Setting The Spf Calculation Interval - Huawei Quidway NetEngine80E Configuration Manual

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing

7.16.4 Setting the SPF Calculation Interval

To improve the fault location efficiency on an IS-IS network and prevent SPF calculation from
consuming excessive system resources, set the SPF calculation interval to a proper value.
Context
A network change always triggers IS-IS to perform SPF calculation. Frequent SPF calculation
will consume excessive CPU resources, affecting services.
To solve this problem, configure an intelligent timer to control the interval for SPF calculation.
For example, to speed up IS-IS route convergence, set the interval for SPF calculation to a small
value, and set the interval to a large value after the IS-IS network becomes stable.
Procedure
Step 1 Run:
system-view
The system view is displayed.
Step 2 Run:
isis [ process-id ]
The IS-IS view is displayed.
Step 3 Run:
timer spf max-interval [ init-interval [ incr-interval ] ]
The SPF intelligent timer is configured.
The intelligent timer changes as follows:
l The delay for the first SPF calculation is determined by init-interval; the delay for the second
l If incr-interval is not specified, the delay in SPF calculation for the first time is determined
l When only max-interval is specified, the intelligent timer functions as an ordinary one-time
----End
7.16.5 Configuring Convergence Priorities for IPv6 IS-IS Routes
If some IS-IS routes need to be converged by preference to minimize adverse impacts on services,
configure those routes to have the highest convergence priority.
Issue 02 (2014-09-30)
SPF calculation is determined by incr-interval. From the third time on, the delay in SPF
calculation increases twice every time until the delay reaches the value specified by max-
interval. After the delay remains at the value specified by max-interval for three times or the
IS-IS process is restarted, the delay decreases to the value specified by init-interval.
by init-interval. From the second time on, the delay in SPF calculation is determined by max-
interval. After the delay remains at the value specified by max-interval for three times or the
IS-IS process is restarted, the delay decreases to the value specified by init-interval.
triggering timer.
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