IPv4 Addresses

Chapter 5

1

2

Classful Addressing

3

Address Space

4

Netid and Hostid

5

Two-Level Addressing

netid

First address000 ... 0

6

Network Mask

7

Three-Level Addressing: Subnetting

8

Subnetting

9

Supernetting

10

Supernetting - Example

11

Classless Addressing (CIDR)

12

Example

Address: 167.199.170.82/27

First Address: 167.199.170.64/27

Last Address: 167.199.170.95/27

13

Subnetting

14.24.74.127/25 14.24.74.191/26

14.24.74.207/28

14.24.74.192/28

A block of 256 addresses (14.24.74.0/24) is divided into 3 subblocks of 120, 60, and 10 addresses.

14.24.74.00000000

14.24.74.01111111 14.24.74.10111111

14.24.74.10000000

14.24.74.11001111

14.24.74.11000000

14

Address Allocation

ISP granted a block: 190.100.0.0/16 (65,536 addresses)

❑ Group 1 has 64 customers; each needs 256 addresses❑ Group 2 has 128 customers; each needs 128 addresses❑ Group 3 has 128 customers; each needs 64 addresses

15

Address Allocation

190.100.0.0/18

190.100.64.0/18

190.100.128.0/19

16

All-Zeros Address

Source: 0.0.0.0Destination: 255.255.255.255

Packet

17

All-Ones Address: Limited Broadcast Address

221.45.71.20/24 221.45.71.178/24

221.45.71.64/24 221.45.71.126/24Network

Destination IP address:255.255.255.255Packet

Router blocks �the packet

18

Direct Broadcast Address

221.45.71.0/24

221.45.71.20/24 221.45.71.178/24

221.45.71.64/24 221.45.71.126/24Network:

Packet

Destination IP address:221.45.71.255

SpecificPrefix Suffix

All 1s

19

Loopback Addresses

Transport layer

Application layer

Network layer

Process 1 Process 2

Destination address:127.x.y.z

Packet

20

Private Addresses