FCP (Fibre Channel Protocol)

Protocol means a set of instructions or rules and regulations. So, instead of first learning about fiber channel protocol, let’s get into what a fiber channel is:

Fibre Channel is a high-speed networking technology primarily used for transmitting data among data centers, computer servers, switches, and storage at data rates of up to 128 Gbps with distances up to 10Km. 

Fibre Channel Protocol (FCP) is the SCSI (Small Computer System Interface) interface protocol operating on an established Fibre Channel connection. As Fibre Channel provides us with a high-speed data transfer service it can be used to connect workstations, mainframes, displays, storage devices, and supercomputers. The FCP provides one standardized way for storage, data transfer, and networking as the main task of the FCP is to ensure the successful transfer of large and bulky information/ data so that the manufacturers can easily support a variety of channels and networks.  

The Fibre Channel protocol, also known as FC, is a method for transferring data serially over copper or optical fiber in order to achieve lower latency and faster speeds. It is a SCSI interface protocol that utilizes Fibre Channel connections. This protocol is used to connect high-performance computers, storage devices, mainframes, big data workstations, and displays as virtual big data structured screens.

So, Fibre Channel is primarily used to connect computer data storage to servers in storage area networks (SAN) in commercial data centers. Though fiber channel mainly runs on optical fiber cables it is also capable of transmitting over copper cables. As mentioned earlier, fiber channels can transmit data up to 128 Gbps (Gigabits per second) hence the alternate name Gigabit Fibre Channel (GFC).

FCP Topologies:

• DAS (Direct Attached Storage)
• NAS (Network Attached Storage)
• SAN (Storage Area Network)

FCP Ports:

• N Port (The Node Port)
• F Port (The Fabric Port)
• L Port (The Loop Port)
• FL Port (The Fabric Loop Port)
• E Port (The Extension Port)
• G Port (The Generic Port)
• GL Port (The Generic Loop Port)
• SL Port (The Segmented Loop Port)
• TL Port (The Translated Loop Port)
• T Port (The Trunk Port)

There are two main protocols for fiber channels with regard to block storage:

1. Fibre channel protocol (FCP): covered in the article 
2. FICon (Fibre Connection) is a protocol that transports ESCon (Enterprise Systems Connection)  commands, used by IBM mainframe computers, over Fibre Channel.

FCP Features Fibre Channel:

• Data transfer speed of up to 128Gbps over a distance of 10Km.
• Both Fiber optic cable and copper cables can be used.
• FCP is used to transmit SCSI (Small Computer System Interface) commands over a Fibre Channel Network (FCN)
• The Fibre Channel Protocol (FCP) is an original protocol used in Storage Area Network (SAN).
• SFP (Small Form-factor Pluggable) connectors are used to facilitate a reliable, wired, high-speed connection.
• The Fibre Channel Protocol (FCP) offers a bandwidth range of 100 MB/s to 1.6 GB/s and can support distances of up to 500 meters to 10 kilometers.
• FCP operates similarly to both TCP and UDP protocols.
• The Fibre Channel Protocol (FCP) is both reliable and stable, with a balanced design.
• In Fibre Channel Protocol (FCP), World Wide Names (WWN) are used for addressing. 
• These 8-byte addresses consist of 16 hexadecimal characters.
• The Fibre Channel Protocol (FCP) uses a format such as 15:00:00:f0:8c:95:de.
• Ability to carry multiple existing interface command sets, including Internet Protocol (IP), SCSI, IPI, HIPPI-FP, and audio/video.
• Support for multiple cost/performance levels, from small systems to supercomputers.
• In Fibre Channel Protocol (FCP), a dedicated host bus adapter, specialized cables, and switches are used. It is distinct from Ethernet at all layers of the OSI model, including the physical layer

World Wide Name (WWN):

A World Wide Name (WWN) or World Wide Identifier (WWID) is a unique identifier used in storage technologies like Fibre Channel. It is a unique identifier that is hard-coded into each Fibre similar to how devices have MAC Addresses. It is a 64-bit or 128-bit name and is assigned by the Institute of Electrical and Electronics Engineers IEEE. Each network storage device that a manufacturer produces must include the manufacturer’s WWN, in order to help system administrators (SA) uniquely categorize and identify storage segments.

The WWN looks for example:

15:00:00:f0:8c:08:95:de

Types of World Wide Name (WWN):

There are majorly two types of WWNs implemented in an FC Storage Area Network (SAN): 

1. World Wide Node Name (WWNN): A World Wide Node Name, WWNN, or WWnN, is a World Wide Name assigned to a node (an endpoint, a device) in a Fibre Channel fabric.
2. World Wide Port Name (WWPN): a World Wide Port Name, WWPN, or WWpN, is a World Wide Name assigned to a port in a Fibre Channel fabric. In order to behave as a unique identifier in the network, it works similarly to the MAC address in Ethernet protocol.

Fibre Channel Protocol (FCP) uses World Wide Node Names (WWNN) to identify nodes in data storage networks. These names can identify multiple network interfaces on a single node. The WWPN (World Wide Port Name) can also be derived from the WWNN.

• In Fibre Channel Protocol (FCP), a unique World Wide Port Name (WWPN) is assigned to every individual port on a node.
• In Fibre Channel Protocol (FCP), a multiport Host Bus Adapter (HBA) will have a different number of World Wide Port Names (WWPNs) for each port. WWPNs are similar to the MAC address in Ethernet networks.
• In Fibre Channel Protocol (FCP), World Wide Port Names (WWPN) are burn-in by the manufacturer. They are validated to be globally unique.
• In Fibre Channel Protocol (FCP), World Wide Port Names (WWPNs) are assigned to Host Bus Adapters (HBAs) on both client and storage systems.
• In Fibre Channel Protocol (FCP), World Wide Port Names (WWPNs) are given more importance when configuring Fibre Channel Networks, compared to World Wide Node Names (WWNNs).
• In Fibre Channel Protocol (FCP), World Wide Port Names (WWPNs) cannot be changed once assigned.

Advantages of Fibre Channel:

• FCP has high performance
• provides good backup and restoration and simplified consolidation
• also offers congestion-free data flow, Gigabit bandwidth, compatibility with multiple topologies and protocols, flow control, and self-management
• It is providing high-speed data transfer
• It is cost-efficient
• High-speed data can be transferred over a distance of 10km
• supports several fault-tolerant features
• FCP having good bandwidth and speed
• The FCP protocol utilizes data frames for transmitting information over a network, which can be used for both link-level and device-level communications
• FCP having good Flow Control
• The Fibre Channel protocol (FCP) is known for its balanced and reliable nature, providing stable communication between devices
• FCP is a balanced and reliable protocol that is used to transmit SCSI (Small Computer System Interface) commands over Fibre Channel Networks (FCN)

Disadvantage of Fibre Channel:

• FCP can be more expensive in cost compared to iSCSI
• FCP can be more costly and complex to implement
• FCP requires updating the cards within servers
• also purchasing FC cables and switches
• More expensive than SCSI (Small Computer System Interface)
• More complex than SCSI (Small Computer System Interface)
• More equipment/ overhead (like FC cables, switches, etc.,) is required