135
To advertise a default route:
Step 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.
Advertise a default
route.
default-route-advertise
[ [
level-1
|
level-1-2
|
level-2
] |
route-policy
route-policy-name
]
*
By default, IS-IS does not advertise
a default route.
Configuring IS-IS route redistribution
Perform this task to redistribute routes from other routing protocols into IS-IS. You can specify a cost for
redistributed routes and specify the maximum number of redistributed routes.
To configure IS-IS route redistribution from other routing protocols:
Step 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.
Redistribute routes from
other routing protocols
or other IS-IS processes.
import-route
protocol
[
process-id
|
all-processes
|
allow-ibgp
] [
cost
cost
|
cost-type
{
external
|
internal
} |
[
level-1
|
level-1-2
|
level-2
] |
route-policy
route-policy-name
|
tag
tag
] *
By default, no route is redistributed.
By default, if no level is specified, this
command redistributes routes into the
Level-2 routing table.
This command redistributes only
active routes. To display active
routes, use the
display ip
routing-table
protocol
command.
4.
(Optional.) Configure
the maximum number of
redistributed Level
1/Level 2 IPv4 routes.
import-route limit
number
The default for this command varies
by device model.
Configuring IS-IS route filtering
You can use an ACL, IP prefix list, or routing policy to filter routes calculated using received LSPs and
routes redistributed from other routing protocols.
Filtering routes calculated from received LSPs
IS-IS saves LSPs received from neighbors in the LSDB, uses the SPF algorithm to calculate the shortest path
tree with itself as the root, and installs the routes to the IS-IS routing table. IS-IS installs the optimal routes
to the IP routing table.
Perform this task to filter calculated routes. Only routes that are not filtered can be added to the IP routing
table. The filtered routes retain in the IS-IS routing table and can be advertised to neighbors.
To filter routes calculated using received LSPs:
