October 2012
Intermediate to advanced
160 pages
2h 49m
Chinese
Content preview from 802.11n技術手冊
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第五章
然而，有一些早期的 802.11n 產品實作了一個 802.11n 相容版本的 TKIP。因此 Wi-Fi 聯
盟的 802.11n 認證計畫開始進行陰性測試，以避免使用 TKIP 於 802.11n 資料速率。許多
802.11n 產品保留 TKIP 於一個「傳統」模式，其資料速率被限制在 802.11a/b/g 的速率，
以繼續使用 TKIP。
TKIP 與 WEP 是不允許在 802.11n 中使用的，並且在 Wi-Fi 聯盟的測試中
是被禁止的，而 802.11a/b/g 設備仍然允許使用 TKIP。許多經認證的 11n
設備實作了 TKIP 與 WEP，但禁止使用於 11n 速率。
強制性的鏈結層特性
為了幫助讀者記錄強制性與選用性的特性，表 5-4 將協定特性分為兩類。一般來說，
Wi-Fi 聯盟的測試計畫所驗證的功能性在規範中是強制性的，而選用性測試僅針對最廣
為支援的特性。
表 5-4 MAC 特性分類
特性 強制 / 選用 註釋
A-MPDU 接收 強制 需測試於 Wi-Fi 聯盟測試計畫
A-MPDU 傳送 選用 Wi-Fi 聯盟測試計畫中選用測試並顯示於互通性認證
A-MSDU 接收 強制 需測試於 Wi-Fi 聯盟測試計畫
A-MSDU 傳送 選用 不需測試於 Wi-Fi 聯盟測試計畫
區塊回應 強制 除了基本需求外，802.11n 增加了對壓縮區塊回應的支援
保護 強制 如 CTS-to-self 這類基本保護機制是必要的，但 L-SIG 欺
騙選項則是選用的
RIFS
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