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Example: Building a VPLS From Router 1 to Router 3

This example illustrates how VPLS label blocks are allocated for a specific configuration. It is organized in the following sections:

Requirements

This configuration example requires three Juniper Networks routers.

Overview and Topology

In the network shown in Figure 1 Router 1 is establishing a pseudowire to Router 3

Figure 1: Router 1 to Router 3 Topology

Image g040505.gif

Each PE filters the VPLS NLRI contained in the BGP update messages based on route target communities. Those VPLS NLRI instances that match the route target (in this case 8717:2000:2:1) are imported for further processing. The NLRI for Router 1 and Router 3 is shown in Table 1.

Table 1: NLRI Exchange Between for Router 1 and Router 3

Router 1 NLRI Advertisement to Router 3

Router 3 NLRI Advertisement to Router 1

RD - 8717:1000

RD - 8717:1000

VE ID - 1

VE ID - 2

VE Block Offset - 1

VE Block Offset - 1

VE Block Size - 8

VE Block Size - 8

Label Base - 262161

Label Base - 262153

To set up a pseudowire to Router 3, Router 1 must select a label to use to send traffic to Router 3 and also select a label that it expects Router 3 to use to send traffic to itself. The site ID contained in the VPLS NLRI from Router 3 is 2.

Router 1 learns of the existence of site ID 2 in the same VPLS domain. Using the equation VBO <= Local Site ID < (VBO +VBS), Router 1 checks if the route advertised by site ID 2 fits in the label block and block offset that it previously advertised to Router 3. In this example it does fit, so the site ID 2 is mapped by the VPLS NLRI advertised by Router 1, and Router 1 is ready to set up a pseudowire to Router 3.

To select the label to reach Router 3, Router 1 looks at the label block advertised by Router 3 and performs a calculation. The calculation a PE router uses to check if its site ID is mapped in the label block from the remote peer is VBO <= Local Site ID < (VBO +VBS). So, Router 1 selects label (262153 + (1 -1)) = 262153 to send traffic to Router 3. Using the same equation, Router 1 looks at its own label block that it advertised and selects label (262161 + (2 - 1)) = 262162 to receive traffic from Router 3. Router 1 programs its forwarding state such that any traffic destined to Router 3 carries the pseudowire label 262153 and any traffic coming from Router 3 is expected to have the pseudowire label 262162. This completes the operations on the VPLS NLRI received from Router 3. Router 1 now has a pseudowire set up to Router 3.

Router 3 operation is very similar to the Router 1 operation. Since the Router 3 site ID of 2 fits in the label block and block offset advertised by Router 1, Router 3 selects label (262161 + (2 - 1)) = 262162 to send traffic to Router 1. Router 3 looks at its own label block that it advertised and selects label (262153 + (1 - 1)) = 262153 to receive traffic from Router 1. This completes the creation of a pseudowire to Router 1.

By default, for VPLS operation JUNOS Software uses a virtual tunnel (VT) loopback interface to represent a pseudowire. This example uses a label-switched interface (LSI) instead of a VT interface because there is no change in the VPLS control plane operation. Thus, for an MX platform, if there is a tunnel physical interface card (PIC) configured, it is mandatory to include the no-tunnel-services statement at the
[edit routing-instances routing-instance-name protocols vpls] hierarchy level.

Configuration

The following sections present the steps to configure and verify the example in Figure 1.

Configuring Router 1

Step-by-Step Procedure

  1. Configure Router 1. Create the edut routing instance. Specify the vpls instance type. Configure the route distinguisher and specify the value 8717:1000. Configure the route target and specify the value 8717:100 Configure the VPLS protocol. Specify 10 as the site range. Specify 1 as the site ID. Include the no-tunnel-services statement.
    [edit routing-instances]edut {instance-type vpls;interface ge-5/0/2.0;route-distinguisher 8717:1000;vrf-target target:8717:100;protocols {vpls {site-range 10;no-tunnel-services;site router-1 {site-identifier 1;}}}}

Configuring Router 3

Step-by-Step Procedure

  1. Configure Router 3. Create the edut routing instance. Specify the vpls instance type. Configure the route distinguisher and specify the value 8717:2000. Configure the route target and specify the value 8717:200 Configure the VPLS protocol. Specify 10 as the site range. Specify 2 as the site ID. Include the no-tunnel-services statement.
    [edit routing-instances]edut {instance-type vpls;interface ge-4/0/2.0;route-distinguisher 8717:2000;vrf-target target:8717:100;protocols {vpls {site-range 10;no-tunnel-services;site router-3 {site-identifier 2;}}}}

