(Optional) Blocking Synchronization Between LDP and IS-IS on an Interface

Context

The ldp-sync enable command run in an IS-IS process enables synchronization between LDP and IS-IS on all local IS-IS interfaces. On an IS-IS interface transmits importance services, LDP and IS-IS synchronization may affect service transmission. If the link is working properly and an LDP session over the link fails, IS-IS sends link state PDUs (LSPs) to advertise the maximum cost of the link. As a result, IS-IS does not select the route for the link, which affects important service transmission.

To prevent the preceding problem, block LDP and IS-IS synchronization on an IS-IS interface that transmits important services.

Procedure

Run system-view
The system view is displayed.
Run interface interface-type interface-number
The IS-IS interface view is displayed.
(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.
Run isis ldp-sync block
Synchronization between LDP and IS-IS is blocked on the interface.

By default, synchronization between LDP and IS-IS is not blocked on an interface.