ZyXEL Communications wireless n gigbit router zyxel manual 155

Chapter 9 LAN

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 NBG-460N) 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 NBG-460N.

1When 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 NBG-460N) by looking at the MAC address in its ARP table.

2When the computer cannot locate the default gateway, an ARP request is broadcast on the LAN.

3The NBG-460N receives the ARP request and replies to the computer with its own MAC address.

4The 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 NBG-460N.

5When the NBG-460N 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 NBG- 460N and the Internet as if it is in the same subnet as the NBG-460N.

NBG-460N User’s Guide

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