NETGEAR CG814M manual Wireless Channel Selection, Table B-1 802.11b Radio Frequency Channels

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Reference Manual for the Model CG814M Wireless Cable Modem Gateway

The 128-bit WEP data encryption method consists of 104 user-configurable bits. Similar to the forty-bit WEP data encryption method, the remaining 24 bits are factory set and not user configurable. Some vendors allow passphrases to be entered instead of the cryptic hexadecimal characters to ease encryption key entry.

Wireless Channel Selection

IEEE 802.11b wireless nodes communicate with each other using radio frequency signals in the ISM (Industrial, Scientific, and Medical) band between 2.4Ghz and 2.5Ghz. Neighboring channels are 5Mhz apart. However, due to spread spectrum effect of the signals, a node sending signals using a particular channel will utilize frequency spectrum 12.5Mhz above and below the center channel frequency. As a result, two separate wireless networks using neighboring channels (for example, channel 1 and channel 2) in the same general vicinity will interfere with each other. Applying two channels that allow the maximum channel separation will decrease the amount of channel cross-talk, and provide a noticeable performance increase over networks with minimal channel separation.

The radio frequency channels used are listed in Table B-1:

Table B-1.	802.11b Radio Frequency Channels

Channel	Center Frequency	Frequency Spread

1	2412Mhz	2399.5Mhz - 2424.5Mhz

2	2417Mhz	2404.5Mhz - 2429.5Mhz

3	2422Mhz	2409.5Mhz - 2434.5Mhz

4	2427Mhz	2414.5Mhz - 2439.5Mhz

5	2432Mhz	2419.5Mhz - 2444.5Mhz

6	2437Mhz	2424.5Mhz - 2449.5Mhz

7	2442Mhz	2429.5Mhz - 2454.5Mhz

8	2447Mhz	2434.5Mhz - 2459.5Mhz

9	2452Mhz	2439.5Mhz - 2464.5Mhz

10	2457Mhz	2444.5Mhz - 2469.5Mhz

11	2462Mhz	2449.5Mhz - 2474.5Mhz

12	2467Mhz	2454.5Mhz - 2479.5Mhz

13	2472Mhz	2459.5Mhz - 2484.5Mhz

B-14	Networks, Routing, and Firewall Basics

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Contents NETGEAR, Inc Trademarks World Wide Web Page Contents USB Appendix a Appendix C Contents Contents About This Manual AudienceTypographical Conventions Special Message Formats Technical SupportKey Features Chapter IntroductionAbout the CG814M Gateway Built-in Cable ModemPowerful, True Firewall Content Filtering802.11b Standards-based Wireless Networking Configurable Auto Uplink Ethernet Connection USB PortProtocol Support Easy Installation and Management What’s in the Box? Firewall’s Front PanelLED Descriptions Gateway’s Rear Panel CG814M Gateway Rear PanelIntroduction Connecting the Gateway to the Internet What You Will Need Before You BeginLAN Hardware Requirements Computer RequirementsLAN Configuration Requirements Internet Configuration RequirementsWhere Do I Get the Internet Configuration Parameters? Connecting the Gateway to the Internet Record Your Internet Connection Information Connecting the CG814M Gateway Connecting to Your ComputerEthernet USBConnecting to your Cable Service Provider WirelessConnecting the Power Adapter Log in to the GatewayLogin window opens as shown in -3below Connect to the Internet Connecting the CG814M Gateway to the Internet ConfigurationConnecting the Gateway to the Internet Connecting the Gateway to the Internet Connecting the Gateway to the Internet Chapter Wireless Configuration Considerations For a Wireless NetworkSecurity Wireless Settings Placement and RangeWireless Settings Restricting Wireless Access by MAC AddressConfiguring Wired Equivalent Privacy WEP Wireless Configuration Wireless Configuration Protecting Access to Your CG814M Gateway Changing the Built-In PasswordChapter Protecting Your Network Blocking Keywords, Sites, and Services Set Password menuBlock Keywords and Domains Click on the Block Sites link of the Content Filtering menu Blocking Services ProxyPort Blocking CookiesPort Forwarding Port Blocking menuTo forward inbound traffic Port Triggering Considerations for Port ForwardingTo configure Port Triggering Setting Up a Default DMZ Host Respond to Ping on Internet WAN PortProtecting Your Network Chapter Managing Your Network Network Status InformationViewing Gateway Status This screen shows the following parametersMenu 3.2 Router Status Fields Connection Status Connection screenConfiguring LAN IP Settings LAN IP SetupCurrent System Time Dhcp Use router as Dhcp serverViewing and Emailing Logged Information Logs menuErasing Configuration Enabling Logs Event E-mail NotificationRunning Diagnostic Utilities Diagnostics menuManaging Your Network Chapter Troubleshooting Basic FunctionsPower LED Not On Test LED Stays OnLocal Link LEDs Not On Troubleshooting the Web Configuration Interface Cable Link LED Not OnTroubleshooting the ISP Connection Troubleshooting a TCP/IP Network Using a Ping UtilityTesting the LAN Path to Your Gateway Testing the Path from Your PC to a Remote Device Troubleshooting Appendix a Technical Specifications TCP/IPTechnical Specifications Appendix B Networks, Routing, and Firewall Basics Related Publications Basic Router ConceptsWhat is a Router? Routing Information ProtocolIP Addresses and the Internet Three Main Address Classes Netmask EqualsSubnet Addressing Example of Subnetting a Class B AddressNetmask Notation Translation Table for One Octet Private IP Addresses Single IP Address Operation Using NAT Single IP Address Operation Using NATMAC Addresses and Address Resolution Protocol Related DocumentsIP Configuration by Dhcp Internet Security and FirewallsDomain Name Server What is a Firewall? Denial of Service AttackStateful Packet Inspection Wireless Networking Wireless Network ConfigurationAd-hoc Mode Peer-to-Peer Workgroup Infrastructure ModeExtended Service Set Identification Essid Authentication and WEP EncryptionWireless Channel Selection Table B-1 802.11b Radio Frequency ChannelsUplink Switches and Crossover Cables Ethernet CablingCable Quality Appendix C Preparing Your Network Preparing Your Computers for TCP/IP NetworkingConfiguring Windows 95, 98, and ME for TCP/IP Networking Install or Verify Windows Networking ComponentsPreparing Your Network Enabling Dhcp to Automatically Configure TCP/IP Settings Selecting Windows’ Internet Access MethodConfiguring Windows NT, 2000 or XP for IP Networking Verifying TCP/IP PropertiesConfiguring the Macintosh for TCP/IP Networking MacOS 8.6 orMacOS Verifying TCP/IP Properties for Macintosh Computers What Is Your Configuration Information? Verifying the Readiness of Your Internet AccountMail.xxx.yyy.com Preparing Your Network Restarting the Network Glossary Networks See Network Address Translation Connection