Class 1 Service
This service level guarantees bandwidth and ordering of packets. It also returns confirmations of transmission. 

Class 2 Service 
This service level is connectionless and can deliver packets out-of-order. Delivery of packets is however guaranteed and confirmations are sent. 

Class 3 Service 
This is the lowest service level and does not guarantee either ordering or delivery. 

Fabric Switch
In this category of switch, any port on any switch can provide (subject to bandwidth availability) full speed access to any other port on the network. The network consists of a fabric of linked switches. 

FC-0 
This is the Physical layer of the Fibre Channel protocol stack. This layer includes the definition of all physical components used in Fibre Channel. 

FC-1 
This is the Encode/Decode layer in Fibre Channel specification. It covers the byte encoding and character-level error control. 

FC-2 
This is what is called the Framing Protocol Layer. It incorporates the management of frames, flow control and CRC generation. It also manages sequences of frames comprising a transmission, and exchanges between nodes on the Fibre Channel to accomplish commands akin to the SCSI I/O sequence. This layer also provides the management of the three service classes: Class 1, Class 2, and Class 3. 

FC-3 
This layer is called the Common Services Layer and is currently not used.

FC-4 
This layer is the Protocol Mappings Layer and is the layer that maps protocols such as SCSI and IP to the
underlying layer protocols. 

Fibre Channel Arbitrated Loop (FC/AL) 
This is one of the possible physical topologies of Fibre Channel. In this topology, the Fibre Channel is connected in a loop with devices all connecting to the loop. It can be thought of as a similar structure to a token ring network. Up to 126 nodes can be connected to the loop. 

Fibre Channel Fabric 
This is a structure where addressing of ports on a network of Fibre Channel is made independently of the physical location or address of the target port. Switches are responsible for passing Fibre Channel packets to the target port regardless of which Fibre Channel loop or switch the port physically resides on. Multiple switches can be connected to create large networks with up to 224 addressable ports. 

Fibre Channel Point-to-Point 
This topology for Fibre Channel provides a simple direct connection between just two nodes. This is the closest approximation to the traditional SCSI topology. 

Fibre Channel Topology 
A number of possible topologies exist for the connection of Fibre Channel. One is point-to-point, where a direction connection is made between nodes on the Fibre Channel. Another is Arbitrated Loop where multiple nodes can be connected together. Lastly there is a Fibre Channel Fabric topology which allows for multiple loops and point-to-point connections to be combined into networks using switches. 

Hub
This is a simple connectivity device that allows for devices to be connected to a fibre channel loop by being attached to a hub port. The advantage of this is that failures of a single device on the loop can be isolated from the other ports on the loop. The aggregate bandwidth of the hub is still that of a single fibre channel loop. 

Managed Hub 
This is a technique for providing statistics information about the traffic on a hub. No actual management of the hub is usually possible using this interface, but information and notification of failures can be achieved. This interface often uses Simple Network Management Protocol (SNMP) Management Information Bases (MIBs) as a standard protocol for providing this information. 

Network Attached Storage (NAS) 
This is the provision of storage in a form that is readily accessible on a network. Traditionally this meant having a storage array device that incorporated a file system and presented either a networked file system protocol such as NFS, or else emulated a disk device so that the array could be connected to a storage I/O interconnect to the host. 

Ports
Fibre Channel ports come in a number of flavours depending on the topology of the Fibre Channel. N_Ports are simple equipment node ports in a point-to-point connection topology. NL_Ports are node ports connected to an Arbitrated loop. F_Ports are point-to-point ports connected to a fabric. Generally this means that the F_Port is a port on a switch. FL_Ports are ports connecting from one loop to a switch and thus to a fabric. E_Ports are expansion ports used to interconnect switches together. G_Ports are classified by some switch
companies as ports that can be either E_Ports or F_Ports depending on usage.

Simple Network Management Protocol (SNMP) 
A standard protocol that runs over an IP link to provide management of network type devices without performing continual polling. 

Storage Area Network (SAN)
Simply put, this is the evolutionary step of connectivity provided by Fibre Channel between host and storage. This connectivity provides a true network of storage devices and the hosts that access the storage. 

Zoning 
This is the term used by some switch companies to denote the division of a SAN into sub nets that provide different levels of connectivity or addressability between specific hosts and devices on the network. In effect routing tables are used to control access of hosts to devices. This zoning can be performed by cooperative consent of the hosts or can be enforced at the switch level. In the former case, hosts are responsible for communicating with the switch to determine if they have the right to access a device.