Configuring One-Arm BFD for E2E SR-MPLS TE Tunnel

One-arm BFD for E2E SR-MPLS TE tunnel quickly detects faults on inter-AS E2E SR-MPLS TE tunnels and protects traffic on the E2E SR-MPLS TE tunnels.

Usage Scenario

If one-arm BFD for inter-AS E2E SR-MPLS TE tunnel detects a fault on the primary tunnel, a protection application, for example, VPN FRR, rapidly switches traffic, which minimizes the impact on traffic.

With one-arm BFD for E2E SR-MPLS TE tunnel enabled, if the reflector can successfully iterate packets to the E2E SR-MPLS TE tunnel using the IP address of the initiator, the reflector forwards the packets through the E2E SR-MPLS TE tunnel. Otherwise, the reflector forwards the packets over IP routes.

Pre-configuration Tasks

Before configuring one-arm BFD for E2E SR-MPLS TE tunnel, configure an inter-AS E2E SR-MPLS TE tunnel.

Procedure

Enable BFD globally.
1. Run system-view
  The system view is displayed.
2. Run bfd
  BFD is enabled.
3. Run commit
  The configuration is committed.
Enable the ingress to dynamically create a BFD session to monitor E2E SR-MPLS TE tunnels.
Perform either of the following operations:
- Globally enable the capability if BFD sessions need to be automatically created for most E2E SR-MPLS TE tunnels on the ingress.
- Enable the capability on a specific tunnel interface if a BFD session needs to be automatically created for some E2E SR-MPLS TE tunnels on the ingress.
Run the following commands as needed.
- Enable the capability globally.
  1. Run system-view
    The system view is displayed.
  2. Run mpls
    The MPLS view is displayed.
  3. Run mpls te bfd tunnel enable one-arm-echo
    
    One-arm BFD for E2E SR-MPLS TE tunnel is enabled.
  4. Run quit
    Return to the system view.
  5. Run interface tunnel interface-number
    The view of the E2E SR-MPLS TE tunnel interface is displayed.
  6. Run mpls te reverse-lsp binding-sid label label-value
    
    A binding SID is set for a reverse LSP in the E2E SR-MPLS TE tunnel.
    
    Ensure that the mpls te binding-sid label label-value command has been run on the ingress of the reverse LSP.
  7. (Optional) Run mpls te bfd block
    
    The capability of automatically creating BFD sessions for the E2E SR-MPLS TE tunnel is blocked.
    
    If some SR-MPLS TE tunnels do not need to be monitored using BFD for E2E SR-MPLS TE tunnel, block this capability on each tunnel interface:
  8. Run commit
    The configuration is committed.
- Enable the capability on a tunnel interface.
  - Run system-view
    
    The system view is displayed.
  - Run interface tunnel interface-number
    
    The view of the E2E SR-MPLS TE tunnel interface is displayed.
  - Run mpls te bfd tunnel enable one-arm-echo
    
    One-arm BFD for E2E SR-MPLS TE tunnel is enabled.
    
    This command run in the tunnel interface view takes effect only on the tunnel interface.
  - Run mpls te reverse-lsp binding-sid label label-value
    
    A binding SID is set for a reverse LSP in the E2E SR-MPLS TE tunnel.
    
    Ensure that the mpls te binding-sid label label-value command has been run on the ingress of the reverse LSP.
  - Run commit
    
    The configuration is committed.
(Optional) Adjust BFD parameters on the ingress.
Adjust BFD parameters on the ingress in either of the following modes:
- Adjust BFD parameters globally. This method is used when BFD parameters for most E2E SR-MPLS TE tunnels need to be adjusted on the ingress.
- Adjust BFD parameters on a specific tunnel interface. If an E2E SR-MPLS TE tunnel interface needs BFD parameters different from the globally configured ones, adjust BFD parameters on the specific tunnel interface.
In one-arm BFD for E2E SR-MPLS TE mode, BFD does not need to be enabled on the peer, and the min-tx-interval tx-interval parameter of the local end does not take effect. Therefore, the actual detection period of the ingress equals the configured interval at which BFD packets are received on the ingress multiplied by the detection multiplier configured on the ingress.

Run the following commands as needed.
- Adjust BFD parameters globally.
  - Run system-view
    
    The system view is displayed.
  - Run mpls
    
    The MPLS view is displayed.
  - Run mpls te bfd tunnel { min-rx-interval rx-interval | detect-multiplier multiplier } ^*
    
    BFD parameters are set.
  - Run commit
    
    The configuration is committed.
- Adjust BFD parameters on a specific tunnel interface.
  - Run system-view
    
    The system view is displayed.
  - Run interface tunnel interface-number
    
    The tunnel interface view is displayed.
  - Run mpls te bfd tunnel { min-rx-interval rx-interval | detect-multiplier multiplier } ^*
    
    BFD parameters are set.
  - Run commit
    
    The configuration is committed.

Verifying the Configuration

After successfully configuring one-arm BFD for E2E SR-MPLS TE tunnel, verify the configurations.

Run the display bfd session dynamic [ verbose ] command to check information about BFD sessions on the ingress.
Run the following commands to check BFD statistics:
- Run the display bfd statistics command to check all BFD statistics.
- Run the display bfd statistics session dynamic command to check statistics about dynamic BFD sessions.