Cabletron Systems 3Com manual Simple Network Management Protocol SNMP, Protocol or Scheme

24CHAPTER 1: OVERVIEW OF DIGITAL WIRELESS NETWORKING

them to the wireless client and the wireless client goes back to sleep. A DTIM field, also called a countdown field, informs wireless clients of the next window for listening to broadcast and multicast messages. The AP sends the messages following the nth beacon where n is the DTIM interval defined in the AP. When the AP has buffered broadcast or multicast messages for associated wireless clients, it sends the next DTIM with a DTIM Interval value. This value decreases by '1' with each successive beacon. The AP sends broadcast and multicast messages immediately following the beacon where the DTIM value is '0.' To prevent a PSP-mode wireless client from sleeping through a DTIM notification, select a PSP mode value less than or equal to the DTIM value. PSP-mode wireless clients hear the beacons and awaken to receive the broadcast and multicast messages.

A TIM is a compressed virtual bitmap identifying the AP associated wireless clients in PSP mode that have buffered directed messages. wireless clients issue a poll request when APs issue a TIM. A beacon with the broadcast-indicator bit set causes the wireless client to note DTIM Count field value. The value informs the wireless client of the beacons remaining before next DTIM. This ensures the wireless client turns on the receiver for the DTIM and the following BC/MC packet transmissions.

HTTP, HTML Web Server Hypertext Transfer Protocol (HTTP) is the native language of the World Wide Web. Support The HTTP protocol makes requests from browsers to servers and responses from

servers to browsers. This function provides the user with a Web-based format for configuration and firmware download.

Web pages are written in Hypertext Markup Language (HTML). HTML allows the user to create Web pages containing text, graphics, and pointers or links to other Web pages or elsewhere on the page or document. Pointers are known as Uniform Resource Locators (URLs). A URL is essentially the name of the Web page. The URL consists of three parts:

1Protocol (or Scheme)

2Fully Qualified Domain Name (FQDN), the machine where the page is located

3Local name that identifies the page (usually the HTML file name).

The HTML language describes how to format the document, indication which fonts to use, much like a copy editor describes which fonts to use, such as the location, color, header size and text.

Management Options Managing AirConnect includes viewing network statistics and setting configuration options. Statistics track the network activity of associated wireless clients and data transfers on the AP interfaces. Configuration involves, among other things, setting system operating parameters and filters used in bridging.

The AP requires one of the following to perform a custom installation or maintain the AirConnect network:

■Simple Network Management Protocol (SNMP).

■Wired or wireless LAN workstation with a telnet client.

■Terminal or PC with RS-232 connection and access to ANSI emulation.