Fibre Channel Networking Model
It is easier to understand a communications protocol if it is first broken down into parts or layers.
For better understanding, the Fibre channel protocol has been broken into five layers.
The FC-0 and FC-1 layers specify physical and data link functions needed to physically send data from one port to another.
FC-0 Layer (Physical Layer)
FC -0 specifications include information about feeds and speeds.
It is the lowest layer, and defines the physical connectivity in the system like cabling, connectors, and electrical parameters for the system at a wide range of data rates.
FC-1 layer (Encoding & decoding)
The second layer, FC-1 deals with encoding and decoding
Fibre channel uses two types of encoding and decoding techniques 8B/10B and 64b/66b.
FC-2 Layer (Framing & Flow control)
It specifies the content and structure of information along with how to control and manage information delivery. This layer contains basic rules needed for sending data across the network. This includes:
(1) How to divide the data into frames,
(2) How much data should be sent at one time before sending more (flow control), and
(3) Where the frame should go.
It also includes Classes of Services, which define different implementations that can be selected depending on the application.
FC-3 Layer (Common services)
It defines advanced features such as striping (to transmit one data unit across multiple links) and multicast (to transmit a single transmission to multiple destinations) and hunt group (mapping multiple ports to a single node). So, while the FC-2 level concerns itself with the definition of functions with a single port, the FC-3 level deals with functions that span multiple ports.
FC-4 Layer (Upper protocol mapping)
It provides a mapping of Fibre Channel capabilities to pre-existing protocols, such as IP or SCSI, ATM, etc.
