H3C Technologies H3C S5560 Series Switches - Manual (Page 168)

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Step Command Remarks
4. Specify the maximum length
of received LSPs.
lsp-length receive size
By default, the maximum length
of received LSPs is 1497 bytes.
Enabling LSP flash flooding
Changed LSPs can trigger SPF recalculation. To advertise the changed LSPs before the router recalculates
routes for faster network convergence, enable LSP flash flooding.
To enable LSP flash flooding:
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 flash
flooding.
flash-flood [ flood-count flooding-count |
max-timer-interval flooding-interval | [ level-1 |
level-2 ] ] *
By default, LSP flash
flooding is disabled.
Enabling LSP fragment extension
Perform this task to enable IS-IS fragment extension for an IS-IS process. The MTUs of all interfaces
running the IS-IS process must not be less than 512. Otherwise, LSP fragment extension does not take
effect.
To enable LSP fragment extension:
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: