During fault rectification in a link protection scenario, if service VSI PWs go Up before protocol VSI PWs, service VSI loops occur. To prevent this issue, you can configure an L2VPN monitoring group to monitor the VSI recovery status and delay the unlocking of service VSI PWs.
Usage Scenario
In a link protection scenario, if a device restarts, a board resets, or both the primary and secondary PWs become faulty, service VSI PWs and protocol VSI PWs also fail. When the fault is rectified, service VSI PWs may go Up before protocol VSI PWs. This results in service VSI loops and adversely affects service traffic.
To prevent this issue, you can create an L2VPN monitoring group, bind the protocol VSI PWs to the monitoring group, and specify the monitoring group to be tracked in the service VSI. If the service VSI PWs go Up before the protocol VSI PWs bound to the L2VPN monitoring group, the device blocks the service VSI PWs by changing their status to not forwarding. When all the protocol VSI PWs bound to the monitoring group go Up, the hold-off timer is started. After the timer expires, the service VSI PWs are unblocked. This ensures that service VSI loops do not occur in such a scenario.
A service VSI transmits service data, whereas a protocol VSI transmits the link protection protocol packets.
Pre-configuration Tasks
Before configuring an L2VPN monitoring group, complete the following tasks:
- Create protocol VSIs and PWs.
- Create service VSIs and PWs.
- Configure link protection.
Procedure
- Configure an L2VPN monitoring group and set a hold-off time for unblocking service VSI PWs.
- Run system-view
The system view is displayed.
- Run mpls
MPLS is enabled.
- Run quit
Return to the system view.
- Run mpls l2vpn
The MPLS L2VPN view is displayed.
- Run monitor-group monitor-group-name
An L2VPN monitoring group is configured.
- Run monitor enable
The monitoring capability of the L2VPN monitoring group is enabled.
- (Optional) Run trigger unblock-delay max-delay-time
The maximum hold-off time for unblocking the service VSI PWs is set.
- Run binding pw ldp vsi vsi-name peer peer-ip pw-id pw-id encapsulation { vlan | ethernet }
The protocol VSI PWs are bound to the L2VPN monitoring group.
- (Optional) Run binding-pw-up trigger unblock-delay delay-time
The hold-off time for unblocking the service VSI PWs after the protocol VSI PWs bound to the L2VPN monitoring group go Up is set.
- Run commit
The configuration is committed.
- Configure service VSI PWs in LDP mode to track the L2VPN monitoring group.
- Run system-view
The system view is displayed.
- Run vsi vsi-name [ static ]
The view of a service VSI is displayed.
- Run pwsignal ldp
LDP is configured as the PW signaling protocol, and the VSI-LDP view is displayed.
- Run peer peer-address [ negotiation-vc-id vc-id ] pw pw-name
A VSI peer is configured.
- Run track monitor-group group-name
The service VSI PW is configured to track the L2VPN monitoring group. This step must be performed on both SPEs.
- Run commit
The configuration is committed.
- Configure service VSI PWs in BGP-AD mode to track the L2VPN monitoring group.
- Run system-view
The system view is displayed.
- Run vsi vsi-name [ static ]
The view of a service VSI is displayed.
- Run bgp-ad
The PW establishment mode of the VSI is set to BGP-AD, and the VSI BGP-AD view is displayed.
- Run peer peer-address pw pw-name
A PW is created, and the PW view is displayed.
- Run track monitor-group group-name
The service VSI PW is configured to track the L2VPN monitoring group. This step must be performed on both SPEs.
- Run commit
The configuration is committed.