3Com Switch 8800 Configuration Guide Chapter 20 Integrated IS-IS Configuration
20-23
By default, SPF calculation is not divided into slices but runs to the end once, which can
also be implemented by setting the seconds argument to 0.
After slice calculation is set, the routes that are not processed once will be calculated in
one second.
Normally, the user is not recommended to modify the default configuration. When the
number of routes is between 150,000 and 200,000, it is recommended to set the
seconds argument to 1, that is, the duration time for SPF calculation each time is 1
second.

III. Setting SPF to release CPU actively

To prevent SPF calculation from occupying the system resources for a long time, which
affects the response speed of the console, SPF can be set to automatically release the
system CPU resources after processing a certain number of routes and the
unprocessed routes will be calculated in one second.
Perform the following configuration in IS-IS view.
Table 20-32 Set SPF to release CPU actively
Operation Command
Specify the number of routes to process
before releasing CPU spf-delay-interval number
Restore the default configuration undo spf-delay-interval
By default, CPU is released once when every 5000 routes are processed by the SPF of
IS-IS.
20.2.24 Enabling/Disabling the Interface to Send Packets
To prevent the IS-IS routing information from being obtained by some router in a certain
network, the silent-interface command can be used to prohibit sending IS-IS packets
via the interface connecting with the router.
Perform the following configuration in IS-IS view.
Table 20-33 Enable/Disable the interface to send IS-IS packets
Operation Command
Disable the interface to send IS-IS
packets
silent-interface silent-interface-type
silent-interface-number
Enable the interface to send IS-IS
packets
undo silent-interface silent-interface-type
silent-interface-number
By default, the interface is allowed to receive and send IS-IS packets.