ZyXEL N4100 Guia Do Utilizador

 Chapter 4 System Setup

N4100 User’s Guide

Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol 
address (IP address) to a physical machine address, also known as a Media Access 
Control or MAC address, on the local area network. IP routing table is defined on 
IP Ethernet devices (the N4100) to decide which hop to use,

 

to help forward data 

along to its specified destination.

The following lists out the steps taken, when a computer tries to access the 
Internet for the first time through the N4100.

When a computer (which is in a different subnet) first attempts to access the 
Internet, it sends packets to its default gateway (which is not the N4100) by 
looking at the MAC address in its ARP table. 

When the computer cannot locate the default gateway, an ARP request is 
broadcast on the LAN. 

The N4100 receives the ARP request and replies to the computer with its own MAC 
address. 

The computer updates the MAC address for the default gateway to the ARP table. 
Once the ARP table is updated, the computer is able to access the Internet 
through the N4100. 

When the N4100 receives packets from the computer, it creates an entry in the IP 
routing table so it can properly forward packets intended for the computer. 

After all the routing information is updated, the computer can access the N4100 
and the Internet as if it is in the same subnet as the N4100.