Controlling Spf Calculation Interval; Configuring Convergence Priorities For Specific Routes - HP 6125XLG Configuration Manual

Step
1. Enter system view.
2. Enter IS-IS view.
3. Enable LSP fragment
extension.
4. Configure a virtual system
ID.

Controlling SPF calculation interval

Based on the LSDB, an IS-IS router uses the SPF algorithm to calculate the shortest path tree with itself
being the root, and uses the shortest path tree to determine the next hop to a destination network. By
adjusting the SPF calculation interval, you can prevent bandwidth and router resources from being over
consumed due to frequent topology changes.
When network changes are not frequent, the minimum-interval is adopted. If network changes become
frequent, the SPF calculation interval is incremented by incremental-interval × 2
calculation times) each time a calculation occurs until the maximum-interval is reached.
To control SPF calculation interval:
Step
1. Enter system view.
2. Enter IS-IS view.
3. Configure the SPF
calculation interval.

Configuring convergence priorities for specific routes

A topology change causes IS-IS routing convergence. To improve convergence speed, you can assign
different convergence priorities to specific IS-IS routes, including critical, high, medium, and low. The
higher the convergence priority, the faster the convergence speed.
IS-IS host routes have the medium convergence priority.
To assign convergence priorities to specific IS-IS routes:
Command
system-view
isis [ process-id ] [ vpn-instance
vpn-instance-name ]
lsp-fragments-extend [ level-1 |
level-1-2 | level-2 ]
virtual-system virtual-system-id
Command
system-view
isis [ process-id ] [ vpn-instance
vpn-instance-name ]
timer spf maximum-interval
[ minimum-interval [ incremental-interval ] ]
127
Remarks
N/A
N/A
By default, this feature is disabled.
By default, no virtual system ID is
configured.
Configure at least one virtual system to
generate extended LSP fragments.
n-2 (n is the number of
Remarks
N/A
N/A
By default:
•
The maximum interval is 5
seconds.
•
The minimum interval is 50
milliseconds.
•
The incremental interval is
200 milliseconds.