User Manual for the NETGEAR WGE111 Wireless Game Adapter

Understanding IP Addresses

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Address Resolution Protocol

An IP address alone cannot be used to deliver data from one device to another on a LAN. In order

for data to be sent from one device on the LAN to another, 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 Ethernet 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, and IP uses the Address Resolution Protocol (ARP) to do this.

If a device needs to send data to another station on the network and it does not already have the

destination MAC address recorded, ARP is used. An ARP request is broadcast onto the network,

and all stations receive and read the request. The destination IP address is included as part of the

message so that only the station with the correct IP address responds to the ARP request and all

other nodes discard it.

The node with the right IP address responds with its own MAC address directly to the sender,

providing the transmitting station with the destination MAC address needed for it to send the data.

The IP address data and MAC address data for each node are held in an ARP table, so that the next

time data needs to be sent, the address can be obtained from the address information in the table.

IP Configuration by DHCP

When an IP-based local area network is installed, each workstation must be configured with an IP

address. If the workstations need to access the Internet, they should also be configured with a

gateway address and one or more DNS server addresses. As an alternative to manual

configuration, there is a method by which each device on the network can obtain this configuration

information automatically. A device on the network may act as a Dynamic Host Configuration

Protocol (DHCP) server. The DHCP server stores a list or pool of IP addresses, along with other

information (such as gateway and DNS addresses) that it may assign to the other devices on the

network. The most of NETGEAR routers have the capacity to act as a DHCP server.

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Understanding IP Addresses

Wireless Networking Basics

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Appendix C

Wireless Networking Basics

This chapter provides an overview of wireless networking.

Wireless Networking Overview

On an 802.11b or g wireless link, data is encoded using direct-sequence spread-spectrum (DSSS)

technology and is transmitted in the unlicensed radio spectrum at 2.5GHz. The maximum data rate

for the wireless link is 11 Mbps, but it will automatically back down from 11 Mbps to 5.5, 2, and 1

Mbps when the radio signal is weak or when interference is detected. The 802.11g auto rate

sensing rates are 1, 2, 5.5, 6, 9, 12, 18, 24, 36, 48, and 54 Mbps.

The 802.11 standard is also called Wireless Ethernet or Wi-Fi by the Wireless Ethernet

Compatibility Alliance (WECA, see

), an industry standard group promoting

interoperability among 802.11 devices. The 802.11 standard offers two methods for configuring a

wireless network — ad hoc and infrastructure.

Infrastructure Mode

With a wireless access point, you can operate the wireless LAN in the infrastructure mode. This

mode provides wireless connectivity to multiple wireless network devices within a fixed range or

area of coverage, interacting with wireless nodes via an antenna.

In the infrastructure mode, the wireless access point converts airwave data into wired Ethernet

data, acting as a bridge between the wired LAN and wireless clients. Connecting multiple access

points via a wired Ethernet backbone can further extend the wireless network coverage. As a

mobile computing device moves out of the range of one access point, it moves into the range of

another. As a result, wireless clients can freely roam from one access point domain to another and

still maintain seamless network connection.

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Wireless Networking Basics

Ad Hoc Mode (Peer-to-Peer Workgroup)

In an ad hoc network, computers are brought together as needed; thus, there is no structure or fixed

points to the network — each node can generally communicate with any other node. There is no

access point involved in this configuration. This mode enables you to quickly set up a small

wireless workgroup and allows workgroup members to exchange data or share printers as

supported by Microsoft networking in the various Windows operating systems. Some vendors also

refer to ad hoc networking as peer-to-peer group networking.

In this configuration, network packets are directly sent and received by the intended transmitting

and receiving stations. As long as the stations are within range of one another, this is the easiest

and least expensive way to set up a wireless network.

Network Name: Extended Service Set Identification (ESSID)

The Extended Service Set Identification (ESSID) is one of two types of Service Set Identification

(SSID). In an ad hoc wireless network with no access points, the Basic Service Set Identification

(BSSID) is used. In an infrastructure wireless network that includes an access point, the ESSID is

used, but may still be referred to as SSID.

An SSID is a thirty-two character (maximum) alphanumeric key identifying the name of the

wireless local area network. Some vendors refer to the SSID as network name. For the wireless

devices in a network to communicate with each other, all devices must be configured with the

same SSID.

Authentication and WEP

The absence of a physical connection between nodes makes the wireless links vulnerable to

eavesdropping and information theft. To provide a certain level of security, the IEEE 802.11

standard has defined two types of authentication methods, Open System and Shared Key. With

Open System authentication, a wireless PC can join any network and receive any messages that are

not encrypted. With Shared Key authentication, only those PCs that possess the correct

authentication key can join the network. By default, IEEE 802.11 wireless devices operate in an

Open System network.

Wired Equivalent Privacy (WEP) data encryption is used when the wireless devices are configured

to operate in Shared Key authentication mode. There are two shared key methods implemented in

most commercially available products, 64-bit and 128-bit WEP data encryption.

User Manual for the NETGEAR WGE111 Wireless Game Adapter

Wireless Networking Basics

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802.11 Authentication

The 802.11 standard defines several services that govern how two 802.11 devices communicate.

The following events must occur before an 802.11 Station can communicate with an Ethernet

network through an access point such as the one built in to the WGE111:

1.

Turn on the wireless station.

2.

The station listens for messages from any access points that are in range.

3.

The station finds a message from an access point that has a matching SSID.

4.

The station sends an authentication request to the access point.

5.

The access point authenticates the station.

6.

The station sends an association request to the access point.

7.

The access point associates with the station.

8.

The station can now communicate with the Ethernet network through the access point.

An access point must authenticate a station before the station can associate with the access point or

communicate with the network. The IEEE 802.11 standard defines two types of authentication:

Open System and Shared Key.

•

Open System Authentication

allows any device to join the network, assuming that the device

SSID matches the access point SSID. Alternatively, the device can use the “ANY” SSID

option to associate with any available access point within range, regardless of its SSID.

•

Shared Key Authentication

requires that the station and the access point have the same WEP

Key to authenticate. These two authentication procedures are described below.

Open System Authentication

The following steps occur when two devices use Open System Authentication:

1.

The station sends an authentication request to the access point.

2.

The access point authenticates the station.

3.

The station associates with the access point and joins the network.

This process is illustrated below.