Network Allocation Vector. The NAV is used to implement the virtual carrier sensing function. Stations will defer access to the medium if it is busy. For robustness, 802.11 includes two carrier-sensing functions. One is a physical function, which is based on energy thresholds, whether a station is decoding a legal 802.11 signal, and similar things that require a physical measurement. The second function is a virtual carrier sense, which is based on the NAV. Most frames include a nonzero number in the NAV field, which is used to ask all stations to politely defer from accessing the medium for a certain number of microseconds after the current frame is transmitted. Any receiving stations will process the NAV and defer access, which prevents collisions. For more detail on how the NAV is used, see Section 3.7 in Chapter 3.

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DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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