电信通讯

IEEE 802.1Qbb-D2.2 和802.3bd-D2.0动态

2010年05月7日

由朱文昊 Albert Zhu发表在标准化

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本文是专题：IEEE标准动态中的第2篇，共4篇

在2010年5月22日前，IEEE 802.1Qbb-D2.2 和802.3bd-D2.0将完成投票。

这两个文档都是关于在802点到点全双工DCB网络中增加基于优先级的流控功能的最新标准。

在802.3bd中主要变化是向MACCControlEntity里增加了aPFCEnableStaus。

802.1Qbb变化就比较多了。基于优先级流控，即Priority-based Flow Control ，简称PFC。

增加对下列标准的引用：

IEEE Std 802.1AE: Media Access Control (MAC) Security
IEEE Std 802.1Qaz: Enhanced Transmission Selection for Bandwidth Sharing Between Traffic Classes
IEEE Std 802.3bd: MAC Control Frame for Priority-based Flow Control

增加了下列定义

3.1 bit time: The duration of one bit as transferred to and from the Media Access Control (MAC). The bit time is the reciprocal of the bit rate.
3.2 Paused state: A state of a queue in which the transmission selection entity does not select frames from the queue.
3.3 Data center environment: A domain controlled by the Data Center Bridging eXchange protocol (DCBX, see IEEE Std 802.1Qaz clause 38).

增加了缩略语定义

DCBX   Data Center Bridging eXchange protocol
PFC      Priority-based Flow Control
TLV     Type, Length, Value

其他很多详细变化就不一一列举，请下载最新版相关协议阅读。（注意MIB也有变化）

朱文昊点评：在增加了基于优先级流控的系统中，可以提高关键业务的QoS，改善用户体验，不论对大型应用还是家庭应用，都将会带来很多好处。

关于IEEE802族协议文本的下载.

2010年03月9日

由朱文昊 Albert Zhu发表在学术交流

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今天拿到我的博客访问记录里，有一位朋友在百度里搜索IEEE802.15.4的协议文本下载，并且来到了我的博客。我饶有兴致的看了看怎么回事。原来百度里一堆不想关的页面列在首页，我的博客也忝列其中。

看来还是有人不知道在哪里下载IEEE的802族协议文本。IEEE802协议族，由于广泛流行，长了IEEE标准化协会的很大面子。所以IEEE802族协议，是可以在其官方网站上免费下载的。网址是

http://standards.ieee.org/getieee802/

或许朋友们可以在若干个协议文本里搜索到我的名字哦 Wenhao Zhu，呵呵。比如在 802.15.4c协议里。

由于相关许可协议限制，我不能把该协议文本贴在我的博客上，我也建议您不要做。以下是许可协议摘录

COPYRIGHT

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不仅IEEE的这类标准可以下载，ITU的几乎所有标准都可以很容易的从官网上下载到相关文件。

最后建议一下，搜索这些东西，尽量用英语关键词，尽量用Google.com