OSPF Lab on GNS3 for ICND1:
In network diagram you can find
the three router R1, R2 and R3. R1 and R2 are already
configured with IP addresses and OSPF area 0. You need to perform the following tasks
and configurations:
- Configure last available IP address of f0/0 of R3 with first usable subnet 192.168.224.0/28
- Configure first available IP address for S1/0 with second usable subnet from the network 192.168.224.0/28.
- Configure OSPF with area 0 on R3 so that R3 can properly communicate with R1 and R2
Solution:
You can practice this LAB on GNS3 by downloading R1 and R2
configuration other necessary detail for GNS3 configuration are as under:
Router IOS= 7200 series (you can download it from here)
GNS3 version= GNS3 1.0 beta2
Router module/slot used: slot1=c7200-IO-2FE, slot2=PA-8T
(Note: for quick configuration you can download these
text files and can copy paste these configuration into your GNS3 router)
Configure f0/0 with first useable subnet from 192.168.224.0/28:
For finding the first useable
subnet you can consider the following table:
Subnetting for 192.168.224.0/28
|
|||||||||
Bit# in 4th octet
|
25
|
26
|
27
|
28
|
29
|
30
|
31
|
32
|
|
IP ranges/ increment
|
128
|
64
|
32
|
16
|
8
|
4
|
2
|
1
|
|
From above table you can find following
subnets with the increment of 16 for 192.168.224.0/28.
Subnet1= 192.168.224.0 to 192.168.224.15 (Subnet ID=192.168.224.0)
Subnet2= 192.168.224.16 to 192.168.224.31
Subnet3= 192.168.224.32 to 192.168.224.47
.
.
.
Since we need to assign last available
IP address from subnet1, therefore we have the last IP address= 192.168.224.14
R3> enable
R3# config t
R3(config)# int f0/0
R3(config-if)# ip address
192.168.224.14 255.255.255.240
R3(config-if)# no shut
2. Configure first available IP address to S1/0 with second usable subnet from the network 192.168.224.0/28:
For above table we have already
find that second subnet is 192.168.224.16 to 192.168.224.31 with first IP
address=192.168.224.17
R3(config)# int S1/0
R3(config-if)# ip address
192.168.224.17 255.255.255.240
R3(config-if)# no shut
3. Advertise both interface of R3 in OSPF:
R3(config)#Router OSPF 1
R3(config-router)#network
192.168.224.0 0.0.0.15 area 0
R3(config-router)#network
192.168.224.16 0.0.0.15 area 0
Results and testing:
After the correct configuration you should have the
following output for “show IP route” command:
After the configuration you should have successful ping
to 192.168.200.1
If you have any trouble/issue with R3 configuration you
can also download R3 configuration from here and
can compare it to your configuration.
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