In this lab, I will show you Default – Combination of Class C and Class A on 3 Routers
Table of Contents
VLSM
Given Network: 220.0.0.0
Required host on Router 1= 40,00,000
Required host on Router 2= 10,00,000
Required host on Router 3= 5,00,000
R1<=40,00,000
40,00,000<=2n – 2
40,00,000 <=222 – 2
40,00,000<=41,94,304 – 2
40,00,000<=41,94,302
Total number of network bits = 32
32 – n = 32 – 22 = 10 (CIDR value of Router 1 i.e. Given network)
i.e. 220.0.0.0/10
N.S.M = 11111111.11000000.00000000.00000000
= 255.192.0.0
Block Size = 256 – N.S.M
= 256 – 192 = 64
Note: Add this block size in given network so that we can get our new network for Router 2.
so the new network is 220.64.0.0/?
Now find FVH, LVH and Broadcast address
| Given Network | 220 | 0 | 0 | 0 |
| First Valid Host-FVH | 220 | 0 | 0 | 1 |
| Last Valid Host-LVH | 220 | 63 | 255 | 254 |
| Broadcast | 220 | 63 | 255 | 255 |
| New Network | 220 | 64 | 0 | 0 |
R2<=10,00,000
10,00,000<=2n – 2
10,00,000<=220 – 2
10,00,000<=10,48,576 – 2
10,00,000<=10,48,574
Total number of network bits = 32
32 – n = 32 – 20 = 12 (CIDR value of Router 2 i.e. New network)
i.e. 220.64.0.0/12
N.S.M = 11111111.11110000.00000000.00000000
= 255.240.0.0
Block Size = 256 – N.S.M
= 256 – 240 = 16
Note: Add this block size in given network so that we can get our new network for Router 3.
so the new network is 220.80.0.0/?
Now find FVH, LVH and Broadcast address
| Given Network | 220 | 64 | 0 | 0 |
| First Valid Host-FVH | 220 | 64 | 0 | 1 |
| Last Valid Host-LVH | 220 | 79 | 255 | 254 |
| Broadcast | 220 | 79 | 255 | 255 |
| New Network | 220 | 80 | 0 | 0 |
R3<=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. 220.80.0.0/13
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 1 and Router 2 (Virtual Network).
so the new network is 220.88.0.0/?
Now find FVH, LVH and Broadcast address
| Given Network | 220 | 80 | 0 | 0 |
| First Valid Host-FVH | 220 | 80 | 0 | 1 |
| Last Valid Host-LVH | 220 | 88 | 255 | 254 |
| Broadcast | 220 | 88 | 255 | 255 |
| New Network | 220 | 88 | 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. 220.88.0.0/30
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 220.88.0.4/30?
Now find FVH, LVH and Broadcast address
| Given Network | 220 | 88 | 0 | 0 |
| First Valid Host-FVH | 220 | 88 | 0 | 1 |
| Last Valid Host-LVH | 220 | 88 | 0 | 2 |
| Broadcast | 220 | 88 | 0 | 3 |
| New Network | 220 | 88 | 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. 220.88.0.4/30
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 220.88.0.8/?
Now find FVH, LVH and Broadcast address
| Given Network | 220 | 88 | 0 | 4 |
| First Valid Host-FVH | 220 | 88 | 0 | 5 |
| Last Valid Host-LVH | 220 | 88 | 0 | 6 |
| Broadcast | 220 | 88 | 0 | 7 |
| New Network | 220 | 88 | 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 220.0.0.1 255.192.0.0 R1(config-if)#no shutdown R1(config-if)#exit R1(config)#interface serial 0/0/0 R1(config-if)#ip address 220.88.0.1 255.255.255.252 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 220.64.0.1 255.240.0.0 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#interface serial 0/1/0 R2(config-if)#ip address 220.88.0.2 255.255.255.252 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#interface serial 0/0/0 R2(config-if)#ip address 220.88.0.5 255.255.255.252 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 220.80.0.1 255.248.0.0 R3(config-if)#no shutdown R3(config-if)#exit R3(config)#interface serial 0/1/0 R3(config-if)#ip address 220.88.0.6 255.255.255.252 R3(config-if)#no shutdown R3(config-if)#exit R3(config)#exit R3#write |
Default Configuration on Router 1
| R1>enable R1#configure terminal R1(config)#ip route 0.0.0.0 0.0.0.0 220.88.0.2 R1(config)#exit R1#write |
Static Configuration on Router 2
| R2>enable R2#configure terminal R2(config)#ip route 220.0.0.0 255.192.0.0 220.88.0.1 R2(config)#ip route 220.80.0.0 255.248.0.0 220.88.0.6 R2(config)# R2(config)#ip route 220.88.0.0 255.255.255.252 220.88.0.1 R2(config)#ip route 220.88.0.4 255.255.255.252 220.88.0.6 R2(config)#exit R2#write |
Default Configuration on Router 3
| R3>enable R3#configure terminal R3(config)#ip route 0.0.0.0 0.0.0.0 220.88.0.5 R3(config)#exit R3#write |
Verification on Router 1
| R1#show ip route C 220.0.0.0/10 is directly connected, FastEthernet0/0 220.88.0.0/30 is subnetted, 1 subnets C 220.88.0.0 is directly connected, Serial0/0/0 S* 0.0.0.0/0 [1/0] via 220.88.0.2 |
Verification on Router 2
| R2#show ip route S 220.0.0.0/10 [1/0] via 220.88.0.1 C 220.64.0.0/12 is directly connected, FastEthernet0/0 S 220.80.0.0/13 [1/0] via 220.88.0.6 220.88.0.0/30 is subnetted, 2 subnets C 220.88.0.0 is directly connected, Serial0/1/0 C 220.88.0.4 is directly connected, Serial0/0/0 |
Verification on Router 3
| R3#show ip route C 220.80.0.0/13 is directly connected, FastEthernet0/0 220.88.0.0/30 is subnetted, 1 subnets C 220.88.0.4 is directly connected, Serial0/1/0 S* 0.0.0.0/0 [1/0] via 220.88.0.5 |
