IPC@CHIP
®
DK55
Getting Started V1.0
3.4.6 IPv4
Basics
On an IP network IP addresses are used to define the source and the destination of a data
packet. An advantage of IP addresses is that they also hold information on a device’s physical
location in a large network. This is best explained by an example:
Suppose you have the address 172.30.10.50 and the network mask 255.255.240.0. Let’s look
at this data in binary format:
IP address
172.30.10.50
10101100.00011110.00001010.00110010
Network mask
255.255.240.0
11111111.11111111.11110000.00000000
Logical AND of both
10101100.00011110.00000000.00000000
The first 20 bits of the network mask are 1. This means that the first 20 bits of the IP address
identify the network. The last 12 bits (those that are 0 in the network mask) identify the device
within this network. This means that in the given example we can give the devices in our
network the addresses 172.30.0.1 through 172.30.15.254. The lowest (here 172.30.0.0) and
the highest address (here 172.30.15.255) of a network are reserved and cannot be assigned
to a host. The lowest address identifies the network, the highest one is a broadcast address,
used for a broadcast to all devices on this section of the network. Messages sent to this
address are received by all devices.
Any address that is not within the range of the current network is passed to the gateway
address (the router). A gateway is a physical machine, hardwired into two or more physical
networks. It knows how to transfer an IP packet from one network to another.
You can find the network configuration of the network that you are connected to by entering
the command
IPCONFIG
in a Windows command shell.
On a network, no two devices are allowed to have the same address.
Copyright © 2007 Beck IPC GmbH
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