{"id":88,"date":"2012-11-16T19:43:51","date_gmt":"2012-11-16T21:43:51","guid":{"rendered":"http:\/\/efagundes.com\/openclass_networking\/?page_id=88"},"modified":"2022-01-16T17:49:49","modified_gmt":"2022-01-16T20:49:49","slug":"wireless-lan","status":"publish","type":"page","link":"https:\/\/efagundes.com\/networking\/hardware-de-rede\/wireless-lan\/","title":{"rendered":"Wireless LAN"},"content":{"rendered":"<p><a href=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide20.jpg\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"2327\" data-permalink=\"https:\/\/efagundes.com\/networking\/hardware-de-rede\/wireless-lan\/slide20\/\" data-orig-file=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide20.jpg?fit=960%2C720&amp;ssl=1\" data-orig-size=\"960,720\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Slide20\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide20.jpg?fit=960%2C720&amp;ssl=1\" class=\"alignnone size-full wp-image-2327\" src=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide20.jpg?resize=960%2C720\" alt=\"Slide20\" width=\"960\" height=\"720\" srcset=\"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide20.jpg?w=960&amp;ssl=1 960w, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide20.jpg?resize=300%2C225&amp;ssl=1 300w\" sizes=\"auto, (max-width: 960px) 100vw, 960px\" \/><\/a><\/p>\n<p>Antes de 1998, instalar uma rede sem fio significava uso de uma ou mais solu\u00e7\u00f5es propriet\u00e1rias. As conex\u00f5es eram feitas atrav\u00e9s de redes pouco confi\u00e1veis, com baixas taxas de transmiss\u00e3o e a com um m\u00ednimo de seguran\u00e7a. O resultado do esfor\u00e7o de padroniza\u00e7\u00e3o levou a cria\u00e7\u00e3o dos padr\u00f5es HiperLAN\/2, IEEE 802.11b e Bluetooth. Esse esfor\u00e7o de especifica\u00e7\u00e3o assegurou que todos os equipamentos pudessem se comunicar utilizando os mesmos protocolos e interfaces de comunica\u00e7\u00e3o.<\/p>\n<p>No esfor\u00e7o de resolver os problemas de incompatibilidade das WLANs, a organismos de padroniza\u00e7\u00e3o tem planos para certificar todas as vers\u00f5es do IEEE 802.11 para os equipamentos do mercado, removendo todas as barreiras de d\u00favidas do mercado. Todos equipamentos certificados dever\u00e3o levar o selo de Wireless Fidelity (Wi-Fi).<\/p>\n<p>O IEEE 802.11b \u00e9 especificado para operar em 2,4-GHz utilizando a banda ISM (Industrial, Scientific and Medical band). Os canais de r\u00e1dio freq\u00fc\u00eancia usam a modula\u00e7\u00e3o DSSS (Direct Sequence Spread Spectrum), permitido altas taxas de velocidade em dist\u00e2ncias de at\u00e9 50 metros em escrit\u00f3rios. O padr\u00e3o permite taxas de transfer\u00eancia de at\u00e9 11-Mbps, que s\u00e3o at\u00e9 cinco vezes maiores do que a especifica\u00e7\u00e3o original do IEEE 802.11 e pr\u00f3xima ao padr\u00e3o Ethernet.<\/p>\n<p>Tipicamente, o padr\u00e3o IEEE 802.11b \u00e9 utilizado em pequenos escrit\u00f3rios, em hospitais, em dep\u00f3sitos e em ch\u00e3o de f\u00e1brica. Seu principal uso dever\u00e1 ser em grandes campi para prover conectividade em salas de confer\u00eancias, \u00e1reas de trabalhos, e qualquer outro ambiente inconveniente ou perigoso para se instalar cabos. No curto prazo, em qualquer ambiente onde exista a necessidade de mobilidade ser\u00e1 aceit\u00e1vel a instala\u00e7\u00e3o de rede sem fios.<\/p>\n<p>Usando um protocolo estendido, o 802.11g permite o uso misto da rede. Esta caracter\u00edstica de uso misto permite que equipamentos que usam o 802.11b operando em 11-Mbps possam compartilhar a mesma rede com os novos equipamentos operando em 54-Mbps. Isso permitir\u00e1 a migra\u00e7\u00e3o sem impacto das redes de 11-Mbps para as redes de 54-Mbps.<\/p>\n<p>O padr\u00e3o 802.11n para frequ\u00eancia 2,4 GHz e\/ou 5 GHz tem capacidade de 65 a 600 Mbps. Esse padr\u00e3o utiliza como m\u00e9todo de transmiss\u00e3o MIMO-OFDM (Orthogonal frequency-division multiplexing).