Netgear RT338 참조 가이드
Reference Guide for the Model RT338 ISDN Router
1-14
Introduction
MAC Addresses and Address Resolution Protocol
An IP address alone cannot be used to deliver data from one LAN device to another. In order for
data to be sent between LAN devices, you must convert the IP address of the destination device to
its media access control (MAC) address. Each device on an Ethernet network has a unique MAC
address, which is a 48-bit number assigned to each device by the manufacturer. The technique that
associates the IP address with a MAC address is known as address resolution. Internet protocol
uses the Address Resolution Protocol (ARP) to resolve MAC addresses.
data to be sent between LAN devices, you must convert the IP address of the destination device to
its media access control (MAC) address. Each device on an Ethernet network has a unique MAC
address, which is a 48-bit number assigned to each device by the manufacturer. The technique that
associates the IP address with a MAC address is known as address resolution. Internet protocol
uses the Address Resolution Protocol (ARP) to resolve MAC addresses.
If a device sends data to another station on the network and the destination MAC address is not yet
recorded, ARP is used. An ARP request is broadcast onto the network. All stations on the network
receive and read the request. The destination IP address for the chosen station is included as part of
the message so that only the station with this IP address responds to the ARP request. All other
stations discard the request.
recorded, ARP is used. An ARP request is broadcast onto the network. All stations on the network
receive and read the request. The destination IP address for the chosen station is included as part of
the message so that only the station with this IP address responds to the ARP request. All other
stations discard the request.
The station with the correct IP address responds with its own MAC address directly to the sending
device. The receiving station provides the transmitting station with the required destination MAC
address. The IP address data and MAC address data for each station are held in an ARP table.
The next time data is sent, the address can be obtained from the address information in the table.
device. The receiving station provides the transmitting station with the required destination MAC
address. The IP address data and MAC address data for each station are held in an ARP table.
The next time data is sent, the address can be obtained from the address information in the table.
Domain Name System Server
Many of the resources on the Internet can be addressed by simple descriptive names such as
. This addressing is very helpful at the application level, but the
descriptive name must be translated to an IP address in order for a user to actually contact the
resource. Just as a telephone directory maps names to phone numbers, or as an ARP table maps
IP addresses to MAC addresses, a domain name system (DNS) server maps descriptive names of
network resources to IP addresses.
resource. Just as a telephone directory maps names to phone numbers, or as an ARP table maps
IP addresses to MAC addresses, a domain name system (DNS) server maps descriptive names of
network resources to IP addresses.
When a PC accesses a resource by its descriptive name, it first contacts a DNS server to obtain the
IP address of the resource. The PC sends the desired message using the IP address. Many large
organizations such as ISPs maintain their own DNS servers and allow their customers to use the
servers to look up addresses.
IP address of the resource. The PC sends the desired message using the IP address. Many large
organizations such as ISPs maintain their own DNS servers and allow their customers to use the
servers to look up addresses.