Saturday, April 14, 2012

MPLS configuration


  • MPLS also called Dynamic Label Switching
  • Before configuring first enable the CEF
    • command used is ip cef in global mode
    • Verify by show command show ip cef
    • It increases the packet switching speed.
    • main
  • Enable MPLS forwarding of ipv4 packets along the routed paths( also called Dynamic Label Switching
    • must be enable on interface & device
    • command: mpls ip

  • unique router-id important in MPLS
    • As a router-id loopback address is more advantage than interface address 
      • command used to router-id as loopback is
      • mpls ldp router-id loopback0 force
  • In sometimes loopback ip address used as router-id cannot be reachable
    • at that time an interface is used as router-id, to this use the following command under interface
      •  mpls ldp discovery transport-address interface
  • enable mpls on routing protocol enabled interfaces
    • mpls ldp autoconfig under routing process.
  • enable mpls authentication globally.
      • mpls ldp password required  in global mode
      • mpls ldp neighbour 150.1.5.55 password CISCO
  • to show mpls neighbours
    • show mpls ldp neighbors
  • to show mpls enabled interfaces
    • show mpls interfaces
  • to show mpls authentication
    • show mpls ldp neighbor password
  • to show LFIB table
    • show mpls forwarding-table
  • to check the packets are forwarding by MPLS
    • traceroute 150.1.5.5
  • normally LDP will generate & adverties labels for every prefix found in the local routing table
    • to avoid this & enable only on some prefixes uses the access control list
    • exampls:
                                access-list 10 permit 150.1.0.0 0.0.255.255
                                 no mpls ldp advertise-labels
                                 mpls ldp advertise-labels for 10
  • PE configuration
    • in mpls network full mesh of PEs was created using ibgp peerings
    • for example
router bgp 100
    neighbor 155.1.5.5 remote-as 1oopback0
    neighbor 155.1.5.5 update-source loopback0
    address-family vpv4 unicast         /** activating vpv4 address family
    neighbor 150.1.5.5 activate 
    neighbor 150.1.5.5 send-community extended
   neighbor 150.1.5.5 route-reflector-client

  •   to define VRF use command
    • ip vrf vrf-name