Networking Test Friday Online

© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 1

Subnetting

Network Fundamentals – Chapter 6

Dr. C. BouSaba

2© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Prefix /24

Three octets in network part, last octet in host part.

All possible numbers 0 – 255 in last octet belong in the same network.

Network address yellow Broadcast address blue

Subnet mask 255.255.255.0

3© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Prefix /25

First bit of fourth octet taken into network part.

For every bit taken, double number of networks, halve their size.

Network address yellow Broadcast address blue

Subnet mask 255.255.255.128

4© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Prefix /26

2 bits of fourth octet taken into network part.

For every bit taken, double number of networks, halve their size.

Network address yellow Broadcast address blue

Subnet mask 255.255.255.192

5© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Prefix /27

3 bits of fourth octet taken into network part.

For every bit taken, double number of networks, halve their size.

Network address yellow Broadcast address blue

Subnet mask 255.255.255.224

6© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Prefix /28

4 bits of fourth octet taken into network part.

For every bit taken, double number of networks, halve their size.

Network address yellow Broadcast address blue

Subnet mask 255.255.255.240

7© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Prefix /29

5 bits of fourth octet taken into network part.

For every bit taken, double number of networks, halve their size.

Network address yellow Broadcast address blue

Subnet mask 255.255.255.248

8© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Prefix /30

6 bits of fourth octet taken into network part.

For every bit taken, double number of networks, halve their size.

Network address yellow Broadcast address blue

Subnet mask 255.255.255.252

9© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Variable length

Networks do not need to be all the same size.

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10© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public