Example for Configuring Local LDP Sessions

This section provides an example for configuring local LDP sessions. The configuration procedure involves enabling MPLS and MPLS LDP on each LSR and interface.

Networking Requirements

In Figure 1, LSRA, LSRB, and LSRC function as core or edge devices on a backbone network. To deploy MPLS LDP services on the backbone network, configure local LDP sessions between LSRA and LSRB, and between LSRB and LSRC. Each pair of LSRs distributes labels to each other and establishes LDP LSPs.

Figure 1 Local LDP sessions

Interfaces 1 and 2 represent GE 0/1/0 and GE 0/1/8, respectively.

Configuration Notes

When configuring local LDP sessions, note the following:

An LSR ID must be configured before you run other MPLS commands.
An LSR ID of an LSR must be manually configured because no default LSR ID is available.
Using the IP address of a reachable loopback interface on an LSR as an LSR ID is recommended.

Configuration Roadmap

The configuration roadmap is as follows:

Assign an IP address to each interface and configure OSPF to advertise the route to the network segment to which each interface is connected and the host route to each LSR ID.
Enable MPLS and MPLS LDP globally on each LSR.
Enable MPLS on interfaces of each LSR.
Enable MPLS LDP on the interfaces of both ends of each local LDP session.

Data Preparation

To complete the configuration, you need the following data:

IP address of each interface on each LSR as shown in Figure 1, OSPF process ID, and OSPF area ID
LSR ID of each LSR

Procedure

Assign an IP address to each interface and configure OSPF to advertise the route to the network segment to which each interface is connected and the host route to each LSR ID.
According to Figure 1, assign an IP address to each interface, configure the loopback interface addresses as LSR IDs, and configure OSPF to advertise the route to the network segment to which each interface is connected and the host route to each LSR ID. For configuration details, see Configuration Files in this section.

Enable MPLS and MPLS LDP globally on each LSR.

# Configure LSRA.

<LSRA> system-view 
[*LSRA] mpls lsr-id 1.1.1.9
[*LSRA] mpls
[*LSRA-mpls] quit
[*LSRA] mpls ldp
[*LSRA-mpls-ldp] commit
[~LSRA-mpls-ldp] quit

# Configure LSRB.

<LSRB> system-view 
[*LSRB] mpls lsr-id 2.2.2.9
[*LSRB] mpls
[*LSRB-mpls] quit
[*LSRB] mpls ldp
[*LSRB-mpls-ldp] commit
[~LSRB-mpls-ldp] quit

# Configure LSRC.

<LSRC> system-view 
[*LSRC] mpls lsr-id 3.3.3.9
[*LSRC] mpls
[*LSRC-mpls] quit
[*LSRC] mpls ldp
[*LSRC-mpls-ldp] commit
[~LSRC-mpls-ldp] quit

Enable MPLS and MPLS LDP on the interfaces of each LSR.

# Configure LSRA.

[~LSRA] interface gigabitethernet 0/1/0
[~LSRA-GigabitEthernet0/1/0] mpls
[*LSRA-GigabitEthernet0/1/0] mpls ldp
[*LSRA-GigabitEthernet0/1/0] commit
[~LSRA-GigabitEthernet0/1/0] quit

# Configure LSRB.

[~LSRB] interface gigabitethernet 0/1/0
[~LSRB-GigabitEthernet0/1/0] mpls
[*LSRB-GigabitEthernet0/1/0] mpls ldp
[*LSRB-GigabitEthernet0/1/0] commit
[~LSRB-GigabitEthernet0/1/0] quit
[~LSRB] interface gigabitethernet 0/1/8
[~LSRB-GigabitEthernet0/1/8] mpls
[*LSRB-GigabitEthernet0/1/8] mpls ldp
[*LSRB-GigabitEthernet0/1/8] commit
[~LSRB-GigabitEthernet0/1/8] quit

# Configure LSRC.

[~LSRC] interface gigabitethernet 0/1/0
[*LSRC-GigabitEthernet0/1/0] mpls
[*LSRC-GigabitEthernet0/1/0] mpls ldp
[*LSRC-GigabitEthernet0/1/0] commit
[~LSRC-GigabitEthernet0/1/0] quit

Verify the configuration.

# After completing the configuration, run the display mpls ldp session command on an LSR. The command output shows that the status of the local LDP session between LSRA and LSRB, or between LSRB and LSRC is Operational.

The following example uses the command output on LSRA.

<LSRA> display mpls ldp session
 LDP Session(s) in Public Network
 Codes: LAM(Label Advertisement Mode), SsnAge Unit(DDDD:HH:MM)
 An asterisk (*) before a session means the session is being deleted.
--------------------------------------------------------------------------
 PeerID             Status      LAM  SsnRole  SsnAge       KASent/Rcv
--------------------------------------------------------------------------
2.2.2.9:0           Operational DU   Passive  0000:00:22   91/91
--------------------------------------------------------------------------
TOTAL: 1 Session(s) Found.

Configuration Files

LSRA configuration file

#
sysname LSRA
#
mpls lsr-id 1.1.1.9
#
mpls
#
mpls ldp
#
 ipv4-family
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.1.1.1 255.255.255.252
 mpls
 mpls ldp
#
interface LoopBack1
 ip address 1.1.1.9 255.255.255.255
#
ospf 1
 area 0.0.0.0
  network 1.1.1.9 0.0.0.0
  network 10.1.1.0 0.0.0.3
#
return

LSRB configuration file

#
sysname LSRB
#
mpls lsr-id 2.2.2.9
#
mpls
#
mpls ldp
#
 ipv4-family
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.1.1.2 255.255.255.252
 mpls
 mpls ldp
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.2.1.1 255.255.255.252
 mpls
 mpls ldp
#
interface LoopBack1
 ip address 2.2.2.9 255.255.255.255
#
ospf 1
 area 0.0.0.0
  network 2.2.2.9 0.0.0.0
  network 10.1.1.0 0.0.0.3
  network 10.2.1.0 0.0.0.3
#
return

LSRC configuration file

#
sysname LSRC
#
mpls lsr-id 3.3.3.9
#
mpls
#
mpls ldp
 #
 ipv4-family
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.2.1.2 255.255.255.252
 mpls
 mpls ldp
#
interface LoopBack1
 ip address 3.3.3.9 255.255.255.255
#
ospf 1
 area 0.0.0.0
  network 3.3.3.9 0.0.0.0
  network 10.2.1.0 0.0.0.3
#
return