<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Antes de 1998, instalar uma rede sem fio significava uso de uma ou mais solu\u00e7\u00f5es propriet\u00e1rias. As conex\u00f5es eram feitas atrav\u00e9s de redes pouco confi\u00e1veis, com baixas taxas de transmiss\u00e3o e a com um m\u00ednimo de seguran\u00e7a. O resultado do esfor\u00e7o de padroniza\u00e7\u00e3o levou a cria\u00e7\u00e3o dos padr\u00f5es HiperLAN\/2, IEEE 802.11b e Bluetooth. Esse esfor\u00e7o [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":61,"menu_order":0,"comment_status":"closed","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-88","page","type-page","status-publish","hentry"],"jetpack_shortlink":"https:\/\/wp.me\/P8yKGp-1q","jetpack-related-posts":[{"id":503,"url":"https:\/\/efagundes.com\/networking\/multiplexacao-2\/sdh-capacidade-de-transporte\/","url_meta":{"origin":88,"position":0},"title":"SDH &#8211; Capacidade de transporte","author":"Eduardo Fagundes","date":"17\/11\/2012","format":false,"excerpt":"Vantagens e Restri\u00e7\u00f5es As redes SDH oferecem v\u00e1rios benef\u00edcios, quando comparada com outras tecnologias: O cabe\u00e7alho complexo existente no frame SDH permite a ger\u00eancia (administra\u00e7\u00e3o, opera\u00e7\u00e3o e manuten\u00e7\u00e3o) centralizada da rede; A arquitetura de multiplexa\u00e7\u00e3o s\u00edncrona e a padroniza\u00e7\u00e3o tanto em n\u00edvel de equipamentos como de interfaces, permite o crescimento\u2026","rel":"","context":"Post similar","block_context":{"text":"Post similar","link":""},"img":{"alt_text":"Slide12","src":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide125.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide125.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide125.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide125.jpg?resize=700%2C400 2x"},"classes":[]},{"id":637,"url":"https:\/\/efagundes.com\/networking\/ethernet-2\/o-padrao-ieee-802-2-llc\/","url_meta":{"origin":88,"position":1},"title":"O padr\u00e3o IEEE 802.2: LLC","author":"Eduardo Fagundes","date":"17\/11\/2012","format":false,"excerpt":"O padr\u00e3o ANSI\/IEEE 802.2 (ISO 8802-2) descreve as fun\u00e7\u00f5es da camada de controle l\u00f3gico de enlace (LLC) do padr\u00e3o IEEE 802 (ISO 8802-2), comum aos v\u00e1rios m\u00e9todos de acesso definidos na fam\u00edlia de padr\u00f5es IEEE 802, bem como a interface oferecida pela camada LLC para o n\u00edvel de rede e\u2026","rel":"","context":"Post similar","block_context":{"text":"Post similar","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide323.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide323.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide323.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide323.jpg?resize=700%2C400 2x"},"classes":[]},{"id":663,"url":"https:\/\/efagundes.com\/networking\/lans-sem-fio\/ieee-802-16\/","url_meta":{"origin":88,"position":2},"title":"IEEE 802.16","author":"Eduardo Fagundes","date":"17\/11\/2012","format":false,"excerpt":"O padr\u00e3o 802.16 \u00e9 tamb\u00e9m conhecido como a interface a\u00e9rea da IEEE para Wireless MAN, isto \u00e9, da rede metropolitana sem fios. Esta tecnologia est\u00e1 sendo especificada pelo grupo do IEEE que trata de acessos de banda larga para \u00faltima milha em \u00e1reas metropolitanas, com padr\u00f5es de desempenho equivalentes aos\u2026","rel":"","context":"Post similar","block_context":{"text":"Post similar","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide441.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide441.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide441.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/efagundes.com\/networking\/wp-content\/uploads\/sites\/5\/2015\/03\/Slide441.jpg?resize=700%2C400 2x"},"classes":[]},{"id":92,"url":"https:\/\/efagundes.com\/networking\/hardware-de-rede\/interconexao-de-sistemas\/","url_meta":{"origin":88,"position":3},"title":"Interconex\u00e3o de sistemas","author":"Eduardo Fagundes","date":"16\/11\/2012","format":false,"excerpt":"Est\u00e3o sendo desenvolvidas redes sem fio geograficamente distribu\u00eddas de alta largura de banda. 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