CCNA LAB - 4.3 IP Routing – OSPF


LAB 4-3: IP Routing – OSPF


You are the network administrator at Ranet, and have to config the routers both Ranet-HQ and Ranet-BR to make the connection throughout Ranet network and with the Internet.
So all you have to do are:
(Config via console of each router.)

1. Enable and set IP address on LAN interface of each router to be the last assignable IP of each subnet.

2. Enable serial interface on each router and set IP address on each interface as:

- s0/0/0 on Ranet-BR: last IP of 128.0.6.156/30
- s0/0/0 on Ranet-HQ: first IP of 128.0.6.156/30
- s0/1/0 on Ranet-HQ: last IP of 128.0.6.92/30
all serial interface use HDLC as encapsulation protocol and do not forget to set clock rate at 64 kbps on Ranet-BR side.

3. Set OSPF as routing protocol on each router to let Host1 connect to Host2 in the condition that:

- Use Process ID: 1 for Ranet-HQ and Process ID: 100 for Ranet-BR
- Set RouterID of Ranet-HQ to be 1.1.0.1, and set to be 1.1.1.1 for Ranet-BR

4. Set default route on each router to let both Host1 and Host2 be able to connect to the Online Server
(203.87.129.95) in the internet.

------------------------------------- End ----------------------------------

Solution:

Ranet-HQ config:
(copy & paste these commands to Ranet-HQ router)

en
conf t
int fa0/0
no sh
ip add 128.0.6.142 255.255.255.240
int  s0/0/0
no sh
ip add 128.0.6.157 255.255.255.252
int s0/1/0
no sh
ip add 128.0.6.94 255.255.255.252
exit
int loopback 0
ip add 1.1.0.1 255.255.255.0
exit

router ospf 1
network 128.0.6.128 0.0.0.15 area 0
network 128.0.6.156 0.0.0.3 area 0
exit
ip route 0.0.0.0 0.0.0.0 se0/1/0
end

Ranet-HQ#sh ip protocol

Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 1.1.0.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
128.0.6.128 0.0.0.15 area 0
128.0.6.156 0.0.0.3 area 0
Routing Information Sources:
Gateway Distance Last Update
Distance: (default is 110)

Ranet-HQ#copy run start
Destination filename [startup-config]?
Building configuration...
[OK]

Ranet-HQ#

Ranet-BR config:
(copy & paste these commands to Ranet-BR router)


en
conf t
int fa0/0
no sh
ip add 128.0.6.150 255.255.255.248
int s0/0/0
no sh
clock rate 64000
ip add 128.0.6.158 255.255.255.252
exit
int loopback 0
ip add 1.1.1.1 255.255.255.0
exit

router ospf 100
network 128.0.6.144 0.0.0.7 area 0
network 128.0.6.156 0.0.0.3 area 0
exit

ip route 0.0.0.0 0.0.0.0 se0/0/0
end

Ranet-BR#sh ip protocol

Routing Protocol is "ospf 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 1.1.1.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
ART-CNA-003-L43
Maximum path: 4
Routing for Networks:
128.0.6.144 0.0.0.7 area 0
128.0.6.156 0.0.0.3 area 0
Routing Information Sources:
Gateway Distance Last Update
128.0.6.157 110 00:00:20
Distance: (default is 110)

Ranet-BR#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route

Gateway of last resort is 0.0.0.0 to network 0.0.0.0

1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
128.0.0.0/16 is variably subnetted, 3 subnets, 3 masks
O 128.0.6.128/28 [110/782] via 128.0.6.157, 00:00:29, Serial0/0/0
C 128.0.6.144/29 is directly connected, FastEthernet0/0
C 128.0.6.156/30 is directly connected, Serial0/0/0
S* 0.0.0.0/0 is directly connected, Serial0/0/0

Ranet-BR#copy run start
Destination filename [startup-config]?
Building configuration...
[OK]
Ranet-BR#


----------------------- The End ---------------------


Everything is OK.

You can view and download this solution here.


Leave a comment

3 Comments.

  1. Hi there and thanks for your labor. I am new to networking studying for my CCNA and thought I was good at subnetting until now! ;-) Anyhow, I have a question about the subnetting on the LAN side of the routers. Take RanetBR for example: Doesn't /29 mean there will be 8 hosts available on that network? So with a network address of 128.0.6.148, the broadcast address would be 128.0.6.155, thus the last assignable IP is 128.0.6.154, right? I tried this and as you might predict it said that that address overlapped with the WAN between the routers. Can you tell me where my reasoning is wrong? Thanks. IO thought the same could go for RanetHQ too but I get the same error. Appreciate any help you can offer.

  2. Your correct in /29 has 8 host bits but they make you think a bit about the network address for that subnet. The network address actually starts at 128.0.6.144 /29 making the broadcast 128.0.6.151 and the last assignable host as 128.0.6.150

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