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.
鏈結層的基礎
|
59
屬性 A-MPDU A-MSDU
傳輸可靠性和抗干擾性 較高，每個子訊框有自己的 FCS 可
以獨立檢查。一個子訊框的遺失僅
會造成聚合中的單一元件損失。
較低，如果 FCS 檢查失敗，所有子
訊框都會被丟棄。
訊框加密 應用於個別的子訊框，每個子訊框
必須個別進行解密。
應用於整個聚合，僅需要一次解
密，就可以取得所有子訊框。
QoS 流量等級 多重，每個子訊框一種流量等級。 所有子訊框一種流量等級。
接收支援需求 是，並且經過 Wi-Fi 聯盟認證測試。 是，並且經過 Wi-Fi 聯盟認證測試。
傳輸支援需求 否， 在 802.11n 和 Wi-Fi 聯盟認證
中為選用。
否，不需經過 Wi-Fi 聯盟認證測試。
區塊回應（Block Acknowledgment）
802.11 的 MAC 如同最初在 1997 年所規範的那樣，每個訊框都需要一個正面回應
（Positive Acknowledgment）。每個傳輸在尚未收到一個回應前，都不是完整的。網路
流量通常都是突發性的。例如，一個使用者在閱覽網頁時將會先送出一個請求，接著
會接收到一連串夾帶著請求的網頁之封包，而當使用者閱讀網頁時，網路通常是閒置
的。802.11 MAC 原始的構想為每個送到接收器的訊框都需要得到個別的回應，如圖 5-7
（a）所示。在 802.11e 的服務品質（Quality-of-Service）擴充中引進了
區塊回應
（
Block
Acknowledgment
，通常簡稱為 BlockACK），它可以允許發送端傳送一道訊框串流，並且 ...
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.