You can view the full version and download it in PDF format.
Page 69 of 69
CNet Global Technology Inc.
5.29 What is WLAN Block Relay between Clients?
An Infrastructure Basic Service Set is a BSS with a component called an Access Point (AP). The access point provides a
local relay function for the BSS. All stations in the BSS communicate with the access point and no longer communicate di-
rectly. All frames are relayed between stations by the access point.
This local relay function effectively doubles the range of the IBSS.
5.30 What is WMM?
WMM is based on a subset of the IEEE 802.11e WLAN QoS draft standard. WMM adds prioritized capabilities to Wi-Fi
networks and optimizes their performance when multiple concurring applications, each with different latency and through-
put requirements, compete for network resources. By using
WMM, end-user satisfaction is maintained in a wider variety of environments and traffic conditions.
WMM makes it possible for home network users and enterprise network managers to decide which data streams are most
important and assign them a higher traffic priority.
5.31 What is WLAN ACK TIMEOUT?
ACK frame has to receive ACK timeout frame. If remote does not receive in specified period, it will be retransmitted.
5.32 What is Modulation Coding Scheme (MCS)?
MCS is Wireless link data rate for 802.11n. The throughput/range performance of an AP will depend on its implementation
of coding schemes. MCS includes variables such as the number of spatial streams modulation, and the data rate on each
stream. Radios establishing and maintaining a link must automatically negotiate the optimum MCS based on channel con-
ditions and then continuously adjust the selection of MCS as conditions change due to interference, motion, fading, and
5.33 What is Frame Aggregation?
Every 802.11 packet, no matter how small, has a fixed amount of overhead associated with it. Frame Aggregation combines
multiple smaller packets together to form one larger packet. The larger packet can be sent without the overhead of the indi-
vidual packets. This technique helps improve the efficiency of the 802.11n radio allowing more end user data to be sent in a
5.34 What is Guard Intervals (GI)?
A GI is a period of time between symbol transmission that allows reflections (from multipath) from the previous data
transmission to settle before transmitting a new symbol. The 802.11n draft specifies two guard intervals: 400ns (short) and
800ns (long). Support of the 400ns GI is optional for transmit and receive. The purpose of a guard interval is to introduce
immunity to propagation delays, echoes, and reflections to which digital data is normally very sensitive.
This manual is suitable for devices