Manuals / Brands / Computer Equipment / Network Card / ZyXEL Communications / Computer Equipment / Network Card

ZyXEL Communications B-420 Antenna Selection and Positioning Recommendation, Antenna Characteristics, Frequency, Radiation Pattern, Antenna Gain, Types of Antennas For WLAN

1 150

Download 150 pages, 4.41 Mb

ZyAIR B-420 Wireless LAN Ethernet Adapter and Bridge

Appendix E

Antenna Selection and Positioning Recommendation

An antenna couples RF signals onto air. A transmitter within a wireless device sends an RF signal to the antenna, which propagates the signal through the air. The antenna also operates in reverse by capturing RF signals from the air.

Choosing the right antennas and positioning them properly increases the range and coverage area of a wireless LAN.

Antenna Characteristics

Frequency

An antenna in the frequency of 2.4GHz (IEEE 802.11b) or 5GHz(IEEE 802.11a) is needed to communicate efficiently in a wireless LAN.

Radiation Pattern

A radiation pattern is a diagram that allows you to visualize the shape of the antenna’s coverage area.

Antenna Gain

Antenna gain, measured in dB (decibel), is the increase in coverage within the RF beam width. Higher antenna gain improves the range of the signal for better communications.

For an indoor site, each 1 dB increase in antenna gain results in a range increase of approximately 2.5%. For an unobstructed outdoor site, each 1dB increase in gain results in a range increase of approximately 5%. Actual results may vary depending on the network environment.

Antenna gain is sometimes specified in dBi, which is how much the antenna increases the signal power compared to using an isotropic antenna. An isotropic antenna is a theoretical perfect antenna that sends out radio signals equally well in all directions. dBi represents the true gain that the antenna provides.

Types of Antennas For WLAN

There are two types of antennas used for wireless LAN applications.

•Omni-directional antennas send the RF signal out in all directions on a horizontal plane. The coverage area is torus-shaped (like a donut) which makes these antennas ideal for a room

