Default Routing | How To Configure Default Route On Cisco

Default Routing VLSM

Given Network: 198.10.10.0

Required hosts on Router 1: 120

Required hosts on Router 2: 30

R1<= 120 hosts

120<= 2ⁿ – 2

120<= 2⁷ – 2

120<= 128 – 2

120<= 126

Total number of network bits= 32

32 – n = 32 – 7 = 25 (CIDR value of Router 1 i.e. Given network)

i.e. 198.10.10.0/25

N.S.M = 11111111. 11111111. 11111111.10000000

                        = 255.255.255.128

Block Size        = 256 – N.S.M

                        = 256 – 128 = 128

Note: Add this block size in given network so that we can get our new network for Router 2.

so the new network is 198.10.10.128/?

Now find FVH, LVH and Broadcast address

Given Network	198	10	10	0
First Valid Host-FVH	198	10	10	1
Last Valid Host-LVH	198	10	10	126
Broadcast	198	10	10	127
New Network	198	10	10	128

R2<= 30 hosts

30<= 2ⁿ – 2

30<= 2⁵ – 2

30<= 32 – 2

30<= 30

Total number of network bits = 32

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

i.e. 198.10.10.128/27

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 1 and 2 (Virtual Network).

so the new network is 198.10.10.160/?

Now find FVH, LVH and Broadcast address

Given Network	198	10	10	128
First Valid Host-FVH	198	10	10	129
Last Valid Host-LVH	198	10	10	158
Broadcast	198	10	10	159
New Network	198	10	10	160

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. 198.10.10.160/30

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. This network can be used in future.

so the new network is 198.10.10.164/?

Now find FVH, LVH and Broadcast address

Given Network	198	10	10	160
First Valid Host-FVH	198	10	10	161
Last Valid Host-LVH	198	10	10	162
Broadcast	198	10	10	163
New Network	198	10	10	164

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 195.100.0.1  255.255.255.224 R1(config-if)#no shutdown R1(config-if)#exit   R1(config)#interface serial 0/0/0 R1(config-if)#ip address 195.100.0.49 255.255.255.252 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 195.100.0.33 255.255.255.240 R2(config-if)#no shutdown R2(config-if)#exit   R2(config)#interface serial 0/1/0 R2(config-if)#ip address 195.100.0.50 255.255.255.252 R2(config-if)#no shutdown R2(config-if)#exit R2(config)#exit R2#write

Default Routing Configuration on Router 1

R1>enable R1#configure terminal R1(config)#ip route 0.0.0.0                0.0.0.0             198.10.10.162 R1(config)#exit R1#write

Default Routing Configuration on Router 2

R2>enable R2#configure terminal R2(config)#ip route 0.0.0.0                0.0.0.0             198.10.10.161 R2(config)#exit R2#write

Verification on Router 1

R1#show ip route      198.10.10.0/24 is variably subnetted, 2 subnets, 2 masks C       198.10.10.0/25 is directly connected, FastEthernet0/0 C       198.10.10.160/30 is directly connected, Serial0/0/0 S*   0.0.0.0/0 [1/0] via 198.10.10.162

Verification on Router 2

R2#show ip route      198.10.10.0/24 is variably subnetted, 2 subnets, 2 masks C       198.10.10.128/27 is directly connected, FastEthernet0/0 C       198.10.10.160/30 is directly connected, Serial0/1/0 S*   0.0.0.0/0 [1/0] via 198.10.10.161

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