This example provides a step-by-step procedure and commands for configuring and verifying a Layer 2 circuit to a Layer 2 VPN. It contains the following sections:

• Requirements
• Overview and Topology
• Configuration

This example uses the following hardware and software components:

Figure 1: Physical Topology of a Layer 2 Circuit to a Layer 2 VPN Connection

Figure 2: Logical Topology of a Layer 2 Circuit to a Layer 2 VPN Connection

In this example, the router being configured is identified using the following command prompts:

In this example, all of the PE routers and P routers are configured with OSPF as the IGP protocol. The MPLS, LDP, and BGP protocols are enabled on all of the interfaces except fxp.0. Core-facing interfaces are enabled with the MPLS address and inet address.

1. On Router PE1, configure the ge-1/0/0 interface encapsulation. To configure the interface encapsulation, include the encapsulation statement and specify the ethernet-ccc option (vlan-ccc encapsulation is also supported). Configure the ge-1/0/0.0 logical interface family for circuit cross-connect functionality. To configure the logical interface family, include the family statement and specify the ccc option. The encapsulation should be configured the same way for all routers in the Layer 2 circuit domain.
   [edit interfaces]

   ge-1/0/0 {encapsulation ethernet-ccc;unit 0 {family ccc;}}

   lo0 {unit 0 {family inet {address 1.1.1.1/32;}}}
2. Router PE5 is the router that is stitching the Layer 2 circuit to the Layer 2 VPN using the interworking interface. The configuration of the peer unit interfaces is what makes the interconnection.

   On Router PE5, configure the iw0 interface with two logical interfaces. To configure the iw0 interface, include the interfaces statement and specify iw0 as the interface name. For the unit 0 logical interface, include the peer-unit statement and specify the logical interface unit 1 as the peer interface. For the unit 1 logical interface, include the peer-unit statement and specify the logical interface unit 0 as the peer interface.

   [edit interfaces]

   iw0 {unit 0 {encapsulation ethernet-ccc;peer-unit 1;}unit 1 {encapsulation ethernet-ccc;peer-unit 0;}}
3. On Router PE5, configure the logical loopback interface. The loopback interface is used to establish the targeted LDP sessions to Routers PE1 and PE5.
   [edit interfaces]

   lo0 {unit 0 {family inet {address 5.5.5.5/32;}}}

Step-by-Step Procedure

1. On Router PE1, configure the IP address of the remote PE router with the neighbor statement. The loopback address and router ID of the PE neighbor is commonly the neighbor’s IP address. To allow a Layer 2 circuit to be established even though the maximum transmission unit (MTU) configured on the PE router does not match the MTU configured on the remote PE router, include the ignore-mtu-mismatch statement.
   [edit]

   protocols {l2circuit {neighbor 5.5.5.5 {interface ge-1/0/0.0 {virtual-circuit-id 100;no-control-word;ignore-mtu-mismatch;}}}}
2. On Router PE5, configure the IP address of the remote PE router. To configure the IP address of the remote PE router, include the neighbor statement and specify the IP address of the loopback interface on Router PE1. Configure the virtual circuit ID to be the same as the virtual circuit ID on the neighbor router. To allow a Layer 2 circuit to be established even though the MTU configured on the local PE router does not match the MTU configured on the remote PE router, include the ignore-mtu-mismatch statement. Also disable the use of the control word for demultiplexing by including the no-control-word statement.
   [edit protocols]

   l2circuit {neighbor 1.1.1.1 {interface iw0.0 {virtual-circuit-id 100;no-control-word;ignore-mtu-mismatch;}}}
3. On Router PE5, configure the Layer 2 VPN protocols by including the l2vpn statement at the [edit routing-instances routing-instances-name protocols] hierarchy level. To configure the iw0 interface, include the interfaces statement and specify iw0 as the interface name. The iw0 interface is configured under the Layer 2 VPN protocols to receive the looped packet from the iw0.1 logical interface. The l2vpn protocol is configured on Router PE5 with site CE5, which is configured in the BGP L2VPN routing instance. Router CE1 has communication to Router CE5, through the Layer 2 interworking configuration on Router PE5.
   [edit]

   routing-instances {L2VPN {instance-type l2vpn;interface ge-2/0/0.0;interface iw0.1;route-distinguisher 65000:5;vrf-target target:65000:2;protocols {l2vpn {encapsulation-type ethernet;site CE5 {site-identifier 5;interface ge-2/0/0.0 {remote-site-id 3;}}site l2-circuit {site-identifier 6;interface iw0.1 {remote-site-id 3;}}}}}}
4. In addition to the iw0 interface configuration, the Layer 2 interworking l2iw protocol must be configured. Without the l2iw protocol configuration, the Layer 2 interworking routes are not formed, regardless of whether any iw interfaces are present.

   On Router PE5, configure the l2iw protocol. To configure the protocol, include the l2iw statement at the [edit protocols] hierarchy level.

