HPE FlexNetwork 5510 HI Series Layer 3 - Ip Routing Configuration Guide

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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 convergence priorities to IS-IS routes. Convergence priority levels are critical, high, medium,
and low. The higher the convergence priority, the faster the convergence speed.
By default, IS-IS host routes have medium convergence priority, and other IS-IS routes have low
convergence priority.
To assign convergence priorities to specific IS-IS routes:
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. Assign convergence
priorities to specific IS-IS
routes.
priority
{
critical
|
high
|
medium
} {
prefix-list
prefix-list-name |
tag
tag-value }
By default, IS-IS routes, except
IS-IS host routes, have the low
convergence priority.
Setting the LSDB overload bit
By setting the overload bit in sent LSPs, a router informs other routers of failures that make it unable
to select routes and forward packets.
When an IS-IS router cannot record the complete LSDB, for example, because of memory
insufficiency, it will calculate wrong routes. To make troubleshooting easier, temporarily isolate the
router from the IS-IS network by setting the overload bit.
To set the LSDB overload bit:

HPE FlexNetwork 5510 HI Series Specifications

General

Brand	HPE
Model	FlexNetwork 5510 HI Series
Category	Switch
Language	English