R21xx-HP FlexFabric 11900 Layer 3 IP Routing Configuration Guide

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If such a change occurs frequently, excessive LSPs are generated, consuming a large amount of
router resources and bandwidth. To solve the problem, you can adjust the LSP generation interval.
When network changes are not frequent, the minimum-interval is adopted. If network changes
become frequent, the LSP generation interval is incremented by incremental-interval × 2
n-2
(n is the
number of calculation times) each time a generation occurs until the maximum-interval is reached.
To specify the LSP refresh interval and generation interval:
Ste
p
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. Specify the LSP refresh
interval.
timer lsp-refresh seconds
By default, the LSP refresh
interval is 900 seconds.
4. Specify the LSP
generation interval.
timer lsp-generation maximum-interval
[ minimum-interval [ incremental-interval ] ]
[ level-1 | level-2 ]
By default:
• The maximum interval is 2
seconds.
• The minimum interval is 0
milliseconds.
• The incremental interval is
0 milliseconds.
3. Specify LSP sending intervals.
If a change occurs in the LSDB, IS-IS advertises the changed LSP to neighbors. You can specify the
minimum interval for sending such LSPs to control the amount of LSPs on the network.
To configure LSP sending intervals:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enter interface view.
interface interface-type
interface-number
N/A
3. Specify the minimum interval
for sending LSPs and the
maximum LSP number that
can be sent at a time.
isis timer lsp time [ count count ]
By default, the minimum interval is 33
milliseconds, and the maximum LSP
number that can be sent at a time is 5.
Specifying LSP lengths
IS-IS messages cannot be fragmented at the IP layer because they are directly encapsulated in frames.
IS-IS routers in an area must send LSPs smaller than the smallest interface MTU in the area.
If the IS-IS routers have different interface MTUs, HP recommends configuring the maximum size of
generated LSP packets to be smaller than the smallest interface MTU in the area. Otherwise, the routers
must dynamically adjust the LSP packet size to fit the smallest interface MTU, which takes time and affects
other services.
To specify LSP lengths: