In this lab, I am gonna teach you Basic Configuration of 4 Routers

VLSM

Given Network: 210.80.50.0

Required hosts on Router 1= 50

Required hosts on Router 2= 25

Required hosts on Router 3= 14

Required hosts on Router 4= 5

R1<= 50

50<= 2ⁿ – 2

50<= 2⁶ – 2

50<= 64 – 2

50<= 62

Total number of network bits = 32

32 – n = 32 – 6 = 26 (CIDR value of given network i.e. Router 1)

i.e. 210.80.50.0/26

N.S.M = 11111111. 11111111. 11111111.11000000

                        = 255.255.255.192

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 210.80.50.64/?

Now find FVH, LVH and Broadcast address

Given Network	210	80	50	0
First Valid Host-FVH	210	80	50	1
Last Valid Host-LVH	210	80	50	62
Broadcast	210	80	50	63
New Network	210	80	50	64

R2<= 25

25<= 2ⁿ – 2

25<= 2⁵ – 2

25<= 32 – 2

25<= 30

Total number of network bits = 32

32 – n = 32 – 5 = 27 (CIDR value of given network i.e. Router 2)

i.e. 210.80.50.64/27

N.S.M = 11111111. 11111111. 11111111.11100000

                        = 255.255.255.224

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 3.

So the new network is 210.80.50.96/?

Now find FVH, LVH and Broadcast address

Given Network	210	80	50	64
First Valid Host-FVH	210	80	50	65
Last Valid Host-LVH	210	80	50	94
Broadcast	210	80	50	95
New Network	210	80	50	96

R3<= 14

14<= 2ⁿ – 2

14<= 2⁴ – 2

14<= 16 – 2

14<= 14

Total number of network bits = 32

32 – n = 32 – 4 = 28 (CIDR value of given network i.e. Router 3)

i.e. 210.80.50.96/28

N.S.M = 11111111. 11111111. 11111111.11110000

                        = 255.255.255.240

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 4.

So the new network is 210.80.50.112/?

Now find FVH, LVH and Broadcast address

Given Network	210	80	50	96
First Valid Host-FVH	210	80	50	97
Last Valid Host-LVH	210	80	50	110
Broadcast	210	80	50	111
New Network	210	80	50	112

R4 <= 5

5 <= 2ⁿ – 2

5 <= 2³ – 2

5 <= 8 – 2

5 <= 6

Total number of network bits = 32

32 – n = 32 – 3 = 29 (CIDR of given network i.e. Router 4)

i.e. 210.80.50.112/29

N.S.M = 11111111.11111111.11111111.11111000

= 255.255.255.248

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 2 (Virtual Network).

so the new network is 210.80.50.120/?

Now find FVH, LVH and Broadcast address

Given Network	210	80	50	112
First Valid Host-FVH	210	80	50	113
Last Valid Host-LVH	210	80	50	118
Broadcast	210	80	50	119
New Network	210	80	50	120

Router 1 & 2 <= 2 hosts (we required only two IP to connect 2 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. 210.80.50.120/30

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 3 (Virtual Network).

so the new network is 210.80.50.124/?

Now find FVH, LVH and Broadcast address

Given Network	210	80	50	120
First Valid Host-FVH	210	80	50	121
Last Valid Host-LVH	210	80	50	122
Broadcast	210	80	50	123
New Network	210	80	50	124

Router 2 & 3 <= 2 hosts (we required only two IP to connect 2 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. 210.80.50.124/30

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 3 and 4 (Virtual Network).

so the new network is 210.80.50.128/?

Now find FVH, LVH and Broadcast address

Given Network	210	80	50	124
First Valid Host-FVH	210	80	50	125
Last Valid Host-LVH	210	80	50	126
Broadcast	210	80	50	127
New Network	210	80	50	128

Router 3 & 4 <= 2 hosts (we required only two IP to connect 2 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 (R3&R4)

i.e. 210.80.50.128/30

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 5. This network can be used in future.

so the new network is 210.80.50.132/?

Now find FVH, LVH and Broadcast address

Given Network	210	80	50	128
First Valid Host-FVH	210	80	50	129
Last Valid Host-LVH	210	80	50	130
Broadcast	210	80	50	131
New Network	210	80	50	132

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 210.80.50.1 255.255.255.192 R1(config-if)#no shutdown R1(config-if)#exit   R1(config)#interface serial 0/0/0 R1(config-if)#ip address 210.80.50.121 255.255.255.252 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 210.80.50.65 255.255.255.224 R2(config-if)#no shutdown R2(config-if)#exit   R2(config)#interface serial 0/1/0 R2(config-if)#ip address 210.80.50.122 255.255.255.252 R2(config-if)#no shutdown R2(config-if)#exit   R2(config)#interface serial 0/0/0 R2(config-if)#ip address 210.80.50.125 255.255.255.252 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 210.80.50.93 255.255.255.240 R3(config-if)#no shutdown R3(config-if)#exit   R3(config)#interface serial 0/1/0 R3(config-if)#ip address 210.80.50.126 255.255.255.252 R3(config-if)#no shutdown R3(config-if)#exit   R3(config)#interface serial 0/0/0 R3(config-if)#ip address 210.80.50.129 255.255.255.252 R3(config-if)#clock rate 64000 R3(config-if)#no shutdown R3(config-if)#exit R3(config)#exit R3#write

Basic Configuration on Router 4

Router>enable Router#configure terminal Router(config)#hostname R4 R4(config)#interface fastEthernet 0/0 R4(config-if)#ip address 210.80.50.109 255.255.255.248 R4(config-if)#no shutdown R4(config-if)#exit   R4(config)#interface serial 0/1/0 R4(config-if)#ip address 210.80.50.130 255.255.255.252 R4(config-if)#no shutdown R4(config-if)#exit R4(config)#exit R4#write

Verification on Router 1

R1#show ip route      210.80.50.0/24 is variably subnetted, 2 subnets, 2 masks C       210.80.50.0/26 is directly connected, FastEthernet0/0 C       210.80.50.120/30 is directly connected, Serial0/0/0

Verification on Router 2

R2#show ip route      210.80.50.0/24 is variably subnetted, 3 subnets, 2 masks C       210.80.50.64/27 is directly connected, FastEthernet0/0 C       210.80.50.120/30 is directly connected, Serial0/1/0 C       210.80.50.124/30 is directly connected, Serial0/0/0

Verification on Router 3

R3#show ip route      210.80.50.0/24 is variably subnetted, 3 subnets, 2 masks C       210.80.50.96/28 is directly connected, FastEthernet0/0 C       210.80.50.124/30 is directly connected, Serial0/1/0 C       210.80.50.128/30 is directly connected, Serial0/0/0

Verification on Router 4

R4#show ip route      210.80.50.0/24 is variably subnetted, 2 subnets, 2 masks C       210.80.50.112/29 is directly connected, FastEthernet0/0 C       210.80.50.128/30 is directly connected, Serial0/1/0

If you like our LABs, you can support us by donating just $1. It will really encourage us. EIHeducation