Table of contents
IS-IS Experiment 8: Importing IS-IS Routes
IS-IS Experiment 8: Importing IS-IS Routes
The IS-IS network can import routes of other routing protocols and routes of other IS-IS protocol processes. By default, IS-IS always imports external routes as level-2 routes. However, through manual configuration, external routes can also be imported as level-1 routes. When the IS-IS protocol imports external routes, the cost of the imported routes can be manually configured, and route-policy can be used to filter the imported routes.
Base deployment
R1:
undo ter mo
sys
sysname R1
user-interface console 0
idle-timeout 0 0
int g0/0/1
ip add 192.168.14.1 24
int g0/0/0
ip add 192.168.12.1 24
q
R2:
undo ter mo
sys
sysname R2
user-interface console 0
idle-timeout 0 0
int g0/0/0
ip add 192.168.12.2 24
int g0/0/1
ip add 192.168.23.2 24
q
R3:
undo ter mo
sys
sysname R3
user-interface console 0
idle-timeout 0 0
int loop 0
ip add 3.3.3.3 24
int g0/0/1
ip add 192.168.23.3 24
q
R4:
undo ter mo
sys
sysname R4
user-interface console 0
idle-timeout 0 0
int loop 0
ip add 4.4.4.4 24
int loop 1
ip add 44.44.44.44 24
int g0/0/0
ip add 192.168.14.4 24
q
Configure the OSPF IS-IS protocol, and the R3 loopback interface is placed in the IS-IS protocol through the imported direction
R1:
ospf router-id 1.1.1.1
area 0
net 192.168.14.1 0.0.0.0
q
isis
network-entity 10.0000.0000.0001.00
is-name R1
is-level level-1
int g0/0/0
isis enable
q
R2:
isis
network-entity 10.0000.0000.0002.00
is-name R2
int g0/0/0
isis enable
isis circuit-level level-1
int g0/0/1
isis enable
isis circuit-level level-2
q
R3:
isis
network-entity 20.0000.0000.0003.00
is-name R3
is-level level-2
int g0/0/1
isis enable
q
R4:
ospf router-id 4.4.4.4
area 0
net 192.168.14.4 0.0.0.0
net 4.4.4.4 0.0.0.0
net 44.44.44.44 0.0.0.0
q
========
Introduce external direct route
R3:
isis
import-route direct
<R3>display isis route
By default, IS-IS uses the Level-2 route type to import external routes, the IntCost and ExtCost values of the imported routes are both 0, and the cost type is External
Check the IS-IS routing table on R2
In the routing table, it shows as 74
For the cost of the External type, the calculation method of the cost value in the IP routing table is: 64+ IntCost in the IS-IS routing table+ ExtCost in the IS-IS routing table.
External cost calculation method:
64+ Incost +ExtCost= 64+10+0=74
R1 can ping R3
<R1>ping 3.3.3.3
Import external OSPF routes
On R1, import the OSPF protocol into IS-IS with the cost type as Internal, and change the InCost to 30 when importing, and change it to level-1 when importing
R1：
isis
import-route ospf 1 level-1 cost-type internal cost 30
Check the IS-IS routing table on R2
Imported routes can be seen on R2
========
Use route-policy to control the introduction of routes.
Only 4.4.4.4 of R4 is required to introduce IS-IS
R1:
acl 2000
rule permit source 4.4.4.0 0.0.0.255
route-policy 10 permit node 1
if-match acl 2000
isis
import-route ospf 1 route-policy 10 level-1 cost-type internal cost 30
Check it out on R2, only 4.4.4.4 introduces
========
In order to allow the loopback interfaces of R4 and R3 to ping each other, on R1, distribute the default route to
R1 through OSPF:
ospf
default-route-advertise
Check connectivity
R4:
ping -a 4.4.4.4 3.3.3.3
