What is fibre channel fabric

Explore, discover, share, and meet other like-minded industry members. Get ahead, stay ahead, and create industry curves. Become a SNIA member today! Skip to main content. Advancing Storage and Information Technology. What is Fibre Channel? White Papers. You are here Home » Education » What Is? Advancing Storage and Information Technology Explore, discover, share, and meet other like-minded industry members. Join SNIA. NPIV makes each virtual link look like a dedicated point-to-point link.

In this way, multiple FC devices and multiple applications or virtual machines VMs on a single FC device can connect to an FC switch using one physical port instead of using a physical port for each connection.

The virtual link creates a secure boundary between traffic from different sources on a single physical connection. NPIV works by creating a unique virtual port identifier for each logical connection on a physical port.

Conceptually, this is similar to splitting a single physical interface into multiple logical interfaces or subinterfaces. This creates a virtual host bus adapter HBA for each virtual link that uniquely identifies the link to the FC switch. The gateway does not provide FC services directly. Policy server—Distributes the rules for administering, managing, and controlling access to FC fabric resources.

Networks can handle a more extensive range of tasks than channels as they operate in an environment of unanticipated connections, while channels operate amongst only a few devices with predefined addresses. Although it is called Fibre Channel, it's architecture doesn't represent neither a channel nor a real network topology. It allows for an active intelligent interconnection scheme, called a Fabric, to connect devices.

All a Fibre channel port has to do is to manage a simple point-to-point connection between itself and the Fabric. The Fibre Channel standard addresses the need for very fast transfers of large amounts of information. FC provides control and complete error checking over the link [2] [3]. In Fibre Channel terms the switch connecting the devices is called Fabric. The link is the two unidirectional fibres transmitting to opposite directions with their associated transmitter and receiver. Each fibre is attached to a transmitter of a port at one end and a receiver of another port at the other end.

Since Fibre channel system relies on ports logging in with each other and the Fabric, it is irrelevant whether the Fabric is a circuit switch, an active hub or a loop.

The topology can be selected depending on system performance requirements or packaging options. Possible FC topologies include point-to-point, crosspoint switched or arbitrated loop Figure 1. Transmission distances vary depending on the combination of speed and media. FC is structured as a set of hierarchical functions Figure 2. The lowest level FC-0 defines the physical link in the system, including the fibre, connectors, optical and electrical parameters for a variety of data rates.

Figure 3 shows the schematic of the Fibre Channel optical link [2]. The system bit error rate BER at the supported media and speeds is less than 10exp [1]. The physical level is designed for the use of large number of technologies to meet the widest range of system requirements.

An end-to-end communicating route may consist of different link technologies to achieve the maximal performance and price efficiency. The FC-0 specifies a safety system - the Open Fibre Control system OFC - for SW laser data links, since the optical power levels exceed the limits defined by the laser safety standards. If an open fibre condition occurs in the link, the receiver of the Port the fibre is connected detects it and pulses its laser at a low duty cycle that meets the safety requirements.

The receiver of the other port at the other end of the fibre detects this pulsing signal and also pulses it's transmitter at a low duty cycle. When the open fibre path is restored both ports receive the pulsing signals, and after a double handshaking procedure the connection is automatically restored within a few seconds [1].

FC-1 defines the transmission protocol including serial encoding and decoding rules, special characters and error control. The information transmitted over a fibre is encoded 8 bits at a time into a 10 bit Transmission Character. The primary rationale for use of a transmission code is to improve the transmission characteristic of information across a fibre. The transmission code must be DC balanced to support the electrical requirements of the receiving units.

The Transmission Characters ensure, that short run lengths and enough transitions are present in the serial bit stream to make clock recovery possible [1] [2]. This information is encoded by FC-1 into the bits a,b,c,d,e,i,f,g,h,j of a bit Transmission Character. The control variable has either the value D D-type for Data characters or the value K K-type for special characters.

Each valid Transmission Character has been given a name using the following convention: Zxx. The information received is recovered 10 bits at a time and those Transmission Characters used for data D-type are decoded into the one of the 8-bit combinations. Some of the remaining Transmission Characters K-type referred to as special characters, are used for protocol management functions.