Verifying the VPLS Label Allocations

Step-by-Step Procedure

  1. As shown in the figure and the configuration, Site A is attached to Router 1. Site A is assigned a site ID of 1. Before Router 1 can announce its membership to VPLS edut using a BGP update message, Router 1 needs to allocate a default label block. In this example, the label base of the label block allocated by Router 1 is 262161. Since Router 1’s site ID is 1, Router 1 associates the assigned label block with block offset of 1. The following messages aresent from Router 1 to Router 3 and displayed using the monitor traffic interface interface-name command:

    user@Router1> monitor traffic interface ge-5/3/2
    Jun 14 12:26:31.280818 BGP SEND 10.10.10.1+179 -> 10.10.10.3+53950
    Jun 14 12:26:31.280824 BGP SEND message type 2 (Update) length 88
    Jun 14 12:26:31.280828 BGP SEND flags 0x40 code Origin(1): IGP
    Jun 14 12:26:31.280833 BGP SEND flags 0x40 code ASPath(2) length 0: <null>
    Jun 14 12:26:31.280837 BGP SEND flags 0x40 code LocalPref(5): 100
    Jun 14 12:26:31.280844 BGP SEND flags 0xc0 code Extended Communities(16): 2:8717:100 800a:19:0:0
    Jun 14 12:26:31.280848 BGP SEND flags 0x90 code MP_reach(14): AFI/SAFI 25/65
    Jun 14 12:26:31.280853 BGP SEND         nhop 10.10.10.1 len 4
    Jun 14 12:26:31.280862 BGP SEND         8717:1000:1:1 (label base : 262161 range : 8, ce id: 1, offset: 1)  
    Jun 14 12:26:31.405067 BGP RECV 10.10.10.3+53950 -> 10.10.10.1+179
    Jun 14 12:26:31.405074 BGP RECV message type 2 (Update) length 88
    Jun 14 12:26:31.405080 BGP RECV flags 0x40 code Origin(1): IGP
    Jun 14 12:26:31.405085 BGP RECV flags 0x40 code ASPath(2) length 0: <null>
    Jun 14 12:26:31.405089 BGP RECV flags 0x40 code LocalPref(5): 100
    Jun 14 12:26:31.405096 BGP RECV flags 0xc0 code Extended Communities(16): 2:8717:100 800a:19:0:0
    Jun 14 12:26:31.405101 BGP RECV flags 0x90 code MP_reach(14): AFI/SAFI 25/65
    Jun 14 12:26:31.405106 BGP RECV         nhop 10.10.10.3 len 4
    Jun 14 12:26:31.405116 BGP RECV         8717:2000:2:1 (label base : 262153 range : 8, ce id: 2, offset: 1)
    
  2. As shown in the figure and the configuration, Site B is attached to Router 3. Site B is assigned a site ID of 2. Before Router 3 can announce its membership to VPLS edut using a BGP update message, Router 3 assigns a default label block with the label base of 262153. The block offset for this label block is 1 because its own site ID of 2 fits in the block being advertised. The following messages are sent from Router 3 to Router 1 and displayed using the monitor traffic interface interface-name command:

    user@Router3> monitor traffic interface ge-2/0/1
    Jun 14 12:26:31.282008 BGP SEND 10.10.10.3+53950 -> 10.10.10.1+179
    Jun 14 12:26:31.282018 BGP SEND message type 2 (Update) length 88
    Jun 14 12:26:31.282026 BGP SEND flags 0x40 code Origin(1): IGP
    Jun 14 12:26:31.282034 BGP SEND flags 0x40 code ASPath(2) length 0: <null>
    Jun 14 12:26:31.282041 BGP SEND flags 0x40 code LocalPref(5): 100
    Jun 14 12:26:31.282052 BGP SEND flags 0xc0 code Extended Communities(16): 2:8717:100 800a:19:0:0
    Jun 14 12:26:31.282078 BGP SEND flags 0x90 code MP_reach(14): AFI/SAFI 25/65
    Jun 14 12:26:31.282088 BGP SEND         nhop 10.10.10.3 len 4
    Jun 14 12:26:31.282102 BGP SEND         8717:2000:2:1 (label base : 262153 range : 8, ce id: 2, offset: 1)
    
    Jun 14 12:26:31.283395 BGP RECV 10.10.10.1+179 -> 10.10.10.3+53950
    Jun 14 12:26:31.283405 BGP RECV message type 2 (Update) length 88
    Jun 14 12:26:31.283412 BGP RECV flags 0x40 code Origin(1): IGP
    Jun 14 12:26:31.283419 BGP RECV flags 0x40 code ASPath(2) length 0: <null>
    Jun 14 12:26:31.283426 BGP RECV flags 0x40 code LocalPref(5): 100
    Jun 14 12:26:31.283435 BGP RECV flags 0xc0 code Extended Communities(16): 2:8717:100 800a:19:0:0
    Jun 14 12:26:31.283443 BGP RECV flags 0x90 code MP_reach(14): AFI/SAFI 25/65
    Jun 14 12:26:31.283471 BGP RECV         nhop 10.10.10.1 len 4
    Jun 14 12:26:31.283486 BGP RECV         8717:1000:1:1 (label base : 262161 range : 8, ce id: 1, offset: 1)
    