   [edit]

   protocols {l2iw;}

Verification

Step-by-Step Procedure

1. On Router PE1, use the show l2circuit connections command to verify that the Layer 2 Circuit from Router PE1 to Router PE5 is Up.
   user@PE1> show l2circuit connections

   Layer-2 Circuit Connections:
   Legend for connection status (St)   
   EI -- encapsulation invalid      NP -- interface h/w not present   
   MM -- mtu mismatch               Dn -- down                       
   EM -- encapsulation mismatch     VC-Dn -- Virtual circuit Down    
   CM -- control-word mismatch      Up -- operational                
   VM -- vlan id mismatch           CF -- Call admission control failure
   OL -- no outgoing label          IB -- TDM incompatible bitrate 
   NC -- intf encaps not CCC/TCC    TM -- TDM misconfiguration 
   BK -- Backup Connection          ST -- Standby Connection
   CB -- rcvd cell-bundle size bad  XX -- unknown
   SP -- Static Pseudowire
   
   Legend for interface status  
   Up -- operational            
   Dn -- down                   
   Neighbor: 5.5.5.5 
       Interface                 Type  St     Time last up   # Up trans
       ge-1/0/0.0(vc 100)        rmt   Up     Jan  3 22:00:49 2010    1
         Remote PE: 5.5.5.5, Negotiated control-word: No
         Incoming label: 301328, Outgoing label: 300192
         Local interface: ge-1/0/0.0, Status: Up, Encapsulation: ETHERNET
   

2. On Router PE5, use the show l2vpn connections command to verify that the Layer 2 VPN connection is Up using the iw0 peer interface of the Layer 2 circuit.
   user@PE5> show l2vpn connections

   Instance: L2VPN
     Local site: CE5 (5)
       connection-site           Type  St     Time last up     # Up trans
       l2-circuit (6)            loc   OR   
       3                         rmt   Up
        Jan  3 22:51:12 2010           1
         Remote PE: 3.3.3.3, Negotiated control-word: Yes (Null)
         Incoming label: 800258, Outgoing label: 800000
         Local interface: ge-2/0/0.0, Status: Up, Encapsulation: ETHERNET
     Local site: l2-circuit (6)
       connection-site           Type  St     Time last up    # Up trans
       CE5 (5)                   loc   OR   
       3                         rmt   Up     Jan  3 22:56:38 2010    1
         Remote PE: 3.3.3.3, Negotiated control-word: Yes (Null)
         Incoming label: 800262, Outgoing label: 800001
         Local interface: iw0.1, Status: Up, Encapsulation: ETHERNET
   
   

Step-by-Step Procedure

1. On Router PE5, use the show l2circuit connections command to verify that the Layer 2 circuit is Up using the iw0 interface. This will be looped through the iwo.1 interface to the Layer 2 VPN.
   user@PE5> show l2circuit connections

      
   Layer-2 Circuit Connections:
   Neighbor: 1.1.1.1 
       Interface            Type  St     Time last up  # Up trans
       iw0.0(vc 100)  rmt   Up Jan  3 21:59:07 2010   1
         Remote PE: 1.1.1.1, Negotiated control-word: No
         Incoming label: 300192, Outgoing label: 301328
   

2. On Router PE 5, use the show route table mpls.0 command to verify the Layer 2 circuit and Layer 2 VPN routes. In the example below, the Layer 2 circuit is associated with LDP label 301328 and the Layer 2 VPN is associated with LDP label 800001. Notice the two iw0 interfaces that are used for the Layer 2 interworking route.
   user@PE5>show route table mpls.0

     
   mpls.0: 18 destinations, 20 routes (18 active, 2 holddown, 0 hidden)
   + = Active Route, - = Last Active, * = Both
   
   0                  *[MPLS/0] 5d 20:07:31, metric 1
                         Receive
   1                  *[MPLS/0] 5d 20:07:31, metric 1
                         Receive
   2                  *[MPLS/0] 5d 20:07:31, metric 1
                         Receive
   299776             *[LDP/9] 2d 03:00:51, metric 1
   300048             *[LDP/9] 2d 03:00:49, metric 1
                       > to 10.10.6.1 via xe-0/1/0.0, Pop      
   300048(S=0)        *[LDP/9] 2d 03:00:49, metric 1
                       > to 10.10.6.1 via xe-0/1/0.0, Pop      
   300192             *[L2IW/6] 19:11:05, metric2 1
                       > to 10.10.6.1 via xe-0/1/0.0, Swap 800001
                       [L2CKT/7] 20:08:36
                       > via iw0.0, Pop      
   800258             *[L2VPN/7] 19:16:31
                       > via ge-2/0/0.0, Pop       Offset: 4
   800262             *[L2IW/6] 19:11:05, metric2 1                       > to 10.10.3.1 via xe-1/1/0.0, Swap 301328                     [L2VPN/7] 19:11:05                     > via iw0.1, Pop       Offset: 4ge-2/0/0.0         *[L2VPN/7] 19:16:31, metric2 1
                       > to 10.10.6.1 via xe-0/1/0.0, Push 800000 Offset: -4
   iw0.0              *[L2CKT/7] 20:08:36, metric2 1
                       > to 10.10.3.1 via xe-1/1/0.0, Push 301328
   iw0.1              *[L2VPN/7] 19:11:05, metric2 1
                       > to 10.10.6.1 via xe-0/1/0.0, Push 800001 Offset: -4