MPLS ldp advertised-labels

Hey did you manage to get the MPLS label advertisement filters working in IOU?


eg


mpls ldp advertise-labels for MY_PREFIXES to YOUR_LOOPBACK


I can't seem to stop it generating labels for everything in the RIB even though I'm sure the config is correct.


Did you have a similar problem?

The interface addressing is confusing in the new INE full-scale lab, but after some testing, I found that the command for ADVERTISED-LABELS does work correctly in IOU. 

Are you sure that your config is correct?  Or is it your verification method?

 

The local routers with the restricted advertised-labels (R3,R4) will still generate LOCAL labels for their own mpls forwarding tables.  But what we are concerned about, are the labels that are actually ADVERTISED.

If in doubt, a simple trick is to look at the connecting routers.  What do the LDP neighbors see for labels?

R3# sh mpls ldp neighbor | in Peer
    Peer LDP Ident: 192.122.3.6:0; Local LDP Ident 192.122.3.3:0
    Peer LDP Ident: 192.122.3.5:0; Local LDP Ident 192.122.3.3:0
    Peer LDP Ident: 192.122.3.4:0; Local LDP Ident 192.122.3.3:0
    Peer LDP Ident: 192.122.3.1:0; Local LDP Ident 192.122.3.3:0

R4# sh mpls ldp neighbor | in Peer
    Peer LDP Ident: 192.122.3.5:0; Local LDP Ident 192.122.3.4:0
    Peer LDP Ident: 192.122.3.6:0; Local LDP Ident 192.122.3.4:0
    Peer LDP Ident: 192.122.3.3:0; Local LDP Ident 192.122.3.4:0
    Peer LDP Ident: 192.122.3.2:0; Local LDP Ident 192.122.3.4:0

 

Config (R3/R4):

no mpls ldp advertise-labels
mpls ldp advertise-labels for 34

access-list 34 permit 192.122.3.2
access-list 34 permit 192.122.3.7
access-list 34 permit 192.122.3.6
access-list 34 permit 192.122.3.8

 

So now we can go to any of these neighbors (peers) and look at what labels they receive from R3 and R4. Notice that I changed the label ranges so that it is easier to track what labels we are seeing.

R6# sh mpls forwarding-table | in 0.36|0.46 <--interfaces to R3 and R4
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
600005     No Label   10.0.13.0/30     0             Et0/0.36   10.0.36.1
600006     No Label   10.0.23.0/30     0             Et0/0.36   10.0.36.1
600007     No Label   10.0.34.0/30     0             Et0/0.36   10.0.36.1
           No Label   10.0.34.0/30     0             Et0/0.46   10.0.46.1
           No Label   10.0.35.0/30     0             Et0/0.36   10.0.36.1
600009     No Label   10.0.14.0/30     0             Et0/0.46   10.0.46.1
600010     No Label   10.0.24.0/30     0             Et0/0.46   10.0.46.1
           No Label   10.0.45.0/30     0             Et0/0.46   10.0.46.1


R5# sh mpls forwarding-table | in 0.35|0.45 <--interfaces to R3 and R4
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
500001     No Label   10.0.13.0/30     0             Et0/0.35   10.0.35.1
500002     No Label   10.0.23.0/30     0             Et0/0.35   10.0.35.1
500003     No Label   10.0.34.0/30     0             Et0/0.35   10.0.35.1
           No Label   10.0.34.0/30     0             Et0/0.45   10.0.45.1
           No Label   10.0.36.0/30     0             Et0/0.35   10.0.35.1
500020     No Label   10.0.24.0/30     0             Et0/0.45   10.0.45.1
500021     No Label   10.0.14.0/30     0             Et0/0.45   10.0.45.1
           No Label   10.0.46.0/30     0             Et0/0.45   10.0.45.1

 

