Disabling Fast Reset Of Ebgp Connections - Huawei Quidway NetEngine80E Configuration Manual

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
nexthop recursive-lookup non-critical-event route-update-timer route-update-timer
[ route-update-number route-update-number ]
The rate at which BGP updates routes in response to non-critical iteration changes is configured.
By default, the rate at which BGP updates routes in response to non-critical iteration changes is
not configured.
If route-update-number route-update-number is configured, the number of routes that are
updated each second is route-update-number/route-update-timer. For example, route-update-
timer is 5 and route-update-number is 1000, the number of routes that are updated each second
is 200.
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8.14.6 Disabling Fast Reset of EBGP Connections

Disabling rapid EBGP connection reset can prevent repeated reestablishment and deletion of
EBGP sessions in the event of route flapping. This speeds up BGP network convergence.
Context
Rapid EBGP connection reset is enabled by default. This allows BGP to immediately respond
to a fault on an interface and delete the direct EBGP sessions on the interface without waiting
for the hold timer to expire and implements rapid BGP network convergence.
If the status of an interface used to establish an EBGP connection changes frequently, the EBGP
session will be deleted and reestablished repeatedly, causing network flapping. Rapid EBGP
connection reset can be disabled in such a situation. BGP will delete direct EBGP sessions on
the interface until the hold timer expires. This suppresses BGP network flapping, helps to
implement rapid BGP network convergence, and reduces network bandwidth consumption.
Perform the following steps on a BGP router.
Procedure
Step 1 Run:
system-view
The system view is displayed.
Issue 02 (2014-09-30)
NOTE
When many BGP routes are iterated to one next hop and a non-critical iteration change occurs on the next
hop, if the nexthop recursive-lookup non-critical-event route-update-timer command is configured,
the BGP route convergence is slowed down. Before BGP updates all routes associated with the next hop,
the IP routing table shows iteration information before the update. However, the forwarding entries have
been updated, and traffic is forwarded along the correct path.
The nexthop recursive-lookup non-critical-event route-update-timer command does not take effect to
critical iteration changes on a next hop, and for example, the reachability of the next hop changes due to
interface flapping.
NOTE
Rapid EBGP connection reset enables BGP to quickly respond to interface faults but does not enable BGP
to quickly respond to interface recovery. After the interface recovers, BGP uses its state machine to restore
relevant sessions.
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8 BGP Configuration
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