Arp - Hirschmann Power MICE User Manual

Routing - Basics

2.1 ARP

The Address Resolution Protocol (ARP) determines the MAC address that
belongs to an IP address. What is the benefit of this?
Let's suppose that you want to configure your Switch using the Web-based
interface. You enter the IP address of your Switch in the address line of
your browser. But which MAC address will your PC now use to display the
information in the Switch in your browser window?
If the IP address of the Switch is in the same subnet as your PC, then your
PC sends what is known as an ARP request. This is a MAC broadcast data
packet that requests the owner of the IP address to send back his
MAC address. The Switch replies with a unicast data packet containing his
MAC address. This unicast data packet is called an ARP reply.
149.218.112.159
00:80:63:10:11:12
Reply to PC:
My MAC address is
00:80:63:10:11:25.
Figure 3: ARP request and reply
14
Query to everyone:
Whoever has the
IP address 149.218.112.101
please send me your MAC address.
149.218.112.101
00:80:63:10:11:25
2.1 ARP
Routing L3E
Release 4.2 08/08