  3. Verify the connection status messages for Router 1 using the show vpls connections command. Notice the base label is 262161, the incoming label from Router 3 is 262162, and the outgoing label to Router 3 is 262153.

    user@Router1> show vpls connections instance edut extensive
    Instance: edut
      Local site: router-1 (1)
        Number of local interfaces: 1
        Number of local interfaces up: 1
        IRB interface present: no
        ge-5/0/2.0         
        lsi.1049600         2         Intf - vpls edut local site 1 remote site 2
        Label-base        Offset     Range     Preference
        262161            1          8         100   
        connection-site           Type  St     Time last up          # Up trans
        2                         rmt   Up     Jun 14 12:26:31 2009           1
          Remote PE: 10.10.10.3, Negotiated control-word: No
          Incoming label: 262162, Outgoing label: 262153
          Local interface: lsi.1049600, Status: Up, Encapsulation: VPLS
            Description: Intf - vpls edut local site 1 remote site 2
        Connection History:
            Jun 14 12:26:31 2009  status update timer  
            Jun 14 12:26:31 2009  loc intf up                  lsi.1049600
            Jun 14 12:26:31 2009  PE route changed     
            Jun 14 12:26:31 2009  Out lbl Update                    262153
            Jun 14 12:26:31 2009  In lbl Update                     262162
            Jun 14 12:26:31 2009  loc intf down
    
    Layer-2 VPN connections:
    
    Legend for connection status (St)   
    EI -- encapsulation invalid      NC -- interface encapsulation not CCC/TCC/VPLS
    EM -- encapsulation mismatch     WE -- interface and instance encaps not same
    VC-Dn -- Virtual circuit down    NP -- interface hardware not present 
    CM -- control-word mismatch      -< -- only outbound connection is up
    CN -- circuit not provisioned    >- -- only inbound connection is up
    OR -- out of range               Up -- operational
    OL -- no outgoing label          Dn -- down                      
    LD -- local site signaled down   CF -- call admission control failure      
    RD -- remote site signaled down  SC -- local and remote site ID collision
    LN -- local site not designated  LM -- local site ID not minimum designated
    RN -- remote site not designated RM -- remote site ID not minimum designated
    XX -- unknown connection status  IL -- no incoming label
    MM -- MTU mismatch               MI -- Mesh-Group ID not availble
    BK -- Backup connection          ST -- Standby connection
    PF -- Profile parse failure      PB -- Profile busy
    
    Legend for interface status 
    Up -- operational           
    Dn -- down
    
  4. Verify the connection status messages for Router 3 using the show vpls connections command. Notice the base label is 262153, the incoming label from Router 1 is 262153, and the outgoing label to Router 1 is 262162.

    user@Router3> show vpls connections instance edut extensive
    Instance: edut
      Local site: router-3 (2)
        Number of local interfaces: 1
        Number of local interfaces up: 1
        IRB interface present: no
        ge-4/0/2.0         
        lsi.1050368         1         Intf - vpls edut local site 2 remote site 1
        Label-base        Offset     Range     Preference
        262153            1          8         100   
        connection-site           Type  St     Time last up          # Up trans
        1                         rmt   Up     Jun 14 12:26:31 2009           1
          Remote PE: 10.10.10.1, Negotiated control-word: No
          Incoming label: 262153, Outgoing label: 262162
          Local interface: lsi.1050368, Status: Up, Encapsulation: VPLS
            Description: Intf - vpls edut local site 2 remote site 1
        Connection History:
            Jun 14 12:26:31 2009  status update timer  
            Jun 14 12:26:31 2009  loc intf up                  lsi.1050368
            Jun 14 12:26:31 2009  PE route changed     
            Jun 14 12:26:31 2009  Out lbl Update                    262162
            Jun 14 12:26:31 2009  In lbl Update                     262153
            Jun 14 12:26:31 2009  loc intf down
    
    Layer-2 VPN connections:
    
    Legend for connection status (St)   
    EI -- encapsulation invalid      NC -- interface encapsulation not CCC/TCC/VPLS
    EM -- encapsulation mismatch     WE -- interface and instance encaps not same
    VC-Dn -- Virtual circuit down    NP -- interface hardware not present 
    CM -- control-word mismatch      -< -- only outbound connection is up
    CN -- circuit not provisioned    >- -- only inbound connection is up
    OR -- out of range               Up -- operational
    OL -- no outgoing label          Dn -- down                      
    LD -- local site signaled down   CF -- call admission control failure      
    RD -- remote site signaled down  SC -- local and remote site ID collision
    LN -- local site not designated  LM -- local site ID not minimum designated
    RN -- remote site not designated RM -- remote site ID not minimum designated
    XX -- unknown connection status  IL -- no incoming label
    MM -- MTU mismatch               MI -- Mesh-Group ID not availble
    BK -- Backup connection          ST -- Standby connection
    PF -- Profile parse failure      PB -- Profile busy
    
    Legend for interface status 
    Up -- operational           
    Dn -- down
    

Published: 2010-04-27

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