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Networking Basics: Differences between Architectures Authored by David T. Butler | |
| Networking Basics |
Ethernet ARCnet Token Ring Summary
BandwidthThe major difference of these architectures is in bandwidth. Please note that bandwidth is a measure of potential rate that data can be transmitted over a network.There is always a bottleneck somewhere in a communication process. One of the two computers communicating may be slower than the other, have inferior resources compared to the other, or be performing more tasks than the other.
Bandwidth vs. ThroughputThroughput is the actual speed data will transfer at from one point on the network to another. The actual speed, throughput, of a network is often quite less than it's Bandwidth, potential speed.Bandwidth is more often quoted than Throughput since it is easier to calculate and not subject to changes in many variables. The hardware used to communicate, heavy/light traffic, etc…can effect throughput.
EthernetEthernet typically comes in two flavors of bandwidth, 10 mbps and 100 mbps.Recently, Gigabit Ethernet (1000 mbps) has become available and affordable but is still not in widespread use. Gigabit Ethernet can use either copper (CAT6) or fiber cable. Gig-E has had to compete with the OC-3/OC-12/OC-48/OC-192/OC-768 fiber optic lines that already enjoyed a large installed user base when Gig-Ethernet came on the scene. Being a "new" technology, Gig-E has had it's struggles with the still forming standards and compatibility issues between manufacturers. Fortunately, for 10 mbps networks that are upgrading, CAT5/UTP cable is already rated for 100 mbps. Ethernet running on Coax is limited to 10 mbps. ARCnetARCnet is limited to 2.5 Mbps and no longer in wide use. There once was an effort to produce high-speed ARCnet.That effort met little success and it is hard to find a mention of it in ARCnet reference materials. Token RingToken Ring comes in both a 4 mbps and 16 mbps version.The 16 mbps version requires STP, shielded twisted pair, which could easily cost two or three times the price of UTP. The, much older, 4 mbps version would allow the use of UTP - but it was only 4 mbps. The major drawback to running 16 mbps Token Ring over 10 mbps ethernet was the token passing. Each NIC is responsible for passing the token on to the next after its predefined turn is up. If just one card malfunctions and fails to do this, the token could be lost and all the other cards will sit there still waiting for the token. For this reason, Token Ring networks typically have large support staffs. SummaryOverall, running Ethernet in the 10 or 100 mbps flavor on a Star networking topology is the most flexible and reliable choice. However, in any information system, the software should drive the hardware decisions.If a company can not run without software that only works on some old Unix system, they will need hardware and, at least part of, a network that supports that Unix system.
In this scenario, standard workstations can still be deployed using terminal emulation software to connect to the Unix system. The terminal emulation software pretends to be a VT100 or, dumb tube, station previously used to access the custom Unix software.
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