Chapter 2 - 15. Understanding Congestion in Fibre Channel Fabrics

Fibre Channel Frame Format

The size of a Fibre Channel frame can be up to 2,148 bytes carrying up to 2,112 bytes of payload or data, as shown in Figure 2-25. 如图 2-25 所示，光纤通道帧的大小可达 2,148 字节，最多可携带 2,112 字节的有效载荷或数据。

Figure 2-25 Fibre Channel frame format

A Fibre Channel frame is composed of the following: 光纤通道帧由以下部分组成：

 A Start-of-Frame (SOF) delimiter (4 bytes): SOF is a type of ordered set (bit sequence with special function) that immediately precedes the frame content and follows fill words. It conveys the beginning of a frame. 帧开始（SOF）定界符（4 个字节）： SOF 是一种有序集合（具有特殊功能的位序列），紧接在帧内容之前，填充字之后。它表示帧的开始。

 An End-of-Frame (EOF) delimiter (4 bytes): EOF is a type of ordered set that immediately follows the frame content and is followed by fill words. It conveys the end of a frame. 帧末定界符（EOF）（4 个字节）： EOF 是一种有序集，紧跟在帧内容之后，后面是填充字。它表示帧的结束。

 Frame content is composed of the following: 框架内容由以下部分组成：

 Zero or more Extended headers: Extended headers extend the functionality of the frame header, such as the Cisco Virtual SAN (VSAN) technology. 零个或多个扩展报头： 扩展报头可扩展帧报头的功能，如 Cisco Virtual SAN (VSAN) 技术。

 Frame header (24 bytes): T