CCNA part 3 subnetting
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This document discusses subnetting and its advantages such as reducing network traffic and optimizing performance. It provides formulas for calculating the number of subnets and hosts using the number of network and host bits. Examples are given for subnetting a Class C network with 60 hosts into 4 subnets using a /26 netmask. The document also covers VLSM, which allows further subnetting of existing subnets. Finally, it discusses CIDR notation which is used by ISPs to allocate IP address blocks to customers based on their subnet mask CIDR value.
CCNA part 3 subnetting
- 1. SUBNETTING
- 2. Advantages of Subnetting:- • Reduce network Traffic. • Optimized network performance. • Simplified management. • Facilitated spanning of large geographical distance. • Bandwidth utilization will increase.
- 3. Formula For Subnetting:- • 2^h – 2 >= No. of host per network. Where h:- no host Bits • 2^n – 2 >= No. of sub networks. Where n:- no network Bits
- 4. Examples of Class C:- • Required hosts are:-40 • 2^h – 2 >= 40 hosts. • 2^6 – 2 >= 40 hosts hence h=6 & n= 2 • No of Subnetworks 2^2 – 2=2subnetworks. • Subnetworks are:- • 192.168.1.0 – 192.168.1.63 192.168.1.64 – 192.168.1.127 192.168.1.128 – 192.168.1.191 192.168.1.192 – 192.168.1.255 Subnetmask= 255.255.255.192
- 5. Examples of Class C:- • Required hosts=2 • Bits h=2 and n=6. • No of subnetworks = 64-2=62 • Subnetmask= 255.255.255.252 • Range of network=4
- 6. Examples of Class C:- • Ex. 192.168.1.0/28 Network Bits n=4 and host Bits =4. • No. of Subnets=14 • No 0f host/Net =14 • Subnetmask =255.255.255.240 • Range of network is =16
- 7. Examples of Class C:- • Ex. 192.168.1.0/29 Network Bits n=5 and host Bits =3. • No. of Subnets=30 • No 0f host/Net =6 • Subnetmask =255.255.255.248 • Range of network is =8
- 8. Examples of Class B:- • Ex. 172.16.0.0/18 Network Bits n=2 and host Bits =14. • No. of Subnets=2 • No 0f host/Net =16382 • Subnetmask =255.255.192.0.0 • Range of network is:- 172.16.0.0 ------- 172.16.63.255 172.16.64.0 ------- 172.16.127.255 172.16.128.0 ------- 172.16.191.255 172.16.192.0 ------- 172.16.255.255
- 9. VLSM • Variable length subnet mask. • Subnetting of Subnets. • Formula:- 2^h – 2 >= No. of host per network. Where h:- no host Bits 2^n >= No. of sub networks. Where n:- no network Bits
- 10. Example of VLSM:- Subnetting:- (class C) • E.g.:-192.168.1.0 • Required hosts are:-60 • I.e. h=6 & n= 2 • Subnetworks are:- 192.168.1.0 – 192.168.1.63 192.168.1.64 – 192.168.1.127 192.168.1.128 – 192.168.1.191 192.168.1.192 – 192.168.1.255 Subnetmask= 255.255.255.192 VLSM:- • E.g. 192.168.1.64 (255.255.255.192) • Required host are:-14. • Now n+h=6 • 2^h – 2 = no of host per subnet. I.e. h=4and n= 2 • 2^ n = no subnet I.e. 4 subnetworks • Subnetworks are:- 192.168.1.64 – 192.168.1.79 192.168.1.80 – 192.168.1.95 192.168.1.96 – 192.168.1.111 192.168.1.112 – 192.168.127. • New subnetmask= 255.255.255.240
- 11. CIDR • Classless inter-domain routing. • It’s basically the method that ISPs use to allocate an amount of address to a company (home – customer). • CIDR Values:- subnet mask CIDR value 255.0.0.0 /8 255.128.0.0 /9 255.192.0.0 /10 255.255.255.252 /30