R4# sh mpls forwarding-table | in 0.34 <-- interface to R3
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
400008     No Label   10.0.13.2/32     0             Et0/0.34   10.0.34.1
400010     No Label   10.0.35.0/30     0             Et0/0.34   10.0.34.1
400011     No Label   10.0.36.0/30     0             Et0/0.34   10.0.34.1
400012     No Label   10.0.56.0/30     0             Et0/0.34   10.0.34.1
           No Label   89.211.116.0/25  0             Et0/0.34   10.0.34.1
400014     No Label   89.211.117.0/25  0             Et0/0.34   10.0.34.1
400015     No Label   136.5.17.0/24    0             Et0/0.34   10.0.34.1
400016     No Label   136.5.18.0/24    0             Et0/0.34   10.0.34.1
400017     No Label   136.6.58.0/24    0             Et0/0.34   10.0.34.1
400018     No Label   172.30.78.0/27   0             Et0/0.34   10.0.34.1
400019     No Label   192.122.3.1/32   0             Et0/0.34   10.0.34.1
400020     No Label   192.122.3.3/32   0             Et0/0.34   10.0.34.1
400021     No Label   192.122.3.5/32   0             Et0/0.34   10.0.34.1
400022     300021     192.122.3.6/32   0             Et0/0.34   10.0.34.1
400023     300022     192.122.3.7/32   0             Et0/0.34   10.0.34.1
400024     300023     192.122.3.8/32   0             Et0/0.34   10.0.34.1
400027     No Label   10.0.13.1/32     0             Et0/0.34   10.0.34.1

 

R3#sh mpls forwarding-table  | in 0.34 <-- interface to R4
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
300009     No Label   10.0.24.0/30     0             Et0/0.34   10.0.34.2
           No Label   192.122.3.16/32  0             Et0/0.34   10.0.34.2
           No Label   202.4.216.0/26   0             Et0/0.34   10.0.34.2
300026     400028     192.122.3.2/32   7200          Et0/0.34   10.0.34.2
300028     No Label   192.122.3.4/32   0             Et0/0.34   10.0.34.2

 

R2#sh mpls forwarding-table | in /0.24 <-- interface to R4
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
200002     No Label   192.122.3.1/32   0             Et0/0.24   10.0.24.2
200003     No Label   10.0.13.1/32     0             Et0/0.24   10.0.24.2
200004     No Label   89.211.117.0/25  0             Et0/0.24   10.0.24.2
200019     No Label   10.0.34.0/30     0             Et0/0.24   10.0.24.2
200021     No Label   10.0.13.2/32     0             Et0/0.24   10.0.24.2
200022     No Label   192.122.3.4/32   0             Et0/0.24   10.0.24.2
200023     No Label   192.122.3.3/32   0             Et0/0.24   10.0.24.2

 

R1# sh mpls forwarding-table | in /0.13 <-- interface to R3
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
100020     No Label   10.0.34.0/30     0             Et0/0.13   10.0.13.2
100022     No Label   10.0.24.0/30     0             Et0/0.13   10.0.13.2
100023     Pop Label  10.0.13.2/32     0             Et0/0.13   10.0.13.2
100025     No Label   192.122.3.4/32   48122         Et0/0.13   10.0.13.2
100026     No Label   192.122.3.3/32   48552         Et0/0.13   10.0.13.2
100027     300026     192.122.3.2/32   0             Et0/0.13   10.0.13.2

 

NOTE:  the routing is not optimal (see redistribution solution).  But that is not important for the advertised-labels.

R4trace 192.122.3.6
<snip>
  1 10.0.34.1 [MPLS: Label 300021 Exp 0] 11 msec 54 msec 17 msec
  2 10.0.13.1 [MPLS: Label 100019 Exp 0] 12 msec 25 msec 30 msec
  3 136.5.18.8 [MPLS: Label 800028 Exp 0] 23 msec 13 msec 20 msec
  4 136.6.58.5 [MPLS: Label 500023 Exp 0] 34 msec 20 msec 9 msec
  5 10.0.56.2 11 msec *  53 msec

 

 

 

 

 

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