1. © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ITE PC v4.0 Chapter 1 1 subnetting

2. ITE PC v4.0 Chapter 1 2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP Address Classes IP addresses are divided into classes to define the large, medium, and small networks. Class A addresses are assigned to larger networks. Class B addresses are used for medium-sized networks, Class C for small networks, Class D for Multicasting Class E for Experimental purposes

3. ITE PC v4.0 Chapter 1 3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Identifying Address Classes (0, 127 reserved)

4. ITE PC v4.0 Chapter 1 4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP address types IP address could be one of three categories Network address Host address Broadcast address

5. ITE PC v4.0 Chapter 1 5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network / Broadcast Addresses - Network address : the first IP address in it which all host part bits = 0 - Broadcast address: the last IP address in the network which all host part bits = 1 no. of host bits - other addresses are host addresses = 2 - 2 -Here are some examples: ClassNetwork AddressBroadcast Address A12.0.0.012.255.255.255 B172.16.0.0172.16.255.255 C192.168.1.0192.168.1.255

6. ITE PC v4.0 Chapter 1 6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Subnet Mask - 32 bit mask ( 1’s followed by 0’s ) - Used by routers and hosts to determine the number of network- significant bits ( identified by 1’s ) and host- significant bits in an IP address (identified by 0’s) - example : ClassNetwork Address Default subnet mask A12.0.0.0 255.0.0.0 or /8 B172.16.0.0 255.255.0.0 or /16 C192.168.0.0 255.255.255.0 or /24

7. ITE PC v4.0 Chapter 1 7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Octet Values of a Subnet Mask Subnet masks like IP addresses can be represented in the dotted decimal format like 255.255.255.0.

8. ITE PC v4.0 Chapter 1 8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Subnetting - Subnetting a network means to use the subnet mask to divide the network and break a large network up into smaller, more efficient and manageable segments, or subnets. - Subnetting is done by taking part of host bits then add it to the network part Network partHost part Subnet bits Network partHost part IP address

9. ITE PC v4.0 Chapter 1 9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Subnetting Example Divide network 192.168.1.0/24 into 4 subnets Solution: 4 subnets need 2 bits 192.168.1. 0 192.168.1. 0000 0000 to 0011 1111 192.168.1. 0100 0000 to 0111 1111 192.168.1. 1000 0000 to 1011 1111 192.168.1. 1100 0000 to 1111 1111 subnet mask is 255.255.255.192 or /26 The first subnet is 192.168.1.0/26 The second subnet is 192.168.1.64/26 The third subnet is 192.168.1.128/26 The fourth subnet is 192.168.1.192/26 0 - 63 64 - 127 128 - 191 192 - 255

10. ITE PC v4.0 Chapter 1 10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Divide network 192.168.1.0/24 into 4 subnets - Solution : 4 subnets need 2 bits - subnet mask = 255.255.255.192 - interesting octet is 192 - hop count = 256 – 192 = 64 - The first subnet is 192.168.1.0/26 - The second subnet is 192.168.1.64/26 - The third subnet is 192.168.1.128/26 - The fourth subnet is 192.168.1.192/26 Subnetting Example 0 - 63 64 - 127 128 - 191 192 - 255

11. ITE PC v4.0 Chapter 1 11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Divide network 172.168.0.0/16 into 8subnets Solution : - 8 subnets need 3 bits - subnet mask = 255.255.224.0 - interesting octet is 224 - hop count = 256 – 224 = 32 - The first subnet is 172.16.0.0/19 - The second subnet is 172.16.32.0/19 - The third subnet is 172.16.64.0/19 -The 8 th subnet is 172.16.224.0/19 Subnetting Example 172.16.0.1-172.16.31.254 172.16.32.1 -172.16.63.254 172.16.64.1-172.16.127.254 172.16.224.1-172.16.255.254

12. ITE PC v4.0 Chapter 1 12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Divide network 10.0.0.0/10 into 4subnets Solution : - 4subnets need 2 bits - subnet mask = 255.240.0. 0 - interesting octet is 240 - hop count = 256 – 240= 16 - The first subnet is 10.0.0.0/12 - The second subnet is 10.16.0.0/12 - The third subnet is 10.32.0.0/12 - The fourth subnet is 10.48.0.0/12 Subnetting Example 10.0.0.1-10.15.255.254 10.16.0.1-10.31.255.254 10.32.0.1-10.47.255.254 10.48.0.1-172.65.255.254

13. ITE PC v4.0 Chapter 1 13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Step method this method is used only when the subnet portion does NOT exceed a single octet (ex. 172.16.0.0 need 6-bits to address hosts Subnet portion is 10-bits long spanned through two bytes and this rule is NOT followed.

14. ITE PC v4.0 Chapter 1 14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public How Many Hosts in the Network  Design an address scheme for an internetwork and assign ranges for hosts, network devices and the router interface

15. ITE PC v4.0 Chapter 1 15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public How Many Networks

16. ITE PC v4.0 Chapter 1 16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses: Case 1

17. ITE PC v4.0 Chapter 1 17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses: Case 2

18. ITE PC v4.0 Chapter 1 18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses: Case 2

19. ITE PC v4.0 Chapter 1 19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Calculating Addresses: Case 2  Calculate the address ranges for sub networks

20. ITE PC v4.0 Chapter 1 20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public VLSM exercise