Antenna Selection and Positioning Recommendation

E-1

Contents

User's Guide Copyright Federal Communications Commission (FCC) Interference Statement ZyXEL Limited Warranty Customer Support Table of Contents Chapter 5 IP Screen LOGS Chapter 6 Logs Screens Chapter 7 Maintenance Chapter 8 Introducing the SMT Chapter 12 System Information Chapter 13 Firmware and Configuration File Maintenance APPENDICES A-1 B-1 List of Figures Page Page List of Tables Preface User Guide Feedback Part I: OVERVIEW Page Getting to Know Your ZyAIR 1.1Introducing the ZyAIR 1.2ZyAIR Features 10/100M Auto-negotiatingEthernet/Fast Ethernet Interface 10/100M Auto-crossoverEthernet/Fast Ethernet Interface Bridge Power over Ethernet (PoE) 802.11b Wireless LAN Standard Output Power Management WDS Functionality Brute-ForcePassword Guessing Protection SNMP Full Network Management 1.3Applications for the ZyAIR 1.3.1 Infrastructure 1.3.2 Ad Hoc 1.3.3 Bridge Page Introducing the Web Configurator 2.1Accessing the ZyAIR Web Configurator 2.2Navigating the ZyAIR Web Configurator 2.3Resetting the ZyAIR 2.3.1 Method of Restoring Factory-Defaults Part II: SYSTEM, WIRELESS AND IP Page System Screens 3.1System Overview 3.2Configuring General Setup 3.3Configuring Password 3.4Configuring Time Setting Figure 3-3Time Setting Table 3-3Time Setting Wireless LAN 4.1Wireless LAN Basis 4.1.1 Channel 4.1.2 ESS ID 4.1.3 WEP Encryption Page 4.1.5 Fragmentation Threshold 4.2Wireless Security Overview 4.3WEP Overview 4.3.1 Data Encryption 4.3.2 Authentication 4.4Configuring Wireless 4.4.1 Infrastructure Roaming Figure 4-6Wireless : Infrastructure Table 4-1Wireless : Infrastructure 4.4.2 Ad-Hoc Figure 4-7 Ad-hoc(IBSS) Wireless LAN Figure 4-8Wireless : Ad Hoc 4.4.3 Bridge Figure 4-10Bridge Loop: Two Bridges Connected to Hub Figure 4-11Bridge Loop: Bridge Connected to Wired LAN Figure 4-12Wireless : Bridge Table 4-3Wireless : Bridge Page Page IP Screen 5.1Factory Ethernet Defaults 5.2TCP/IP Parameters 5.2.1 IP Address and Subnet Mask 5.3Configuring IP Table 5-2IP You must know the IP address assigned to the ZyAIR (by the DHCP server) to access the ZyAIR again If you change the ZyAIR's IP address, you must use the new IP address if you want to access the web Part III: LOGS Logs Screens 6.1Configuring View Log 6.2Configuring Log Settings Figure 6-2Log Settings Table 6-2Log Settings Page Page Part IV: MAINTENANCE Page Maintenance 7.1Maintenance Overview 7.2System Status Screen 7.2.1 System Statistics 7.3Wireless Screen Figure 7-3Channel Usage Table 7-3Channel Usage 7.4F/W Upload Screen Table 7-4Firmware Upload WARNING Firmware Upload in Process Figure 7-5Firmware Upload In Process 7.5Configuration Screen 7.5.1 Backup Configuration 7.5.2 Restore Configuration Table 7-5Restore Configuration Do not turn off the device while configuration file upload is in progress Figure 7-10Configuration Upload Successful Figure 7-11Network Temporarily Disconnected 7.5.3 Back to Factory Defaults Figure 7-14Reset Warning Message Part V: SMT CONFIGURATION Page Introducing the SMT 8.1Connect to your ZyAIR Using Telnet 8.2Changing the System Password 8.3ZyAIR SMT Menu Overview Example Figure 8-3ZyAIR B-420SMT Menu Overview Example 8.4Navigating the SMT Interface 8.4.1 System Management Terminal Interface Summary Page General Setup 9.1General Setup 9.1.1 Procedure To Configure Menu Table 9-1Menu 1 General Setup LAN Setup 10.1 LAN Setup 10.2 TCP/IP Ethernet Setup 10.3 Wireless LAN Setup Figure 10-3Menu 3.5 Wireless LAN Setup Table 10-2Menu 3.5 Wireless LAN Setup Page 10.3.1 Configuring Bridge Link Table 10-3Menu 3.5.4 Bridge Link Configuration SNMP Configuration 11.1 About SNMP 11.2 Supported MIBs 11.3 SNMP Configuration 11.4 SNMP Traps Table 11-2SNMP Traps Table 11-3Ports and Interface Types System Information 12.1 System Status Figure 12-2Menu 24.1 System Maintenance : Status Table 12-1Menu 24.1 System Maintenance : Status 12.2 System Information 12.2.1 System Information 12.2.2 Console Port Speed 12.3 Log and Trace 12.3.1 Viewing Error Log Page Firmware and Configuration File Maintenance 13.1 Filename Conventions 13.2 Backup Configuration 13.2.1 Backup Configuration Using FTP 13.2.2 Using the FTP command from the DOS Prompt 13.2.3 Backup Configuration Using TFTP 13.2.4 Example: TFTP Command 13.3 Restore Configuration 13.4 Uploading Firmware and Configuration Files 13.4.1 Firmware Upload 13.4.2 Configuration File Upload 13.4.3 Using the FTP command from the DOS Prompt Example 13.4.4 TFTP File Upload 13.4.5 Example: TFTP Command System Maintenance and Information 14.1 Command Interpreter Mode 14.2 Time and Date Setting Part VI: APPENDICES Page Troubleshooting Problems Starting Up the ZyAIR Problems with the Password Problems Communicating with Other Computers Appendix B Brute-ForcePassword Guessing Protection Chart B-1 Brute-ForcePassword Guessing Protection Commands Page Setting up Your Computer’s IP Address Windows 95/98/Me Properties Page Windows 2000/NT/XP Page Page Page Macintosh OS 8/9 Page Macintosh OS Page Page Wireless LAN and IEEE Benefits of a Wireless LAN IEEE Ad-hocWireless LAN Configuration Infrastructure Wireless LAN Configuration Diagram D-2ESS Provides Campus-WideCoverage Page Antenna Selection and Positioning Recommendation Antenna Characteristics Frequency Radiation Pattern Antenna Gain Connector Type Power over Ethernet Specifications Page IP Subnetting IP Addressing IP Classes Subnet Masks Subnetting Example: Two Subnets Page Example: Four Subnets Example Eight Subnets Subnetting With Class A and Class B Networks Page Command Interpreter Command Syntax Command Usage Page Log Descriptions Page Log Commands Log Command Example Power Adaptor Specifications Page Index