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Glossary of Terms 269
Appendix B: Glossary of Terms
Term Definition
802.11x Refers to a family of specifications developed by the IEEE for wireless LAN technology.
802.11 specifies an over-the- air interface between a wireless client and a base station,
or between two wireless clients. The IEEE accepted the specification in 1997. There are
several specifications in the 802.11 family:
802.11 Applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band
using either Frequency Hopping Spread Spectrum (FHSS) or Direct Sequence Spread
Spectrum (DSSS).
802.11a An extension to 802.11 that applies to wireless LANs and provides up to 54 Mbps in
the 5GHz band. 802.11a uses an Orthogonal Frequency Division Multiplexing (OFDM)
encoding scheme rather than FHSS or DSSS.
802.11b (also referred to as 802.11 High Rate or Wi-Fi™) An extension to 802.11 that applies to
wireless LANs and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1
Mbps) in the 2.4 GHz band. 802.11b uses only DSSS. 802.11b was a 1999 ratification to
the original 802.11 standard, allowing wireless functionality comparable to Ethernet.
802.11g Applies to wireless LANs and provides 20+ Mbps in the 2.4 GHz band.
802.1Q An IEEE standard for providing a virtual LAN capability within a campus network.
802.1Q establishes a standard format for frame tagging (Layer 2 VLAN markings),
enabling the creation of VLANs that use equipment from multiple vendors.
10/100 Ethernet See Ethernet.
AAA
(Authentication, Authorization, and Accounting) A combination of commands used by
Nomadix Gateways to authenticate, authorize, and subsequently bill subscribers for
their use of the customer’s network. When a subscriber logs into the system, their
unique MAC address is placed into an authorization table. The system then
authenticates the subscriber’s MAC address and billing information before allowing
them to access the Internet and make online purchases. See also, MAC Address.
Access Concentrator
A type of multiplexer that combines multiple channels onto a single transmission
medium in such a way that all the individual channels can be simultaneously active. For
example, ISPs use concentrators to combine their dial-up modem connections onto
faster T-1 lines that connect to the Internet. Concentrators are also used in Local Area
Networks (LANs) to combine transmissions from a cluster of nodes. In this case, the
concentrator is often called a hub.
Access Router A router at a customer site, which connects to the network service provider. Also
known as a Customer Premises Equipment (CPE) router. See also, Router.
ACK (ACKnowledgment) If all the transmitted data is present and correct, the receiving
device sends an ACK signal, which acts as a request for the next data packet.