HP VPN Firewall Appliances Network Management Configuration Guide

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Each router needs to refresh LSPs generated by itself at a configurable interval and send them to
other routers to prevent valid routes from being aged out. A smaller refresh interval speeds up
network convergence but consumes more bandwidth.
When the network topology changes, for example, a neighbor is down or up, or the interface
metric, system ID, or area ID is changed, the router generates an LSP after a configurable interval.
If such a change occurs frequently, excessive LSPs are generated, consuming a large amount of
router resources and bandwidth. To resolve this issue, you can adjust the LSP generation interval.
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
Optional.
The default interval is 900 seconds.
4. Specify the LSP
generation interval.
timer lsp-generation maximum-interval
[ initial-interval [ second-wait-interval ] ]
[ level-1 | level-2 ]
Optional.
The default interval is 2 seconds.
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.
On a P2P link, IS-IS requires an advertised LSP be acknowledged. If no acknowledgement is
received within a configurable interval, IS-IS will retransmit the LSP.
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 ]
Optional.
By default, the minimum interval is 33
milliseconds, and the maximum LSP number
that can be sent at a time is 5.
4. Specify the LSP
retransmission interval on a
P2P link.
isis timer retransmit
seconds
Optional.
5 seconds by default.
Configure a proper LSP retransmission
interval to avoid unnecessary
retransmissions.
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 this area.