Cabletron Systems 3Com manual Site Surveys

Page 17

Theory of Operation 17

Site Topography For optimal performance, place wireless clients and APs away from transformers, heavy-duty motors, fluorescent lights, microwave ovens, refrigerators and other industrial equipment.

Signal loss can occur when metal, concrete, brick, walls or floors block transmission.

Locate antennas in open areas or add additional APs as needed to improve coverage.

Site Surveys

A site survey analyzes the installation environment and provides users with recommendations for the number and placement of APs. 3Com recommends that a site survey be conducted at any new site prior to installing AirConnect equipment.

Theory of Operation To improve AP management and performance, you should understand basic AP functionality and configuration options. The AP includes features for different interface connections and network management.

The AP provides MAC layer bridging between its interfaces. The AP monitors traffic from its interfaces and, based on frame address, forwards the frames to the proper destination. The AP tracks the frames sources and destinations to provide intelligent bridging as wireless clients roam or network topologies change. The AP also handles broadcast and multicast message initiations and responds to wireless client association requests.

MAC Layer Bridging The AP listens to all packets on all interfaces and builds an address database using the unique IEEE 48-bit address (MAC address). An address in the database includes the interface media that the device uses to associates with the AP. (The AP internal stack interface handles all messages directed to the AP.) The AP uses the database to forward packets from one interface to another. The bridge forwards packets addressed to unknown systems to the default interface (either Ethernet or PPP).

Each AP stores information on destinations and their interfaces to facilitate forwarding. When you send an Address Resolution Protocol (ARP) request packet, the AP forwards the request over all enabled interfaces (Ethernet, PPP, or radio), except over the interface on which the ARP request packet was received. (Radio-received ARP request packets echo back to other APs over radio.) Upon receiving the ARP response packet, the AP database keeps a record of the destination address along with the receiving interface. With this information, the AP forwards any directed packet to the correct destination. The AP forwards packets for unknown destinations to the Ethernet interface.

The AP removes from its database destinations or interfaces not used for a specified time. The AP refreshes its database when it transmits or receives data from these destinations and interfaces.

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Contents Version AirConnect 11 Mbps Wireless LAN Access Point User GuideBayfront Plaza Santa 3Com CorporationClara, California 95052-8145Contents Installing Access Point Hardware Monitoring Wireless Clients Access Point Installation Configuring the AP Access Point Specifications Technical Support Page Introduction Overview of Digital Wireless NetworkingAirConnect Network TopologiesOverview of Digital Wireless Networking AirConnect Network Topologies Wireless clients AirConnect AccessPoint To the Ethernet LANAirConnect Access Point Wireless clients and APs PowerBASE-TRadio Basics Results in the original digital dataRadio Basics 802.1d Spanning Tree Support Wireless LAN Service AreaSite Surveys Filtering and Access Control Network Control Protocol NCP as described PPP Connection Data Rate Requirement Overview of Digital Wireless Networking Theory of Operation Simple Network Management Protocol Snmp Programmable Snmp Trap Support Using SnmpManagement protocol MIB Increased MIB SupportMethod Description Using the User InterfacePrecautions Installing Access Point HardwarePackage Contents RequirementsStandard power supply 115/230VAC, 50/60Hz, 24V/14 Power OptionsRemote power distribution system, Part Number AP-PS-11 US line cord Part NumberWall Mount To mount an AP on a wall Mounting the APBelow Ceiling Mount To mount an AP on a ceiling Mounting the AP PowerBASE-T can be used to power the AP UsingPowerBASE-T Condition, and other activity LED IndicatorsOff Blinking Power No power Power on During boot sequence 3Com Support Center TroubleshootingVerify AP Operation Electrical Management System EMS operating outletNetwork connection verification Verify Network Wiring TopologyPage System Properties Monitoring StatisticsInterface Statistics Forwarding CountsStatistics Ethernet StatisticsRadio Frequency Statistics window, select Main Menu→Misc Statistics MiscellaneousPress Esc or Previous F4 to exit Type Name DefinitionSelect Clear All Statistics Clearing StatisticsKnown APs Gaining access to the User Interface UI Gaining Access to the User Interface UI Using a Web BrowserHelp File Access Setup Network Web Server Help File AccessSelect Virtual Directory Accessing the Web Browser UISelect Close/Exit Select System ConfigurationSelect Save F1 to save the configuration Select Special Functions Select Reset APType the case sensitive AP name Under Configuration, select Security Select System PasswordParameter Description Select Easy Setup--Easy SetupSelect Easy Setup--Easy Setup Click Add/Delete Gateways Adding or Deleting Disallowed Wireless Clients Adding Allowed Wireless ClientsAdding or Deleting a Range of Allowed Wireless Clients Considerations For the Short RF Preamble setting, click DisabledEnabling or Disabling Encryption Select Configuration--SecurityFrequency No. of Channels Country Enable or disable interfaces on the APInterface Description Default Condition Enter the Multicast Mask data and voice values Snmp Trap Description Default Value Select Enabled or Disable All for All Snmp TrapsConfiguring the Originating Modem Filtering to Discard Packets Configuring the Answering ModemFiltering to Forward Packets Click Delete Filter Removing Filtered Packet Types Networking ProtocolsDisabling Type Filtering Under Configuration, select FirmwareSpecial Function Description Active. Clear the wireless client association table forSelect Regular at the Wireless Clients prompt Monitoring Wireless ClientsWireless Clients Indicates a 3Com voice-enabled device Versions Ascii InterfaceLatest version. Refer to Manually Updating AP Firmware on Arrow/Function Key Control Character Enable serial portConfigure the AP for the following Prompt Description To exit from submenus, press EscPress Tab to select System Password Select Telnet LoginsTo enable and configure the serial port connection on the AP Configuring The Serial PortConfiguring the Dial-Up System Setting DescriptionHanging Up Select Modem HangupWindow InstallationConfiguring the AP That can associate with this AP. The default is Disabled Wsaid PPP with Modems PPP DirectEstablishing a Connection Originating AP Set the Connect Mode to AnswerAnswering AP From the answering APs UIFor automatic dial-out, reset the AP Press up/down arrows to toggle between range and individual Range of Wireless ClientsRemoving All Allowed Wireless Clients Removing Allowed Wireless ClientsEnable/Disable the ACL Adding Disallowed Wireless Clients Load ACL from Wireless Client ListRemoving Disallowed Wireless Clients Address FilteringSetting Logging Clearing WirelessClients from the AP OptionsPrevious version of AP firmware Manually UpdatingAP Firmware Type the firmware file name in the Download Filename field Remainder of this procedure uses Windows 98 as an exampleSelect Alter Filenames/HELP URL/TFTP and press Enter Select Send File Open the Special Functions windowSelect Transfer from the emulation program menu bar Select Alter Filenames/HELP URL/TFTP Server and press Enter Download is complete when the UI displaysAuthentication Using MD5Performing Pings Extended RoamingHex-digit sequence Wireless client and the access pointEncryption Restoring Configurations Press the Tab key to highlight .Short RF Preamble EnabledSelect Restore Factory Configuration Physical Characteristics Access Point SpecificationsRadio Characteristics Frequency No. of Channels Country Output CharacteristicsNetwork Characteristics Technical Support ServicesOnline Technical World Wide Web SiteNorth America Latin AmericaTo obtain an RMA number, call or fax Page Ascii IndexSnmp agent 3Com AirConnect Access Point 3Com Corporation Limited WarrantyObtaining Warranty Radio Frequency Interference Requirements Canada Regulatory Compliance Information3Com End User Software License Agreement Important Read Before Using This Product
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