Example setting up MPLS-LDP

Overview

Multiprotocol Label Switching (MPLS) is a protocol-agnostic routing technique that forwards the data from one node to the next node based on labels rather than network addresses. MPLS allows data packets to be forwarded at layer-2, switching level- of the OSI model rather than passing upto layer-3. For this reason, it is often referred as operating at layer-2.5

 

Topology

 

 

 

 

Instructions

  1. The first step is to configure the interfaces, establish the layer-3 reachability between PE-1 and PE2 via P router using OSPF as IGP protocol

  2. Configure LDP as signalling MPLS protocol on PE1, P1 and PE2 routers. On CE1 and CE2, configure OSPF alone

  3. Post configuration, verify and validate MPLS-LDP neighbourship is up and running b/n PE1 / P1 and P1 / PE2

 

Configure PE1 router

1 2 3 4 5 6 7 8 set interfaces dataplane dp0s4 address 20.1.1.1/24 set interfaces dataplane loopback lo address 1.1.1.1/32 set protocols mpls-ldp address-family ipv4 discovery interface interface dp0s4 set protocols mpls-ldp address-family ipv4 label-policy allocate host-routes set protocols mpls-ldp address-family ipv4 transport-address 1.1.1.1 set protocols mpls-ldp lsr-id 1.1.1.1 set protocols ospf area 0 network 20.1.1.0/24 set protocols ospf area 0 network 1.1.1.1/32

 

Configure P router

1 2 3 4 5 6 7 8 9 10 11 set interfaces dataplane dp0s3 address 20.1.1.2/24 set interfaces dataplane dp0s8 address 30.1.1.2/24 set interfaces dataplane loopback lo address 2.2.2.2/32 set protocols mpls-ldp address-family ipv4 discovery interface interface dp0s3 set protocols mpls-ldp address-family ipv4 discovery interface interface dp0s8 set protocols mpls-ldp address-family ipv4 label-policy allocate host-routes set protocols mpls-ldp address-family ipv4 transport-address 2.2.2.2 set protocols mpls-ldp lsr-id 2.2.2.2 set protocols ospf area 0 network 20.1.1.0/24 set protocols ospf area 0 network 30.1.1.0/24 set protocols ospf area 0 network 2.2.2.2/32

 

Configure PE2 router

1 2 3 4 5 6 7 8 set interfaces dataplane dp0s8 address 30.1.1.1/24 set interfaces dataplane loopback lo address 3.3.3.3/32 set protocols mpls-ldp address-family ipv4 discovery interface interface dp0s8 set protocols mpls-ldp address-family ipv4 label-policy allocate host-routes set protocols mpls-ldp address-family ipv4 transport-address 3.3.3.3 set protocols mpls-ldp lsr-id 3.3.3.3 set protocols ospf area 0 network 30.1.1.0/24 set protocols ospf area 0 network 3.3.3.3/32

 

Validation

show protocols mpls-ldp neighbor

1 2 3 show protocols mpls-ldp neighbor AF ID State Remote Address Uptime ipv4 2.2.2.2 OPERATIONAL 2.2.2.2 00:00:32

 

show protocols mpls-ldp ipv4 interface

1 2 3 4 show protocols mpls-ldp ipv4 interface AF Interface State Uptime Hello Timers ac ipv4 dp0s3 ACTIVE 00:00:42 5/15 2 ipv4 dp0s8 ACTIVE 00:00:42 5/15 2

 

show protocols mpls-ldp ipv4 discovery

1 2 3 4 5 show protocols mpls-ldp ipv4 discovery AF ID Type Source Holdtime[m ipv4 2.2.2.2 Link dp0s4 15 ipv4 2.2.2.2 Link dp0s4 15 ipv4 3.3.3.3 Link dp0s4 15