FibreChannelFibre Channel is a technology which is used for transferringdata at a high speed ranging in between 4 GBPs to 10 GBPs and is primarily used to connect computer datastorage to servers. Fibre channel is mainly used in storagearea networks in commercial data centers. Fibre Channel runs on opticalfiber cables between data centers and can also run on copper cabling. FibreChannel supports many upper level protocols.
Fibre Channel Protocol is atransport protocol that predominantly transports commands over fibre channelnetworks. Fibre Channel can be used to transport data from storage systems thatuse solid state flash memory storage medium.Fibre channel uses a protocol known as Fibre channel protocol(FCP).This communication medium is equal to that of transmission control protocol orthe TCP IP. It is predominantly used to transport the small computer system interfacecommands on a framework of fibre channel network.
Fibre channel protocol is highlyuseful in the storage networking field and is according to the Inter NationalCommittee for Information Technology standards. This protocol was formerly inventedfor transferring high speed data in order to assist the super computers. Butslowly and steadily it is now being used as a data transfer standard in the fiberchannel field. The truth is that the fibre channel protocol can be carried outon a twisted pair copper wire along with the fibre optic cables.
Fibre ChannelProtocol is almost three times fast and has now become the interface in betweenthe collection of storage devices and their servers. It is flexible to transmitdata within 10 km radius. It is acting as a physical medium but transferringdata on an optical fibre makes it too expensive. However, the fibre technologyis also useful with twisted pair of telephone lines and coaxial cables and thusmakes the budget factor become a less hindering criterion.FibreChannel TopologiesFibre channeltopologies describe the way the ports are connected together. In a fibre channeltechnology, a port is an entity which participates in communication over thenetwork and it does not be a hardware related port.
Fibre channel ports areemployed in disk storages. The fibre channel protocol topologies are asfollows: · Point to Point TopologyIn this fibrechannel topology, two devices are connected directly to each other and havecertain connectivity limitations. Figure: Point to Point Topology· Arbitrated Loop TopologyIn thistopology, the devices are linked in a ring or a loop and the concept of tokenring networking is employed. However, a new addition or subtraction of the loopwill get interruption and can cause a failure due to a single device disruption.A fibre channel hub is useful to by-pass the failed ports and the loop will behelpful in cabling each port to the next port in the ring.
This allows only onepair of ports communicating with each other and the speed which can be reachedis only 8 GB on the fibre channel.Figure: Arbitrated Loop Topology · Switched FabricThis topologyof fibre channel works similar to that of Ethernet architecture and lets outthe duty of optimized inter linkage to the switches and makes the data flowrestricted to only two ports. In the event of a failure of a port, the effectis neutralized. In addition to this multiple ports communication is alsopossible on a fabric. Figure: Switched Fabric TopologyFibreChannel Layers Fibre channeldoes not abide by the OSI model or the Open System Interconnection layering andfollows its own five layers: · FC- 0:Layer 0 is aphysical link which is involved in the computing and can also encompass fibreconnectors with certain electrical and optical parameters.
· FC- 1:This fibrechannel layer will allow a transmission protocol, which will encompass specialcharacters, encodes and decodes the rules and sustains error control. Thetechnology of fibre makes the 8-bit encoding go up the 10-bit transmission at atime. This transmission code is balanced with a direct current, in order to goalong with the electrical basis of the units which are at the receiving end ofthe data.· FC- 2:Thistransmission protocol offers structuring of data transmission in between twoports and the different mechanisms for refining the classes for service andmanages the data transfer sequence.· FC- 3:This Fibre channellayer includes multicasting, stripping and hunt group in it. · FC- 4:This layeracts as an interface of upper layer protocol and is having specific mapping protocols,which offer FC-PH (physical layers) and ULPs.
Table 1.1: FibreChannel Protocol StackFibreChannel BenefitsFibre channel offers high performingdata transmission for the data storage solutions and is opted for video storagenetworks. This technology offers solution for network based storage and datawarehouses.
· Comparisonof Price and PerformanceAlthough this technologyis expensive but considering its performance levels, it will justify its pricewith an unrivalled reliability and availability. · SupportFibre channel works on par with theSCSI, Internet Protocol, ESCON, VI and AV technologies and the performancelevels will never get compromised.· Congestion freeThe fibre channel technology isspecially formulated to reduce the data flow congestion and is said to bebetter suited for Block Level Storage.· Efficiency Theperformance levels are excellent and the efficiency factor is also excellent forthe storage area networking. · ScalableSince the scalability factor issatisfied to the peak by the fibre channel, there is no swivel in theperformance standards as well.