Setting the Interval for Sending Hello Packets
Context
Hello packets are commonly used. They are periodically sent on OSPF interfaces to establish and maintain neighbor relationships. The intervals set on interfaces that need to establish an OSPF neighbor relationship need to be the same. Otherwise, the interfaces cannot establish the OSPF neighbor relationship.
Procedure
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The OSPF interface view is displayed.
- 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.
The mode switching function takes effect when the interface only has attribute configurations (for example, shutdown and description configurations). Alternatively, if configuration information supported by both Layer 2 and Layer 3 interfaces exists (for example, mode lacp and lacp system-id configurations), no configuration that is not supported after the working mode of the interface is switched can exist. If unsupported configurations exist on the interface, delete the configurations first and then run the undo portswitch command.
If many Ethernet interfaces need to be switched to Layer 3 mode, run the undo portswitch batch interface-type { interface-number1 [ to interface-number2 ] } &<1-10> command in the system view to switch these interfaces to Layer 3 mode in batches.
- Run ospf timer hello interval [ conservative ]
The interval for sending Hello packets is set on the OSPF interface.
By default, the interval for sending Hello packets on a P2P or broadcast interface is 10s; the interval for sending Hello packets on a P2MP or NBMA interface is 30s; the dead time of the OSPF neighbor on an interface is four times the interval for sending Hello packets on the same interface.
To speed up OSPF convergence in the case of a link failure, you are advised to configure BFD for OSPF. For details, see Configuring BFD for OSPF. If the remote end does not support BFD for OSPF or you do not want to configure BFD for OSPF, specify conservative when you run the ospf timer hello command. The conservative mode is recommended so that the value of the dead timer configured using the ospf timer dead command takes effect even when the value is less than 10s. Otherwise, if the actual dead timer that takes effect due to the protection mechanism of a device is greater than 10s, services may be affected.
The interval must be longer than or equal to the active/standby switchover period. Otherwise, a protocol intermittent interruption may occur during the switchover. The default interval for sending Hello packets is recommended. - Run commit
The configuration is committed.
