HP 6125XLG R2306-HP 6125XLG Blade Switch Layer 3 - IP Routing Configuration Gu - Page 138

Controlling SPF calculation interval, Configuring convergence priorities for specific routes

Page 138 highlights

Step 1. Enter system view. 2. Enter IS-IS view. 3. Enable LSP fragment extension. Command system-view isis [ process-id ] [ vpn-instance vpn-instance-name ] lsp-fragments-extend [ level-1 | level-1-2 | level-2 ] 4. Configure a virtual system ID. virtual-system virtual-system-id 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. 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 × 2n-2 (n is the number of 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. Command Remarks system-view N/A isis [ process-id ] [ vpn-instance vpn-instance-name ] N/A timer spf maximum-interval [ minimum-interval [ incremental-interval ] ] By default: • The maximum interval is 5 seconds. • The minimum interval is 50 milliseconds. • The incremental interval is 200 milliseconds. 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: 127

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127
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter IS-IS view.
isis
[
process-id
] [
vpn-instance
vpn-instance-name
]
N/A
3.
Enable LSP fragment
extension.
lsp-fragments-extend
[
level-1
|
level-1-2
|
level-2
]
By default, this feature is disabled.
4.
Configure a virtual system
ID.
virtual-system
virtual-system-id
By default, no virtual system ID is
configured.
Configure at least one virtual system to
generate extended LSP fragments.
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
n-2
(n is the number of
calculation times) each time a calculation occurs until the
maximum-interval
is reached.
To control SPF calculation interval:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter IS-IS view.
isis
[
process-id
] [
vpn-instance
vpn-instance-name
]
N/A
3.
Configure the SPF
calculation interval.
timer spf
maximum-interval
[
minimum-interval
[
incremental-interval
] ]
By default:
The maximum interval is 5
seconds.
The minimum interval is 50
milliseconds.
The incremental interval is
200 milliseconds.
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: