HPE FlexNetwork HSR6800 Configuration Manual page 156

Step
Enter IS-IS view.
2.
Enable LSP flash
3.
flooding.
Enabling LSP fragment extension
After LSP fragment extension is enabled for an IS-IS process, the MTUs of all the interfaces running
the IS-IS process must not be less than 512. Otherwise, LSP fragment extension will not take effect.
At least one virtual system must be configured for the router to generate extended LSP fragments.
An IS-IS process allows a maximum of 50 virtual systems.
To enable LSP fragment extension:
Step
Enter system view.
1.
Enter IS-IS view.
2.
Enable LSP fragment
3.
extension and specify
the working mode.
Configure a virtual
4.
system ID.
Limiting LSP flooding
In well-connected ATM, FR and NBMA networks, many P2P links exist.
meshed network, where Routers A, B, C and D run IS-IS. When Router A generates an LSP, it floods
the LSP out of GigabitEthernet 2/1/1, GigabitEthernet 2/1/2 and GigabitEthernet 2/1/3. After
receiving the LSP from GigabitEthernet 2/1/3, Router D floods it out of GigabitEthernet 2/1/1 and
GigabitEthernet 2/1/2 to Router B and Router C. However, Router B and Router C have already
received the LSP from Router A. LSP flooding consumes extra bandwidth.
Figure 47 Network diagram of a fully meshed network
To avoid this, configure some interfaces as a mesh group, configure the blocked interfaces, or both.
•
After receiving an LSP, a member interface in a mesh group floods it out of the interfaces that do
not belong to the mesh group.
•
If an interface is blocked, it does not send LSPs unless the neighbor sends LSP requests to it.
Command
isis [ process-id ] [ vpn-instance
vpn-instance-name ]
flash-flood [ flood-count flooding-count |
max-timer-interval flooding-interval | [ level-1 |
level-2 ] ] *
Command
system-view
isis [ process-id ] [ vpn-instance
vpn-instance-name ]
lsp-fragments-extend [ [ level-1 | level-1-2
| level-2 ] | [ mode-1 | mode-2 ] ] *
virtual-system virtual-system-id
144
Remarks
N/A
Not enabled by
default.
Remarks
N/A
N/A
Not enabled by default.
Not configured by default.
Figure 47 shows a fully