via ge-0/0/1.1121
192.168.0.21/32    *[Direct/0] 04:10:00
                    > via lo0.21
192.168.0.22/32    *[BGP/170] 00:04:04, localpref 100
                      AS path: 100 200 100 I, validation-state: unverified
                    > to 192.168.20.0 via ge-0/0/1.1121
192.168.20.0/31    *[Direct/0] 04:09:08
                    > via ge-0/0/1.1121
192.168.20.1/32    *[Local/0] 04:09:08
                      Local via ge-0/0/1.1121
192.168.20.2/31    *[BGP/170] 00:04:04, localpref 100
                      AS path: 100 200 I, validation-state: unverified
                    > to 192.168.20.0 via ge-0/0/1.1121

[edit]
root@MX:21-CE# run ping 192.168.0.22 count 3 source 192.168.0.21 
PING 192.168.0.22 (192.168.0.22): 56 data bytes
64 bytes from 192.168.0.22: icmp_seq=0 ttl=52 time=9.114 ms
64 bytes from 192.168.0.22: icmp_seq=1 ttl=52 time=10.155 ms
64 bytes from 192.168.0.22: icmp_seq=2 ttl=52 time=8.088 ms

--- 192.168.0.22 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max/stddev = 8.088/9.119/10.155/0.844 ms

Label Operation


1. Customer router will send simple traffic.

root@MX:21-CE> show route 192.168.0.22 

inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.0.22/32    *[BGP/170] 00:10:08, localpref 100
                      AS path: 100 200 100 I, validation-state: unverified
                    > to 192.168.20.0 via ge-0/0/1.1121

2. Router 11-PE will add two labels to the traffic, L3VPN label and LDP transport label.

root@MX:11-PE> show route 192.168.0.22 

Cust-20.inet.0: 6 destinations, 7 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.0.22/32    *[BGP/170] 00:11:04, localpref 100, from 10.100.0.13
                      AS path: 200 20 I, validation-state: unverified
                    > to 10.100.1.1 via ge-0/0/0.1112, Push 299808, Push 299792(top)

3. Router 12-P is PHP and will pop the LDP label.

root@MX:12-P> show route 192.168.0.22 

root@MX:12-P> show route label 299792 

mpls.0: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

299792             *[LDP/9] 02:34:46, metric 1
                    > to 10.100.1.3 via ge-0/0/0.1213, Pop      
299792(S=0)        *[LDP/9] 02:34:46, metric 1
                    > to 10.100.1.3 via ge-0/0/0.1213, Pop

4. Router 13-ASBR will pop L3VPN label and will forward simple traffic on the dedicated circuit.

root@MX:13-ASBR> show route 192.168.0.22 

Cust-20.inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.0.22/32    *[BGP/170] 00:14:39, localpref 100
                      AS path: 200 20 I, validation-state

5. Router 14-ASBR will add two labels to the traffic, L3VPN label and LDP transport label.

root@MX:14-ASBR> show route 192.168.0.22 

Cust-20.inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.0.22/32    *[BGP/170] 00:16:04, localpref 100, from 10.200.0.16
                      AS path: 20 I, validation-state: unverified
                    > to 10.200.1.5 via ge-0/0/0.1415, Push 299808, Push 299792(top)

6. Router 15-P is PHP and will pop the LDP label.

root@MX:15-P> show route 192.168.0.22 

root@MX:15-P> show route label 299792 

mpls.0: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

299792             *[LDP/9] 00:23:26, metric 1
                    > to 10.200.1.7 via ge-0/0/0.1516, Pop      
299792(S=0)        *[LDP/9] 00:23:26, metric 1
                    > to 10.200.1.7 via ge-0/0/0.1516, Pop

7. Router 16-PE will pop L3VPN label and will forward simple traffic to the end customer.

root@MX:16-PE> show route 192.168.0.22 

Cust-20.inet.0: 6 destinations, 7 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.0.22/32    *[BGP/170] 00:19:35, localpref 100
                      AS path: 20 I, validation-state: unverified
                    > to 192.168.20.3 via ge-0/0/0.1622

The Factors that Limit the Scalability of this Method

  • All inter-AS VPN routes (potentially a very large number) must be stored in the BGP RIBs and IP routing tables on the AS boundary routers.
  • You must configure VRFs on each AS boundary router.

Sources:

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