The out-delay command configures a delay for sending Update packets to all BGP peers.
The undo out-delay command deletes the configured delay value.
The default delay value is 0, indicating that the intermediate device on the primary path sends Update packets without a delay.
| Parameter | Description | Value |
|---|---|---|
| delay-value | Specifies the delay for sending Update packets. | The value is an integer that ranges from 0 to 3600, in seconds. |
Usage Scenario
In a scenario with both primary and backup routes, traffic may be lost after it switches back to the primary path. Use a VPN FRR scenario as an example. PE3 and CE2 connect both to PE1 and PE2. The primary path is PE3 -> PE1 -> CE2, and the backup path is PE3 -> PE2 -> CE2. CE2 uses BGP to communicate with PE1 and PE2. FRR is configured on PE3. If PE1 restarts or the link between PE3 and PE1 fails, traffic switches from the primary path to the backup path. After the primary path recovers, traffic switches back to the primary path. If PE3 completes refreshing forwarding entries before PE1 does, PE1 may temporarily fail to forward traffic from PE3, and packet loss may occur. The severity of packet loss is proportional to the number of routes stored on PE1.
To solve this problem, run the out-delay command on PE1 to configure a delay for sending Update packets. An appropriate delay ensures that traffic switches back to the primary path after PE1 completes refreshing forwarding entries.
To configure a delay for sending Update packets to all BGP peers, run the out-delay command. To configure a delay for sending Update packets to a specified BGP peer or peer group, run the peer out-delay command.
Precautions
If you run the peer out-delay command more than once, the latest configuration overrides the previous one.
If the out-delay and peer route-update-interval commands are both configured, only the out-delay command takes effect.
If a network has high route convergence requirements, do no use the out-delay command.