In this lab, I will show OSPF Multi Area Configuration of 3 Routers
Table of Contents
VLSM
Given Network: 50.0.0.0
Required host on Router 1= 20,00,000
Required host on Router 2= 5,00,000
Required host on Router 3= 1,00,000
R1<=20,00,000
20,00,000<=2n – 2
20,00,000 <=221 – 2
20,00,000<=20,97,152– 2
20,00,000<=20,97,150
Total number of network bits = 32
32 – n = 32 – 21 = 11 (CIDR value of Router 1 i.e. Given network)
i.e. 50.0.0.0/11
N.S.M = 11111111.11100000.00000000.00000000
= 255.224.0.0
Block Size = 256 – N.S.M
= 256 – 224 = 32
Note: Add this block size in given network so that we can get our new network for Router 2.
so the new network is 50.32.0.0/?
Now find FVH, LVH and Broadcast address
| Given Network | 50 | 0 | 0 | 0 |
| First Valid Host-FVH | 50 | 0 | 0 | 1 |
| Last Valid Host-LVH | 50 | 31 | 255 | 254 |
| Broadcast | 50 | 31 | 255 | 255 |
| New Network | 50 | 32 | 0 | 0 |
R2<=5,00,000
5,00,000<=2n – 2
5,00,000<=219 – 2
5,00,000<=5,24,288 – 2
5,00,000<=5,24,286
Total number of network bits = 32
32 – n = 32 – 19 = 13 (CIDR value of Router 3 i.e. New network)
i.e. 50.32.0.0/13
N.S.M = 11111111.11111000.00000000.00000000
= 255.248.0.0
Block Size = 256 – N.S.M
= 256 – 248 = 8
Note: Add this block size in given network so that we can get our new network for Router 3.
so the new network is 50.40.0.0/?
Now find FVH, LVH and Broadcast address
| Given Network | 50 | 32 | 0 | 0 |
| First Valid Host-FVH | 50 | 32 | 0 | 1 |
| Last Valid Host-LVH | 50 | 39 | 255 | 254 |
| Broadcast | 50 | 39 | 255 | 255 |
| New Network | 50 | 40 | 0 | 0 |
R3<=1,00,000
1,00,000<=2n – 2
1,00,000<=217 – 2
1,00,000<=1,31,072 – 2
1,00,000<=1,31,070
Total number of network bits = 32
32 – n = 32 – 17 = 15 (CIDR value of Router 3 i.e. New network)
i.e. 50.40.0.0/15
N.S.M = 11111111.11111110.00000000.00000000
= 255.254.0.0
Block Size = 256 – N.S.M
= 256 – 254 = 2
Note: Add this block size in given network so that we can get our new network for Router 1 and Router 2 (Virtual Network).
so the new network is 50.42.0.0/?
Now find FVH, LVH and Broadcast address
| Given Network | 50 | 40 | 0 | 0 |
| First Valid Host-FVH | 50 | 40 | 0 | 1 |
| Last Valid Host-LVH | 50 | 41 | 255 | 254 |
| Broadcast | 50 | 41 | 255 | 255 |
| New Network | 50 | 42 | 0 | 0 |
Router 1 and Router 2 <= 2 (we required only two IP to connect two routers)
2 <= 2n – 2
2 <= 22 – 2
2 <= 4 – 2
2 <= 2
Total number of network bits = 32
32 – n = 32 – 2 = 30 (CIDR of Virtual network (R1&R2))
i.e. 50.42.0.0/30
N.S.M = 11111111.11111111.11111111.11111100
= 255.255.255.252
Block Size = 256 – N.S.M
= 256 – 252 = 4
Note: Add this block size in given network so that we can get our new network for Router 2 and Router 3 (Virtual Network). so the new network is 50.42.0.4/30?
Now find FVH, LVH and Broadcast address
| Given Network | 50 | 42 | 0 | 0 |
| First Valid Host-FVH | 50 | 42 | 0 | 1 |
| Last Valid Host-LVH | 50 | 42 | 0 | 2 |
| Broadcast | 50 | 42 | 0 | 3 |
| New Network | 50 | 42 | 0 | 4 |
2 and Router 3 <= 2 (we required only two IP to connect two routers)
2 <= 2n – 2
2 <= 22 – 2
2 <= 4 – 2
2 <= 2
Total number of network bits = 32
32 – n = 32 – 2 = 30 (CIDR of Virtual network (R2&R3))
i.e. 50.42.0.4/30
N.S.M = 11111111.11111111.11111111.11111100
= 255.255.255.252
Block Size = 256 – N.S.M
= 256 – 252 = 4
Note: Add this block size in given network so that we can get our new network for Router 4. This network can be used in future.
so the new network is 50.42.0.8/?
