From sradvan at fedoraproject.org Wed Jun 10 16:01:26 2015 Content-Type: multipart/mixed; boundary="===============2986790765778124897==" MIME-Version: 1.0 From: sradvan To: docs-commits at lists.fedoraproject.org Subject: r146 - community/trunk/en-US Date: Thu, 01 Jul 2010 04:13:43 +0000 Message-ID: <20100701041343.8111112027B@lists.fedorahosted.org> --===============2986790765778124897== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Author: sradvan Date: 2010-07-01 04:13:41 +0000 (Thu, 01 Jul 2010) New Revision: 146 Modified: community/trunk/en-US/Communication.xml Log: Modified: community/trunk/en-US/Communication.xml =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- community/trunk/en-US/Communication.xml 2010-07-01 01:38:18 UTC (rev 14= 5) +++ community/trunk/en-US/Communication.xml 2010-07-01 04:13:41 UTC (rev 14= 6) @@ -4,23 +4,30 @@ = Wireless Communication - - stuff = -
Data Rates and Throughput - Several metrics and measurements are used to define elements of wirele= ss LANs. Some of these include terms to define data rate, throughput, signa= l to noise ratio, antenna gain, signal loss and encryption strength. One co= mmonly misunderstood set of measurements is data rate = and throughput. To use the IEEE 802.11g standard as an= example, it is often referred to and marketed as having a 54Mbps (megabits= /s) connection speed. This is however only a theoretical maximum speed unde= r perfect conditions defined in the standard. Unfortunately, the real world= is not a perfect environment, and in some cases can be outright hostile to= facilitating wireless communication. + Several metrics and measurements are used to define elements of a WLAN= , such as data rate, throughput, signal to noise ratio (SNR), antenna gain,= signal loss and encryption strength. One commonly misunderstood concept is= the relationship between data rate and thro= ughput. - Continuing to use the IEEE 802.11g standard to define these terms, the= standard is actually capable of negotiating its connection with other devi= ces at several different data rates. This ability to c= hange data rates is known as Dynamic Rate Switching, and= a properly functioning card will negotiate the best possible speed dependi= ng on the distance from the Access Point, the amount and type of other devi= ces that are connecting, and overall environmental conditions. = + To use the IEEE 802.11g standard as an example, which is often referre= d to and marketed as having a 54Mbps (megabits/s) connection speed, this is= only a theoretical maximum speed under perfect conditions defined in the s= tandard. Unfortunately, the real world is not a perfect environment, and in= some cases can be outright hostile to facilitating wireless communication. - The IEEE 802.11g standard can operate under the following data ra= tes: 6, 9, 12, 18, 24, 36, 48 and 54 Mbps, and can use 802.11b speeds if in= a mixed-mode environment. This series of speeds, and the current connected= rate is usually intepreted in a graphical form in your operating system as= a graph or bar or other text, representing signal strength (this is known = as the Received Signal Strength Indicator). So, while th= e standard defines 54Mbps as the maximum speed, the data rate is actually n= egotiating one of the above speeds based on environmental conditions. This = data rate is related to, but different from the actual amount of network data coming through the connection at any given time. Th= is actual data transfer speed is known as throughput. + + The full 54Mbps throughput as defined in the standard never be achieve= d in the real world. Your actual throughput of network data is typically 15= % to 40% of this marketed level. Data rate is the nego= tiated, variable, maximum possible link to other devices, and thr= oughput is the real-world, measured amount of actual data flow. +
+
+Dynamic Rate Switching - As mentioned, the full 54Mbps throughput as defined in the standard ca= n never be achieved in the real world. Your actual throughput of network da= ta is typically 15-40% of this maximum level. Data rate is the negotiated, variable, maximum possible link to other devices, and = throughput is the real-world speed of actual data flow. + Continuing to use the IEEE 802.11g standard to define these terms, a w= ireless client is capable of negotiating its connection with other devices = at several different data rates. This ability to chang= e data rates is known as Dynamic Rate Switching, and a p= roperly functioning client will be able to negotiate the best possible, the= oretical speed depending on the distance from the Access Point, the amount = and type of other devices that are connecting, and overall environmental co= nditions. The IEEE 802.11g standard can operate under the following data r= ates: 6, 9, 12, 18, 24, 36, 48 and 54 Mbps, and can use 802.11b data rates = if in a mixed-mode environment. =
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+Received Signal Strength Indicator + +This series of speeds used in Dynamic Rate Switching, and the current conn= ected rate is usually intepreted in some sort of graphical form in your ope= rating system as a graph or bar or other explanatory text. This is known as= the Received Signal Strength Indicator (RSSI). + +
Connection Modes --===============2986790765778124897==--