Network Requirement

Figure 1. MPLS LDP Configuration Example

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LSR 1 and LSR 3 serve as the PE (Provider Edge) devices in the IP/MPLS backbone network. MPLS LDP (Label Distribution Protocol) needs to be configured on both LSR 1 and LSR 3 to establish LDP LSPs (Label Switched Paths), enabling the interconnection of LSP networks and supporting business traffic transmission.

Configure MPLS LDP as follows:

1. Configure OSPF on each LSR to ensure IP connectivity in the backbone network. This includes configuring OSPF protocol and relevant network segments, areas, and neighbor relationships.

2. Configure MPLS LDP on each LSR. This involves enabling MPLS functionality and configuring LDP protocol parameters such as LDP session parameters, LDP neighbor relationships, and LDP label distribution policies.

With this configuration, each LSR will be able to establish an IP/MPLS network and create LDP LSPs through MPLS LDP, thereby achieving interconnection and business transmission of LSP networks.

Procedure

LSR 1

Step 1         Configure VLAN interface.

Step 2         Configure the OSPF protocol to advertise the network segments connected to each node's interfaces and the LSR's host routes.

Step 3         Enable MPLS on the L3 interface.

Step 4         Enable MPLS LDP on the L3 interface.

Step 5         Configure MPLS router ID.

Step 6         Configure MPLS LDP transmission address under IPv4 address family.

Step 7         Configure LDP ordered label distribution control.

Step 8         Enable IP routing.

Step 9         Commit the configuration.  

LSR 2

Step 1         Configure VLAN interface.

Step 2         Configure the OSPF protocol to advertise the network segments connected to each node's interfaces and the LSR's host routes.

Step 3         Enable MPLS on the L3 interface.

Step 4         Enable MPLS LDP on the L3 interface. Usually, both the incoming and outgoing interfaces of the packets need to enable MPLS. By default, MPLS is disabled on the L3 interface.

Step 5         Configure MPLS router ID.

Step 6         Configure MPLS LDP transmission address under IPv4 address family.

Step 7         Configure LDP ordered label distribution control.

Step 8         Enable IP routing.

Step 9         Commit the configuration.  

LSR 3

Step 1         Configure VLAN interface.

Step 2         Configure the OSPF protocol to advertise the network segments connected to each node's interfaces and the LSR's host routes.

Step 3         Enable MPLS on the L3 interface.

Step 4         Enable MPLS on the L3 interface. Usually, both the incoming and outgoing interfaces of the packets need to enable MPLS. By default, MPLS is disabled on the L3 interface.

Step 5         Configure MPLS router ID.

Step 6         Configure MPLS LDP transmission address under IPv4 address family.

Step 7         Configure LDP ordered label distribution control.

Step 8         Enable IP routing.

Step 9          Commit the configuration.  

Verify the Configuration

• After the configuration is complete, run command run show mpls ldp neighbor on each LSR. From the show result, we can see that MPLS LDP state is “OPERATIONAL“, indicating successful establishment of LDP session. Take LSR 2 as an example:

• After the configuration is complete, run command run show mpls ldp binding to verify label bindings.

In the show result, the parameter “In Use” indicates whether the label binding entry is effective or not.

• yes: indicates the label binding entry is effective.

• no: indicates the label binding entry is ineffective.