(Optional) Configuring an LDP Label Advertisement Mode

Context

By default, a downstream node sends Label Mapping messages to its upstream node. When faults occur on the network, services can be fast switched to the standby path, improving network reliability. Edge devices on the MPLS network are low-end devices. To ensure network reliability, resources must be fully used. You can configure the Downstream on Demand (DoD) mode to save system resources. In DoD mode, the downstream LSR sends a Label Mapping message to the upstream LSR only when the upstream LSR sends a Label Request message to the downstream LSR.

Modifying a configured label advertisement mode leads to the reestablishment of an LDP session, resulting in MPLS service interruption.

When the local and remote LDP sessions coexist, they must be configured with the same label advertisement mode.

Procedure

Configuring an LDP label advertisement mode of local LDP session.
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. (Optional) On an Ethernet interface, run undo portswitch
  The interface is switched to Layer 3 mode.
  
  By default, an Ethernet interface works in Layer 2 mode.
  
  Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
4. Run mpls ldp advertisement { dod | du }
  A label advertisement mode is configured.
  
  By default, the label advertisement mode is downstream unsolicited (DU).
  
  Inconsistency in label advertisement modes leads to failure in establishing LDP LSPs between the two LDP peers over multiple links.
Configuring an LDP label advertisement mode of remote LDP session.
1. Run system-view
  The system view is displayed.
2. Run mpls ldp remote-peer remote-peer-name
  A remote MPLS LDP peer is created and the remote MPLS LDP peer view is displayed.
3. Run mpls ldp advertisement { dod | du }
  A label advertisement mode is configured.
  
  By default, the label advertisement mode is downstream unsolicited (DU).