D-Link DWL-8500AP Product Manual - Page 158

D-Link Unified Access Point Administrator's Guide Variations on EAP include EAP Cisco Wireless (LEAP), Protected EAP (PEAP), EAP-TLS, and EAP Tunnelled TLS (EAP-TTLS). EDCF Enhanced Distribution Control Function is an extension of DCF. EDCF, a component of the IEEE Wireless Multimedia (WMM) standard, provides prioritized access to the wireless medium. ESS An extended service set (ESS) is an Infrastructure Mode Wireless Networking Framework with multiple access points, forming a single subnetwork that can support more clients than a basic service set (BSS). Each access point supports a number of wireless stations, providing broader wireless coverage for a large space, for example, an office. Ethernet Ethernet is a local-area network (LAN) architecture supporting data transfer rates of 10 Mbps to 1 Gbps. The Ethernet specification is the basis for the IEEE 802.3 standard, which specifies the physical and lower software layers. It uses the CSMA/CA access method to handle simultaneous demands. Ethernet supports data rates of 10 Mbps, Fast Ethernet supports 100 Mbps, and Gigabit Ethernet supports 1 Gbps. Its cables are classified as "XbaseY", where X is the data rate in Mbps and Y is the category of cabling. The original cable was 10base5 (Thicknet or "Yellow Cable"). Some others are 10base2 (Cheapernet), 10baseT (Twisted Pair), and 100baseT (Fast Ethernet). The latter two are commonly supplied using CAT5 cabling with RJ-45 connectors. There is also 1000baseT (Gigabit Ethernet). ERP The Extended Rate Protocol refers to the protocol used by IEEE 802.11g stations (over 20 Mbps transmission rates at 2.4GHz) when paired with Orthogonal Frequency Division Multiplexing (OFDM). Built into ERP and the IEEE 802.11g standard is a scheme for effective interoperability of IEEE 802.11g stations with IEEE 802.11b nodes on the same channel. Legacy IEEE 802.11b devices cannot detect the ERP-OFDM signals used by IEEE 802.11g stations, and this can result in collisions between data frames from IEEE 802.11b and IEEE 802.11g stations. If there is a mix of 802.11b and 802.11g nodes on the same channel, the IEEE 802.11g stations detect this via an ERP flag on the access point and enable request to send (RTS) and clear to send (CTS) protection before sending data. See also CSMA/CA protocol. F Frame A Frame consists of a discrete portion of data along with some descriptive meta-information packaged for transmission on a wireless network. Each frame includes a source and destination MAC address, a control field with protocol version, frame type, frame sequence number, frame body (with the actual information to be transmitted) and frame check sequence for error detection. A Frame is similar in concept to a Packet, the difference being that a packet operates on the Network layer (layer 3 in the OSI model) whereas a frame operates on the DataLink layer (layer 2 in the OSI model). G Gateway A gateway is a network node that serves as an entrance to another network. A gateway also often provides a proxy server and a firewall. It is associated with both a router, which use headers and forwarding tables to determine where packets are sent, and a switch or bridge, which provides the actual path for the packet in and out of the gateway. Before a host on a LAN can access the Internet, it needs to know the address of its default gateway. 158 © 2001-2008 D-Link Corporation. All Rights Reserved.