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Tuning and optimizing IS-IS networks
Configuration prerequisites
Before you tune and optimize IS-IS networks, complete the following tasks:
•
Configure IP addresses for interfaces, and make adjacent nodes can reach each other at the
network layer.
•
Enable IS-IS.
Specifying intervals for sending IS-IS hello and CSNP packets
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Specify the interval for
sending hello packets.
isis timer hello
seconds
[
level-1
|
level-2
]
Optional.
10 seconds by default.
4.
Specify the interval for
sending CSNP packets on the
DIS of a broadcast network.
isis timer csnp
seconds
[
level-1 |
level-2
]
Optional.
10 seconds by default.
NOTE:
The interval between hello packets sent by the DIS is 1/3 the hello interval set with the
isis timer hello
command.
Specifying the IS-IS hello multiplier
If a neighbor receives no hello packets from the router within the advertised hold time, it considers the
router down and recalculates the routes. The hold time is the hello multiplier multiplied by the hello
interval.
On a broadcast link, Level-1 and Level-2 hello packets are advertised separately; therefore, you need to
set a hello multiplier for each level.
On a P2P link, Level-1 and Level-2 hello packets are advertised in P2P hello packets, so you do not need
to specify Level-1 or Level-2.
To specify the IS-IS hello multiplier:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Specify the number of hello packets a
neighbor must miss before declaring
the router is down.
isis timer holding-multiplier
value
[
level-1
|
level-2
]
Optional.
3 by default.
