Configuring the OSPF GR Helper
Applicable Environment
Graceful Restart (GR) is a technology used to ensure normal traffic forwarding and non-stop forwarding of key services during the restart of routing protocols. GR is one of high availability (HA) technologies, comprising a set of comprehensive techniques, such as fault-tolerant redundancy, link protection, faulty node recovery, and traffic engineering. As a fault-tolerant redundancy technology, GR is widely used to ensure non-stop forwarding of key services during active/standby switchover and system upgrade.
The CloudEngine 12800 and 12800E series switches support only the GR Helper role.
Pre-configuration Tasks
Before configuring OSPF GR, complete the following tasks:
Configuring IP addresses for interfaces to ensure that neighboring nodes are reachable at the network layer
Procedure
- Run system-view
The system view is displayed.
- Run ospf [ process-id ]
The OSPF view is displayed.
- Run opaque-capability enable
The opaque LSA capability is enabled.
Opaque LSAs provide the following generic mechanisms for OSPF extension:OSPF uses Type 9 LSAs to support GR.
OSPF uses Type 10 LSAs to support TE.
Therefore, before configuring OSPF GR, you need to enable the opaque LSA capability using the opaque-capability enable command.
- Configure GR session parameters on the helper.
IETF mode and non-IETF mode are mutually exclusive.
- Configure GR session parameters on the helper in IETF mode.
Run graceful-restart helper-role ignore-external-lsa
The helper does not check AS external LSAs.
By default, the helper checks AS-external LSAs.
Run graceful-restart helper-role planned-only
The helper is configured to support only planned GR.
By default, the helper supports both planned GR and unplanned GR.
Choose either of the following configuration as required:
Configure a basic ACL rule.
Run graceful-restart [ helper-role { { acl-number acl-number | acl-name acl-name } * } | never } ]GR session parameters on the helper are configured.
Configure an IP prefix list.
Run graceful-restart [ helper-role { { ip-prefix ip-prefix-name * } | never } ]
GR session parameters on the helper are configured.
Enable GR session on the helper in non-IETF mode.
Run graceful-restart non-ietf
GR Helper in non-IETF mode is enabled.
- Configure GR session parameters on the helper in IETF mode.