TABLE OF CONTENTS This chapter covers the various types of Frames used for data transmission and protocol control under the Fibre Channel Standard protocol. All Frames follow the format shown in Figure 7.1.
There are several different types of Frames, distinguished by the values in the R_CTL, TYPE, and Parameter Header fields. They are broadly classed as either Data or Link Control Frames, with a number of sub-categories for each type:
FC-4 Device Data Frame: Used for transmitting data between N_Ports
Link Control Frames, including the types
Acknowledgment (ACK): Used to acknowledge the successful reception of either one Frame (ACK_1), a set number of Frames N (ACK_N), or all the Frames in a Sequence (ACK_0)
Link Response: Used for indicating Frame-level non-acknowledgment if available, including Fabric and Port Busy (F_BSY and P_BSY) and Reject indications (F_RJT and P_RJT)
Link Command: Only one defined, which is used for resetting the link credit values (LCR)
Basic Link Data: Used for Basic Link Service commands, such as aborting Sequences and abnormally terminating Class 1 Dedicated connections.
Extended Link Data: Used for Extended Link Service commands, such as Port and Fabric Logins and Logouts, aborting Exchanges, requesting transmission status, etc.
Video Data: Used for transmitting data marked as video data, which may be treated differently from other data.
A complete description of the different types of Frames is given in the Frame Header Fields section, on page 112.
