October 2012
Intermediate to advanced
160 pages
2h 49m
Chinese
Content preview from 802.11n技術手冊
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
設計與建置一個 802.11n 網路
|
123
執行 Wireshark 需要系統層級的權限來讀取封包。在 MacOS 和 Linux 上，
請確認使用者在執行 Wireshark 時的 BPF 裝置是可讀的狀態。
當在進行訊框分析時，你的分析器將會從無線介面讀取訊框並且顯示其內容。更重要的
是，訊框只能是藉由你的分析器收到的才是可用的。分析器可以透過乙太網路來連接，
在連接埠映射（Port mirroring）程式中排除一些不尋常的問題或者是錯誤，在接收訊框
上不會有問題。而在無線網路中，分析器只接收它可以解碼的訊框。為了排除客戶端的
問題，往往需要將分析器實體上移到發生問題的設備旁來設置。在理想情況下，你的分
析工具將使用與客戶端設備相同的晶片組，因此它有相似的效能特性，但在大多數情況
下不是必要的。
部分 AP 包含了遠端捕捉封包的工具，這樣的好處是可以提供訊框串流，就如同 AP 接
收到的。遠端從 AP 獲取封包可以用來以 AP 優越的位置診斷資料串流的問題，也或許
透過使用分析器在客戶端進行交叉比對。舉例來說，假如連線出現問題，比較從 AP 以
及客戶端附近分析器獲取的封包，也許可以幫助你確定訊框是否在傳輸中遺失。
Wireshark 提供了數種捕捉模式。在無線區域網路的使用，你會需要在監控模式（Monitor
Mode）下捕捉封包，並且呈報所有的訊框在軟體層上。監控模式在捕捉 802.11 的標頭
資訊以及無線電資訊時是必要的，像是資料速率以及
接收訊號強度指示
（
RSSI
）。
網路調校
802.1 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.