Huawei Quidway NetEngine80E Configuration Manual page 856

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
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Changing timer values using the timer command or the peer timer command interrupts BGP
peer relationships between routers. Therefore, exercise caution before changing the value of a
timer.
Keepalive and hold timers can be configured either for all peers or peer groups, or for a specific
peer or peer group. Keepalive and hold timers configured for a specific peer take precedence
over those configured for the peer group of this peer. In addition, Keepalive and hold timers
configured for a specific peer or peer group take precedence over those configured for all peers
or peer groups.
Procedure
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Issue 02 (2014-09-30)
If short Keepalive time and holdtime are set, BGP can detect a link fault quickly. This
speeds up BGP network convergence, but increases the number of Keepalive messages on
the network and loads of routers, and consumes more network bandwidth resources.
If long Keepalive time and holdtime are set, the number of Keepalive messages on the
network is reduced. This reduces loads of routers. If the Keepalive time is too long, BGP
is unable to detect link status changes in a timely manner. This is unhelpful for
implementing rapid BGP network convergence and may cause many packets to be lost.
NOTICE
Configure BGP timers for all peers or peer groups.
Perform the following steps on a BGP router:
1. Run:
system-view
The system view is displayed.
2. Run:
bgp { as-number-plain | as-number-dot }
The BGP view is displayed.
3. Run:
timer keepalive keepalive-time hold hold-time [ min-holdtime min-
holdtime ]
BGP timers are configured.
The proper maximum interval at which Keepalive messages are sent is one third the
holdtime and is not less than one second. If the holdtime is not set to 0, it is 3s at least.
By default, the keepalive-time value is 60s and the hold-time value is 180s.
NOTE
Setting the Keepalive time to 20s is recommended. If the Keepalive time is smaller than 20s,
sessions between peers may be closed.
When setting values of keepalive-time and hold-time, note the following points:
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8 BGP Configuration
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