3Com Switch 8800 Configuration Guide
Chapter 20 Integrated IS-IS Configuration
20-22
Perform the following configuration in IS-IS view.
Table 20-29
Set Lifetime of LSP
Operation
Command
Set lifetime of LSP
timer lsp-max-age seconds
Restore the default LSP lifetime
undo
timer lsp-max-age
By default, LSP can live for 1200 seconds (20 minutes).
20.2.23 Setting Parameters Related to SPF
I. Setting SPF calculation interval
When IS-IS LSDB changes, the router will compute the shortest path again. However,
the immediate calculation upon every change will occupy too many resources and
affect the efficiency of the router. In the case that SPF computing interval is set, when
LSDB changes, SPF algorithm will be run after the SPF interval times out.
Perform the following configuration in IS-IS view.
Table 20-30
Set SPF calculation interval
Operation
Command
Set SPF calculation interval
timer spf second
[
level-1
|
level-2
]
Restore default SPF calculation interval
undo
timer spf
[
level-1
|
level-2
]
If the level is not specified, it defaults to setting the SPF calculation interval of Level-1.
By default, SPF calculation runs every 10 seconds.
II. Setting SPF calculation in slice
When there is a large number of routes in the routing table (over 150,000), SPF
calculation of IS-IS may occupy the system resources for a long time. To prevent such a
case, SPF calculation can be set to perform in slice.
Perform the following configuration in IS-IS view.
Table 20-31
Set SPF calculation in slice
Operation
Command
Set the duration of one cycle in second
of SPF calculation
spf-slice-size
seconds
Restore the default configuration
undo spf-slice-size