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ZyXEL Communications ZyAIR G-220 2.4RTS/CTS Threshold, RTS/CTS Threshold, RTS/CTS Threshold, RTS/CTS Threshold, RTS/CTS Threshold, RTS/CTS Threshold, RTS/CTS Threshold, Fragmentation Threshold

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ZyAIR G-220 User’s Guide

A large Fragmentation Threshold is recommended for networks not prone to interference while you should set a smaller threshold for busy networks or networks that are prone to interference.

If the Fragmentation Threshold value is smaller than the RTS/CTS Threshold value (see previously) you set then the RTS (Request To Send)/CTS (Clear to Send) handshake will never occur as data frames will be fragmented before they reach RTS/CTS Threshold size.

2.4RTS/CTS Threshold

A hidden node occurs when two stations are within range of the same access point, but are not within range of each other. The following figure illustrates a hidden node. Both stations are within range of the access point (AP) or wireless gateway, but out-of-range of each other, so they cannot “hear” each other, that is they do not know if the channel is currently being used. Therefore, they are considered hidden from each other.

Figure 2-6 RTS Threshold

When station A sends data to the AP, it might not know that the station B is already using the channel. If these two stations send data at the same time, collisions may occur when both sets of data arrive at the AP at the same time, resulting in a loss of messages for both stations.

RTS/CTS Threshold is designed to prevent collisions due to hidden nodes. An RTS/CTS Threshold defines the biggest size data frame you can send before an RTS (Request To Send)/CTS (Clear to Send) handshake is invoked.

When a data frame exceeds the RTS/CTS Threshold value you set (between 0 to 2432 bytes), the station that wants to transmit this frame must first send an RTS (Request To Send) message to the AP for permission to send it. The AP then responds with a CTS (Clear to Send) message to all other stations within its range to notify them to defer their transmission. It also reserves and confirms with the requesting station the time frame for the requested transmission.

Stations can send frames smaller than the specified RTS/CTS Threshold directly to the AP without the RTS (Request To Send)/CTS (Clear to Send) handshake.

Wireless Station Mode Configuration

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Contents

Page Copyright ZyXEL Limited Warranty Information for Canadian Users Federal Communications Commission (FCC) Interference Statement1 Page Customer Support Page Table of Contents Appendix A Setting up Your Computer’s IP Address Appendix B Access Point Mode Setup Example List of Figures List of Tables Table Table 3-4Station Mode: Advanced Setting… Table 5-1Information… Troubleshooting Starting ZyAIR Utility Program Preface Graphics Icons Key Getting Started This chapter introduces the ZyAIR and prepares you to use the ZyAIR Utility 1.1About Your ZyAIR 1.2ZyAIR Hardware and Utility Installation 1.3Disable Windows XP Wireless LAN Configuration Tool Step Figure 1-1Windows XP: System Tray Icon Network Connections Figure 1-2Windows XP: Wireless Network Connection Status Properties Page 1.4Accessing the ZyAIR Utility 1.5ZyAIR Modes 1.5.1 Change ZyAIR Modes Page Wireless LAN Network This chapter provides background information on wireless LAN network 2.1Overview 2.1.1SSID 2.1.2 Channel Ad-Hoc(IBSS) Figure 2-1IBSS Example Figure 2-2BSS Example 2.1.5 Roaming 2.2Wireless LAN Security 2.2.1 Data Encryption with WEP 2.3Fragmentation Threshold 2.4RTS/CTS Threshold 2.5Authentication Type 2.6Preamble Type Wireless Station Mode Configuration This chapter shows you how to configure your ZyAIR in wireless station mode 3.1Introduction 3.2The ZyAIR Utility Screen Table 3-1Station Mode: ZyAIR G-220Utility 3.2.1 Connecting to a Network 3.3The More Setting… Screen Figure 3-3Station Mode: More Setting… Table 3-2Station Mode: More Setting… Page 3.4The WEP Key Setting… Screen You must configure all four WEP keys the first time you use the ZyAIR The values for the WEP keys must be set up exactly the same on all wireless devices in the same wireless LAN ASCII WEP keys are case sensitive 3.5The Advanced Setting… Screen Page Page Access Point Mode Configuration This chapter shows you how to configure your ZyAIR in access point mode 4.1Introduction 4.1.1 Additional Setup Requirements 4.2The ZyAIR Utility Screen Figure 4-1Access Point Mode: ZyAIR G-220Utility Table 4-1Access Point Mode: ZyAIR G-220Utility 4.3The Access Point Setting Screen Figure 4-2Access Point Mode: Access Point Setting Table 4-2Access Point Mode: Access Point Setting Page 4.4The WEP Key Setting… Screen 4.5The MAC Address Filter Screen Figure 4-4Access Point Mode: MAC Filter Table 4-3Access Point Mode: MAC Filter Page Maintenance This chapter describes how to uninstall or upgrade the ZyAIR Utility 5.1The Information… Screen 5.2Unistallating the ZyAIR Utility 5.3Upgrading the ZyAIR Utility Troubleshooting 6.1Problems Starting the ZyAIR Utility Program 6.2Problem with the Link Status 6.3Problems Communicating With Other Computers Appendix A Setting up Your Computer’s IP Address If you need TCP/IP: If you need Client for Microsoft Networks: Page Verifying Your Computer’s IP Address Windows 2000/NT/XP Page Page Page Macintosh OS 8/9 Page Check your TCP/IP properties in the TCP/IP Control Panel window Macintosh OS Check your TCP/IP properties in the Network window Page Appendix B Access Point Mode Setup Example Diagram 2 Windows 2000: Network and Dial-upConnections Sharing Enable Internet Connection Sharing for this connection Diagram 3 Windows 2000: Network Properties Diagram 4 Windows 2000: Local Network Configuring the Wireless Station Computer Page Appendix C Index MAC filter type Network Type Ad-Hoc(IBSS) Online Registration Open authentication mode