Now find FVH, LVH and Broadcast address
| Given Network | 50 | 42 | 0 | 4 |
| First Valid Host-FVH | 50 | 42 | 0 | 5 |
| Last Valid Host-LVH | 50 | 42 | 0 | 6 |
| Broadcast | 50 | 42 | 0 | 7 |
| New Network | 50 | 42 | 0 | 8 |
Basic Configuration on Router 1
| Router>enable Router#configure terminal Router(config)#hostname R1 R1(config)#interface fastEthernet 0/0 R1(config-if)#ip address 50.0.0.1 255.224.0.0 R1(config-if)#no shutdown R1(config-if)#exit R1(config)#interface serial 0/0/0 R1(config-if)#ip address 50.42.0.1 255.255.255.252 R1(config-if)#clock rate 64000 R1(config-if)#no shutdown R1(config-if)#exit R1(config)#exit R1#write |
Basic Configuration on Router 2
| Router>enable Router#configure terminal Router(config)#hostname R2 R2(config)#interface fastEthernet 0/0 R2(config-if)#ip address 50.32.0.1 255.248.0.0 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#interface serial 0/1/0 R2(config-if)#ip address 50.42.0.2 255.255.255.252 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#interface serial 0/0/0 R2(config-if)#ip address 50.42.0.5 255.255.255.252 R2(config-if)#clock rate 64000 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#exit R2#write |
Basic Configuration on Router 3
| Router>enable Router#configure terminal Router(config)#hostname R3 R3(config)#interface fastEthernet 0/0 R3(config-if)#ip address 50.40.0.1 255.254.0.0 R3(config-if)#no shutdown R3(config-if)#exit R3(config)#interface serial 0/1/0 R3(config-if)#ip address 50.42.0.6 255.255.255.252 R3(config-if)#no shutdown R3(config-if)#exit R3(config)#exit R3#write |
OSPF Multi Area Configuration on Router 1
| R1>enable R1#configure terminal R1(config)#router ospf 30 R1(config-router)#network 50.0.0.1 0.0.0.0 area 1 R1(config-router)#network 50.42.0.1 0.0.0.0 area 0 R1(config-router)#exit R1(config)#exit R1#write |
OSPF Multi Area Configuration on Router 2
| R2>enable R2#configure terminal R2(config)#router ospf 30 R2(config-router)#network 50.42.0.2 0.0.0.0 area 0 R2(config-router)#network 50.32.0.1 0.0.0.0 area 0 R2(config-router)#network 50.42.0.5 0.0.0.0 area 0 R2(config-router)#exit R2(config)#exit R2#write |
OSPF Multi Area Configuration on Router 3
| R3>enable R3#configure terminal R3(config)#router ospf 30 R3(config-router)#network 50.42.0.6 0.0.0.0 area 0 R3(config-router)#network 50.40.0.1 0.0.0.0 area 2 R3(config-router)#exit R3(config)#exit R3#write |
Verification on Router 1
| R1#show ip route 50.0.0.0/8 is variably subnetted, 5 subnets, 4 masks C 50.0.0.0/11 is directly connected, FastEthernet0/0 O 50.32.0.0/13 [110/65] via 50.42.0.2, 00:01:15, Serial0/0/0 O IA 50.40.0.0/15 [110/129] via 50.42.0.2, 00:00:09, Serial0/0/0 C 50.42.0.0/30 is directly connected, Serial0/0/0 O 50.42.0.4/30 [110/128] via 50.42.0.2, 00:01:05, Serial0/0/0 |
Verification on Router 2
| R2#show ip route 50.0.0.0/8 is variably subnetted, 5 subnets, 4 masks O IA 50.0.0.0/11 [110/65] via 50.42.0.1, 00:01:36, Serial0/1/0 C 50.32.0.0/13 is directly connected, FastEthernet0/0 O IA 50.40.0.0/15 [110/65] via 50.42.0.6, 00:00:22, Serial0/0/0 C 50.42.0.0/30 is directly connected, Serial0/1/0 C 50.42.0.4/30 is directly connected, Serial0/0/0 |
Verification on Router 3
| R3#show ip route 50.0.0.0/8 is variably subnetted, 5 subnets, 4 masks O IA 50.0.0.0/11 [110/129] via 50.42.0.5, 00:01:07, Serial0/1/0 O 50.32.0.0/13 [110/65] via 50.42.0.5, 00:01:07, Serial0/1/0 C 50.40.0.0/15 is directly connected, FastEthernet0/0 O 50.42.0.0/30 [110/128] via 50.42.0.5, 00:01:07, Serial0/1/0 C 50.42.0.4/30 is directly connected, Serial0/1/0 |
