MPLS CHAPTER 1

MPLS CHAP 1

QUESTIONS CHAP 1
1. What are the commands to enable MPLS and where  are the commands used ?
2. How do you verify the local label a router has chosen for a given network ?
3. How do you verify which label a router will impose

SOLUTIONS :
1. What are the commands to enable MPLS and where  are the commands used ?
if we enable mpls ip at global config mode it will enable mpls on all the interfaces.
so enable mpls ip on per interface basis.

in this diagram enable mpls ip  on the interface within the square box , R1 fa0/0
R2 f0/0-f0/1 & R3 f0/1.
2. How do you verify the local label a router has chosen for a given network ?
For LIB table:
R2#sh mpls ldp bindings 1.1.1.1 32
  tib entry: 1.1.1.1/32, rev 2
        local binding:  tag: 16
        remote binding: tsr: 1.1.1.1:0, tag: imp-null
        remote binding: tsr: 3.3.3.3:0, tag: 16
R2#sh mpls ldp bindings 3.3.3.3 32
  tib entry: 3.3.3.3/32, rev 6
        local binding:  tag: 17
        remote binding: tsr: 1.1.1.1:0, tag: 501
        remote binding: tsr: 3.3.3.3:0, tag: imp-null
for LFIB table:
R2#sh mpls forwarding-table 1.1.1.1
Local  Outgoing    Prefix            Bytes tag  Outgoing   Next Hop
tag    tag or VC   or Tunnel Id      switched   interface
16     Pop tag     1.1.1.1/32        0          Fa0/0      10.1.12.1
R2#sh mpls forw
R2#sh mpls forwarding-table 3.3.3.3
Local  Outgoing    Prefix            Bytes tag  Outgoing   Next Hop
tag    tag or VC   or Tunnel Id      switched   interface
17     Pop tag     3.3.3.3/32        0          Fa0/1      10.1.23.3
3. How do you verify which label a router will impose
R1#sh ip cef 3.3.3.3
3.3.3.3/32, version 13, epoch 0, cached adjacency 10.1.12.2
0 packets, 0 bytes
  tag information set
    local tag: 501
    fast tag rewrite with Fa0/0, 10.1.12.2, tags imposed: {17}
  via 10.1.12.2, FastEthernet0/0, 0 dependencies
    next hop 10.1.12.2, FastEthernet0/0
    valid cached adjacency
    tag rewrite with Fa0/0, 10.1.12.2, tags imposed: {17}