Class 2 is ideal for data transfers to and from a shared mass-storage system physically located at some distance from several individual workstations. CLASS 3 This CoS is a connectionless service that allows data to be sent rapidly to multiple devices attached to the fabric, but no confirmation of receipt is given. It is most practical when it takes a long time to make a connection.
By not providing confirmation, the one-to-many Class 3 service speeds the time of transmission. Class 3 service is very useful for real-time broadcasts, such as weather visualizations, where timeliness is key and information not received has little value after the fact.
Fibre Channel also provides an optional mode called Intermix, which reserves the full Fibre Channel bandwidth for a dedicated Class 1 connection, but also allows connectionless traffic to share the link if there is available bandwidth. Topologies As noted , Fibre Channel supports multiple interoperable topologies—including point-to-point, arbitrated-loop, and switched.
The simplest topology is point-to-point, where two nodes are connected together directly. In the arbitrated loop, any number of nodes may be connected together, but only nodes may be active at any one time due to addressing limitations. Multiple loops can be connected together in a switched topology to greatly extend the addressing range, or to reduce the bandwidth limitations of a single shared loop. Figure 47 Fibre Channel meets the connectivity needs of diverse distributed computing environments through the use of hubs and switches.
Switches furnish the backbone for all connected devices, with one or more switches providing the switching fabric. The switch fabric allows the attachment of thousands of nodes. The devices can be attached directly to Fibre Channel switches or to hubs that in turn connect to the switches Figure 47 , depending on the application.
Accessing the services available from the switching fabric requires a network interface card NIC for each node, which enables it to connect to the fabric, as well as to the operating system and the applications. This configuration knowledge is important to the performance levels of channels. Fibre channel supports a transmission speed of 1, 2, 4, 8, 16, 32, and Gbps.
While, the speed of optical transceiver used in Ethernet ranges from Fast Ethernet of up to Mbps, Gigabit Ethernet of up to Mbps, 10 Gigabit of up to 10 Gbps to even some 40 or Gbps today. The former is more popular in big enterprise network while the latter is commonly used in small-to-medium businesses.
From all the above, Fibre Channel and Ethernet are two different technologies used in telecommunications. It was released in by the T11 Committee. Its throughput is MBps. Although, 16G FC was released in , but it gained in popularity recently. Now a days, 16G fibre channel comes as a standard option in almost all of the latest SAN storages and servers. After the release of 10G fibre channel, the industry decided to change the naming convention of fibre channel versions.
With the release of 16G FC, it was decided to discard the speed-based naming and adopt generation-based naming. The first four versions being the 1G, 2G, 4G and 8G fibre channels. Both of these versions were released in The sixth generation of fibre channel provides incredible increase in the throughputs. Generally speaking, 8GFC networks run close to the effective rate of 10GbE, so the difference is nearly negligible.
In a word, the practical transmission speed of each will be decided by the specific working environment. In most cases, Ethernet switches are much cheaper than Fibre Channel switches. However, Fibre Channel is mainly used in the data center SAN environment, while Ethernet can be found in different kinds of networks: from small homes, big offices to large-scale data centers. When it comes to enterprises, many already have invested large amounts of time and effort for their Fibre Channel networks, switching to Ethernet means a start-over with extra expenses.
Thus Ethernet isn't always a price-wise option. Besides, the maintenance fee is also a factor that should be considered. In large IT systems, if an Ethernet switch breaks down, most admins can deal with it. However, when there is something wrong with the Fibre Channel switches, they need to turn to manufacturers, instead. Many Ethernet proponents may argue that Fibre Channel is dying on account of Ethernet's high-performance, simplicity, and popularity in most applications.
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