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Configuring a DIS priority for an interface
On an IS-IS broadcast network, you must elect a router as the DIS at a routing level. You can specify a
DIS priority at a level for an interface. The greater the interface’s priority, the more likely it becomes the
DIS. If multiple routers in the broadcast network have the same highest DIS priority, the router with the
highest MAC address becomes the DIS.
To specify a DIS priority for an interface:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Specify a DIS priority for the
interface.
isis dis-priority
value
[
level-1
|
level-2
]
Optional.
64 by default.
Disabling an interface from sending or receiving IS-IS packets
After being disabled from sending or receiving hello packets, an interface cannot form a neighbor
relationship, but can advertise directly connected networks in LSPs through other interfaces. This can save
bandwidth and CPU resources, and ensures other routers know networks directly connected to the
interface.
To disable an interface from sending and receiving IS-IS packets:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Disable the interface from
sending and receiving IS-IS
packets.
isis silent
Not disabled by default.
Enabling an interface to send small hello packets
IS-IS messages cannot be fragmented at the IP layer because they are directly encapsulated into frames.
Any two IS-IS neighboring routers must negotiate a common MTU. To avoid sending big hellos for saving
bandwidth, enable the interface to send small hello packets without CLVs.
To enable an interface to send small hello packets:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Enable the interface to send
small hello packets without
CLVs.
isis small-hello
Standard hello packets are sent by
default.
