Before You Start - Huawei Quidway NetEngine80E Configuration Manual

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing

8.14.1 Before You Start

Before adjusting the BGP network convergence speed, familiarize yourself with the usage
scenario, complete the pre-configuration tasks, and obtain the data required for the configuration.
Usage Scenario
BGP is used to transmit routing information on large-scale networks. Frequent network changes
affect the establishment and maintenance of BGP peer relationships and the BGP network
convergence speed.
BGP route dampening and triggered update suppress frequent route changes to an extent, but
cannot minimize the impact of network flapping on BGP connections.
To suppress BGP network flapping and speed up BGP network convergence, configure BGP
timers, disable rapid EBGP connection reset, enable BGP tracking and slow peer detection.
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Issue 02 (2014-09-30)
ConnectRetry timer
A ConnectRetry timer is used to set an interval between BGP attempts to initiate TCP
connections. After BGP initiates a TCP connection, the ConnectRetry timer will be stopped
if the TCP connection is established successfully. If the first attempt to establish a TCP
connection fails, BGP tries again to establish the TCP connection after the ConnectRetry
timer expires.
You can accelerate or slow down the establishment of BGP peer relationships by changing
the BGP ConnectRetry interval. For example, if the ConnectRetry interval is reduced, BGP
will wait less time before retrying to establish a TCP connection when the previous attempt
fails, which speeds up TCP connection establishment. If a BGP peer flaps constantly, the
ConnectRetry interval can be increased to suppress route flapping caused by BGP peer
flapping, which speeds up route convergence.
BGP Keepalive and hold timers
BGP uses Keepalive messages to maintain BGP peer relationships and monitor connection
status.
After establishing a BGP connection, two peers send Keepalive messages periodically to
each other to detect the BGP connection status. If the router does not receive any Keepalive
message or any other types of packets from the peer within the hold time, the router
considers the BGP connection interrupted and terminates the BGP connection.
BGP MinRouteAdvertisementIntervalTimer
BGP does not periodically update a routing table. When BGP routes change, BGP updates
the changed BGP routes in the BGP routing table by sending Update messages. If a route
changes frequently, to prevent the router from sending Update messages upon every
change, set the interval at which Update messages are sent.
Rapid EBGP connection reset
Rapid EBGP connection reset is enabled by default so that EBGP can quickly detect the
status of interfaces used to establish EBGP connections. If the interface status changes
frequently, disable rapid EBGP connection reset. After rapid EBGP connection reset is
disabled, direct EBPG sessions will not be reestablished and deleted as interface alternates
between Up and Down, which speeds up network convergence.
BGP peer tracking
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8 BGP Configuration

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