What is Fibre Channel Protocol?

A storage area network (SAN) essentially operates like an external hard drive, except that the external hard drive is tightly controlled, attached to a network, and can be used by multiple devices. Of course, that’s a gross oversimplification, but that begs the question of how do you attach the storage drives in a SAN to computers across the network? 

One of the ways you can do that is through the Fibre Channel Protocol. Today we will discuss what the Fibre Channel Protocol is and how it works. 

An Overview of Fibre Channel Protocol

In this video, CBT Nuggets trainer Jeff Kish introduces the Fibre Channel Protocol, how Fibre Channel is different from ethernet, and what equipment you need to make Fibre Channel work.

What is Fibre Channel Protocol?

Fibre Channel Protocol is a very specific thing meant strictly for storage. More specifically, the Fibre Channel Protocol only supports SCSI messaging. SCSI is an interface used to connect and communicate with storage drives in a computer. You’ll likely only find SCSI drives in a server, but they can be found in high-performance machines as well. 

Fibre Channel Protocol uses fiber optic media to transport SCSI messages over the network. It’s a high-speed, network-attached SCSI protocol. 

There’s a difference between Fibre Channel Protocol and your traditional ethernet-based network. Actually, there are a few differences. For instance, Fibre Channel Protocol doesn’t use ethernet, IP, TCP, or UDP connection. Frames (or packets) aren’t sent through ethernet either. 

Fibre Channel Protocol has its own stack. Frames are a little different than your traditional ethernet frame, too. The header in a Fibre Channel Protocol frame is 24 bytes in size. There’s an additional optional header space that's 64 bytes in size as well. Finally, the payload portion of the frame weighs in at 2048 bytes. On some occasions, the additional header space and payload portions of the frame are combined. 

Before jumping to the next section, we need to mention FCoE or Fibre Channel over Ethernet. FCoE facilitates sending Fibre Channel frames through an ethernet network by encapsulating Fibre Channel frames inside an ethernet frame. There are various pros and cons to using FCoE, but that is beyond the scope of this article. 

Does Fibre Channel work with regular switches?

Fibre Channel Protocol is not compatible with standard networking equipment. That makes sense, right? Fibre Chanel Protocol does not use ethernet, IP, TCP, or UDP. So, standard network equipment doesn’t have the bits required to process communications for Fibre Channel. 

Instead, networks use specific equipment made for Fibre Channel. For instance, Cisco has a line of products called MDS switches. These switches still operate using the NX-OS. Many of the same commands traditionally used in a standard switch are also used to manage MDS switches. These switches use the Fibre Channel protocol for communication. 

Nodes, or the storage servers, don’t use standard network interface adapters either. Instead, they use a host bus adapter. It looks similar to a fiber-optic network card but uses the Fibre Channel Protocol instead. 

You might be familiar with MAC addresses.  If not, a MAC address is an identifier specific to each electronic device that communicates via a network somehow. Routers, switches, and even your smartphone have MAC addresses. They are vital for an ethernet-based network to operate. 

Fibre Channel networks do not use MAC addresses.  They do have a similar identifier, however. Actually, there are two. One is called the WWNN or worldwide node name.  The other is WWPN or worldwide port name. Both are burned into devices and cannot be changed. They work in a similar way to a MAC address. 

One last thing we need to mention. Like all things with computers, Fibre Channel Protocol typically operates on the powers of two. For instance, the protocol started with 1Gb transfer speeds. Then it moved to 2Gb. Then 4Gb. Today we have Fibre Channel speeds as fast as 64Gbs, and soon 128Gbs will be deployed in the wild, too. 

Learn More About Fibre Channel with CBT Nuggets

The Fibre Channel Protocol is a godsend in today’s modern enterprise network. Fibre Channel gives IT admins a way to facilitate large amounts of storage in a controlled manner. Learning Fibre Channel is essential for any hopeful network or sysadmin. 

If you want to upgrade your IT career consider earning the CCNP.  The CCNP is a hallmark of the IT career, and CBT Nuggets has an online training course for CCNP prep.