Huawei Quidway NetEngine80E Configuration Manual page 884

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
Step 5 (Optional) Prevent path-switchover-triggered packet loss.
In a BGP Auto FRR scenario, if the device on which FRR is configured completes refreshing
forwarding entries before the intermediate device on the primary path does after the primary
path recovers, traffic may be lost after it switches back to the primary path. The severity of packet
loss is proportional to the number of routes stored on the intermediate device. To solve this
problem, perform any of the following operations to prevent path-switchover-triggered packet
loss:
l In the BGP view of the intermediate device on the primary path, run:
l In the BGP view or BGP-IPv4 unicast address family view of the intermediate device on the
l In the BGP view or BGP-IPv4 unicast address family view of the device on which FRR is
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Checking the Configurations
After configuring BGP Auto FRR, you can run the following commands to check the
configurations.
Issue 02 (2014-09-30)
NOTE
On a network with both primary and backup links, the router may also use IP FRR for link protection. BGP
Auto FRR takes effect on a BGP route only when the route fails to match the routing policy specified in
the ip frr command run in the system view because IP FRR takes precedence over BGP Auto FRR.
out-delay delay-value
A delay for sending Update packets to all BGP peers is configured. An appropriate delay
ensures that traffic switches back to the primary path after the intermediate device on the
primary path completes refreshing forwarding entries.
The delay-value value is an integer ranging from 0 to 3600, in seconds. The default delay-
value value is 0, indicating that the intermediate device on the primary path sends Update
packets without a delay. The delay-value value is inversely proportional to the route
convergence performance of the device on which FRR is configured.
primary path, run:
peer { group-name | ipv4-address } out-delay delay-value
A delay for sending Update packets is configured. An appropriate delay ensures that traffic
switches back to the primary path after the intermediate device on the primary path completes
refreshing forwarding entries.
The delay-value value is an integer ranging from 0 to 3600, in seconds. The default delay-
value value is 0, indicating that the intermediate device on the primary path sends Update
packets without a delay. The delay-value value is inversely proportional to the route
convergence performance of the device on which FRR is configured.
configured, run:
route-select delay delay-value
A delay for selecting a route to the intermediate device on the primary path is configured.
An appropriate delay ensures that traffic switches back to the primary path after the
intermediate device completes refreshing forwarding entries.
The delay-value value is an integer ranging from 0 to 3600, in seconds. The default delay-
value value is 0, indicating that the device on which FRR is configured selects a route to the
intermediate device on the primary path without a delay.
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8 BGP Configuration
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