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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
By default, the maximum number of
redistributed Level 1/Level 2 IPv4
routes is not configured.
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:
Step Command Remarks
1. Enter system view.
system-view
N/A