Post

Juniper Martini PW LDP Requested VLAN ID

Posted
By Fabrizzio Petrucci 5 min read

So this is a short post. I’m studying for the JNCIP-SP and I found very interesting that although l2circuits / Martini PWs need the VLANs at both ends to match, this disappears from the LDP label mapping if there’s outer-vlan-map swap present

PE configs

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fabrizzio@PE01# show interfaces ge-0/0/4.150     
encapsulation vlan-ccc;
vlan-id 150;

fabrizzio@PE01# show protocols l2circuit neighbor 10.254.0.12 interface ge-0/0/4.150 
virtual-circuit-id 2;

fabrizzio@PE03# show interfaces ge-0/0/3.200 
encapsulation vlan-ccc;
vlan-id 200;
input-vlan-map {
    swap;
    vlan-id 150;
}
output-vlan-map swap;

fabrizzio@PE03# show protocols l2circuit neighbor 10.254.0.10 interface ge-0/0/3.200 
virtual-circuit-id 2;

This does work just fine because PE03 is doing the job of the VLAN swapping in both directions.

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fabrizzio@PE01> show l2circuit connections interface ge-0/0/4.150 | find Nei 
Neighbor: 10.254.0.12 
    Interface                 Type  St     Time last up          # Up trans
    ge-0/0/4.150(vc 2)        rmt   Up     Jun 15 09:01:54 2024           1
      Remote PE: 10.254.0.12, Negotiated control-word: Yes (Null)
      Incoming label: 299968, Outgoing label: 299968
      Negotiated PW status TLV: No
      Local interface: ge-0/0/4.150, Status: Up, Encapsulation: VLAN
      Flow Label Transmit: No, Flow Label Receive: No

fabrizzio@PE03> show l2circuit connections interface ge-0/0/3.200 | find Nei   
Neighbor: 10.254.0.10 
    Interface                 Type  St     Time last up          # Up trans
    ge-0/0/3.200(vc 2)        rmt   Up     Jun 15 08:19:26 2024           1
      Remote PE: 10.254.0.10, Negotiated control-word: Yes (Null)
      Incoming label: 299968, Outgoing label: 299968
      Negotiated PW status TLV: No
      Local interface: ge-0/0/3.200, Status: Up, Encapsulation: VLAN
      Flow Label Transmit: No, Flow Label Receive: No

LDP database

I have two Martini PWs built between these PEs.

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fabrizzio@PE01> show ldp database session 10.254.0.12 extensive l2circuit    
Input label database, 10.254.0.10:0--10.254.0.12:0
Labels received: 14
  Label     Prefix
 299952      L2CKT CtrlWord VLAN VC 1
            MTU: 1982 Requested VLAN ID: 100 Flow Label T Bit: 1 Flow Label R Bit: 1
            State: Active
            Age: 59:44
            VCCV Control Channel types:
                PWE3 control word 
                MPLS router alert label 
                MPLS PW label with TTL=1 
            VCCV Control Verification types:
                LSP ping 
                BFD with PW-ACH-encapsulation for Fault Detection 
                BFD with IP/UDP-encapsulation for Fault Detection 
  Label     Prefix
 299968      L2CKT CtrlWord VLAN VC 2
            MTU: 1982 Flow Label T Bit: 0 Flow Label R Bit: 0
            State: Active
            Age: 50:13
            VCCV Control Channel types:
                PWE3 control word 
                MPLS router alert label 
                MPLS PW label with TTL=1 
            VCCV Control Verification types:
                LSP ping 
                BFD with PW-ACH-encapsulation for Fault Detection 
                BFD with IP/UDP-encapsulation for Fault Detection 

Output label database, 10.254.0.10:0--10.254.0.12:0
Labels advertised: 14
  Label     Prefix
 299952      L2CKT CtrlWord VLAN VC 1
            MTU: 1982 Requested VLAN ID: 100
            PW status code: 0x0
            Flow Label T Bit: 1 Flow Label R Bit: 1
            State: Active
            Age: 1:04:01
            VCCV Control Channel types:
                PWE3 control word 
                MPLS router alert label 
                MPLS PW label with TTL=1 
            VCCV Control Verification types:
                LSP ping 
                BFD with PW-ACH-encapsulation for Fault Detection 
                BFD with IP/UDP-encapsulation for Fault Detection 
  Label     Prefix
 299968      L2CKT CtrlWord VLAN VC 2
            MTU: 1982 Requested VLAN ID: 150 Flow Label T Bit: 0 Flow Label R Bit: 0 <<<<<<<<<<<<<<<
            State: Active
            Age: 50:51
            VCCV Control Channel types: 
                PWE3 control word 
                MPLS router alert label 
                MPLS PW label with TTL=1 
            VCCV Control Verification types:
                LSP ping 
                BFD with PW-ACH-encapsulation for Fault Detection 
                BFD with IP/UDP-encapsulation for Fault Detection

The interesting part is that as seen right now, the label mapping PE01 receives from PE03 (label 299968) doesn’t contain any requested VLAN ID. The mapping sent from PE01 to PE03 (same label 299968) does request the VLAN 150.

Adding output-vlan-map swap

Added on PE01 side

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fabrizzio@PE01# show interfaces ge-0/0/4.150 
encapsulation vlan-ccc;
vlan-id 150;
output-vlan-map swap;

Now PE01 doesn’t request any VLAN :)

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fabrizzio@PE01> show ldp database session 10.254.0.12 extensive l2circuit    
Input label database, 10.254.0.10:0--10.254.0.12:0
Labels received: 14
  Label     Prefix
 299952      L2CKT CtrlWord VLAN VC 1
            MTU: 1982 Requested VLAN ID: 100 Flow Label T Bit: 1 Flow Label R Bit: 1
            State: Active
            Age: 1:03:03
            VCCV Control Channel types:
                PWE3 control word 
                MPLS router alert label 
                MPLS PW label with TTL=1 
            VCCV Control Verification types:
                LSP ping 
                BFD with PW-ACH-encapsulation for Fault Detection 
                BFD with IP/UDP-encapsulation for Fault Detection 
  Label     Prefix
 299968      L2CKT CtrlWord VLAN VC 2
            MTU: 1982 Flow Label T Bit: 0 Flow Label R Bit: 0
            State: Active
            Age: 53:32
            VCCV Control Channel types:
                PWE3 control word 
                MPLS router alert label 
                MPLS PW label with TTL=1 
            VCCV Control Verification types:
                LSP ping 
                BFD with PW-ACH-encapsulation for Fault Detection 
                BFD with IP/UDP-encapsulation for Fault Detection 

Output label database, 10.254.0.10:0--10.254.0.12:0
Labels advertised: 14
  Label     Prefix
 299952      L2CKT CtrlWord VLAN VC 1
            MTU: 1982 Requested VLAN ID: 100
            PW status code: 0x0
            Flow Label T Bit: 1 Flow Label R Bit: 1
            State: Active
            Age: 1:07:20
            VCCV Control Channel types:
                PWE3 control word 
                MPLS router alert label 
                MPLS PW label with TTL=1 
            VCCV Control Verification types:
                LSP ping 
                BFD with PW-ACH-encapsulation for Fault Detection 
                BFD with IP/UDP-encapsulation for Fault Detection 
  Label     Prefix
 299968      L2CKT CtrlWord VLAN VC 2
            MTU: 1982 Flow Label T Bit: 0 Flow Label R Bit: 0 <<<<<<<<<<<<<<<
            State: Active
            Age: 54:10
            VCCV Control Channel types: 
                PWE3 control word 
                MPLS router alert label 
                MPLS PW label with TTL=1 
            VCCV Control Verification types:
                LSP ping 
                BFD with PW-ACH-encapsulation for Fault Detection 
                BFD with IP/UDP-encapsulation for Fault Detection

I just found this interesting.

Juniper, JNCIP-SP, Martini, l2circuit
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This post is licensed under CC BY 4.0 by the author.

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