Basic LDP

Lab file

19KB

Challenge - Basic LDP.yaml

Startup configs

7KB

basic_ldp_initial_configs.zip

archive

In this lab you will configure basic LDP features. IP addresses are already pre-configured.

Objective

For this lab, do not make any changes to XR2 or R2.

1. On R1:

   • Confgure OSPF using process 1 and area 0

     • Gi1 should be p2p

     • Advertise all loopbacks into OSPF

     • Use md5 authentication with password cisco123 and key 1

   • Configure LDP

     • Establish an LDP neighborship with XR2

     • Use LDP authentication with password cisco456

     • Make XR2’s LFIB look like this:

   RP/0/0/CPU0:XR2#show mpls forwarding 
   Mon Oct 17 13:03:37.977 UTC
   Local  Outgoing    Prefix             Outgoing     Next Hop        Bytes       
   Label  Label       or ID              Interface                    Switched    
   ------ ----------- ------------------ ------------ --------------- ------------
   24000  Pop         1.1.1.1/32         Gi0/0/0/0    10.1.2.1        60          
   24001  Pop         1.1.1.10/32        Gi0/0/0/0    10.1.2.1        0           
   24002  Unlabelled  1.1.1.20/32        Gi0/0/0/0    10.1.2.1        0

2. Preform the same exercise on XR1. R2’s LFIB should look like this:

   R2#show mpls forwarding-table 
   Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    
   Label      Label      or Tunnel Id     Switched      interface              
   16         No Label   1.1.1.20/32      0             Gi1        10.1.2.1    
   17         Pop Label  1.1.1.10/32      0             Gi1        10.1.2.1    
   18         Pop Label  1.1.1.1/32       0             Gi1        10.1.2.1

Answers

Using OSPF and LDP authentication is fairly well documented, so if you have trouble with this I would recommend looking up documentation on these features. You will learn more by finding the answers yourself than if I simply list the configuration here.

In order to make XR2’s LFIB entry for 1.1.1.20/32 unlabeled, you must filter advertisement of this label binding from R1, using LDP conditional label advertisement. Ensure that you are disabling the default advertisement of all label allocations.

Likewise on XR1 you must configure LDP conditional label advertisement. Ensure on XR1 that you are disabling the default advertisement of all label allocations using label local advertise disable as well.