Computer Network Articles - Page 105 of 122

Gigabit Ethernet can be deployed using both copper wires and fiber optic cables. Since they target to achieve data rates of 1 gigabit per second (1 Gbps), they require encoding – decoding a bit within a nanosecond. This was achieved first in the 1000BASE-CX version.Cabling in Common Varieties of Gigabit EthernetThe popular varieties of fast Ethernet are 1000Base-SX, 1000Base-LX, 1000BASE-T and 1000Base-CX.Cabling in 1000BASE-TUses four pairs of unshielded twisted pair (UTP) cablesGenerally uses Category 5/5e UTP, but can also use Category 6 and Category 7Maximum segment length is 100 metersCabling in 1000BASE-CXUses shielded twisted-pair cables (STP) with DE-9 or 8P8C ... Read More

Frame bursting is a transmission technique used at the data link layer of the OSI model to increase the rate of transmission of data frames. It can be effectively deployed in Gigabit Ethernets to increase network throughput. It is specified in the draft 802.11e QoS specification.By this technique, a sender can transmit a series of frames in succession, without surrendering control on the transmission medium. A set of smaller frames may be concatenated to form a large frame that is transmitted at one go.TechniqueFirstly, we consider a situation without frame bursting −Suppose that a station needs to send three short ... Read More

A multistation access unit (MSAU), also called a media access unit (MAU), is a central device that acts as Ethernet transceivers in local area networks. It is used to connect network stations or nodes in LANs and operates according to the principle of token ring. The multiple stations are connected in a star topology physically but are internally wired into a logical ring.The following figure shows a MSAU having 8 ports shown in black squares and numbered from 1 to 8, each of which can be connected to a device. Additionally, it has two ports ring-out (RO) and ring-in (RI) ... Read More

In computer networks, Gigabit Ethernet (GbE) is the family of Ethernet technologies that achieve theoretical data rates of 1 gigabit per second (1 Gbps). It was introduced in 1999 and was defined by the IEEE 802.3ab standard.Varieties of Gigabit EthernetThe popular varieties of fast Ethernet are 1000Base-SX, 1000Base-LX, 1000BASE-T and 1000Base-CX.1000BASE-CXDefined by IEEE 802.3z standardThe initial standard for Gigabit EthernetUses shielded twisted pair cables with DE-9 or 8P8C connectorMaximum segment length is 25 metresUses NRZ line encoding and 8B/6B block encoding1000BASE-SXDefined by IEEE 802.3z standardUses a pair of fibre optic cables of a shorter wavelength having 770 – 860 nm ... Read More

Throughput of a system refers to the rate of processing of a task thereby generating results. Ethernet is a set of technologies primarily used in LANs, whose primary data units are frames. The throughput of Ethernet is measured by the rate of successful delivery of frames over a communication channel.There are several methods for representing Ethernet throughput. The least ambiguous among them is calculation of channel efficiency. Channel efficiency, is the percentage of the net bit rate (in bits per second) of a channel that is actually communicated. Suppose that an Ethernet connection has a speed of 100 Mbps. But, ... Read More

Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is a network protocol for carrier transmission that operates in the Medium Access Control (MAC) layer. It senses or listens whether the shared channel for transmission is busy or not, and defers transmissions until the channel is free.When more than one stations send their frames simultaneously, collision occurs. Back-off algorithm is a collision resolution mechanism which is commonly used to schedule retransmissions after collisions in Ethernet. The waiting time that a station waits before attempting retransmission of the frame is called as back off time.Algorithm of CSMA/CDStep 1) When a frame is ... Read More

100BASE-T4 is the early implementation of Fast Ethernet over twisted pair cables, carrying data traffic at 100 Mbps (Mega bits per second) in local area networks (LAN). It was launched as the IEEE 802.3u standard in 1995. Here, 100 is the maximum throughput, i.e. 100 Mbps, BASE denoted use of baseband transmission, and T4 denotes use of four twisted pair cables in Fast Ethernet.PropertiesThis has four pairs of unshielded twisted pair of Category 3. i.e. voice grade.Two of these pairs are bi-directional and the other two are unidirectional. The two unidirectional wires are reserved for receiving and sending data respectively. ... Read More

100BASE-FX is the technical name of Fast Ethernet over fiber optic cables. It is a version of Fast Ethernet carrying data traffic at 100 Mbps (Mega bits per second) in local area networks (LAN). It was launched as the IEEE 802.3u standard in 1995. Here, 100 is the maximum throughput, i.e. 100 Mbps, BASE denoted use of baseband transmission, and FX denotes use of optical fibers in Fast Ethernet.The 100BASE-FX Physical Medium Dependent (PMD) sublayer is defined by Fiber Distributed Data Interface (FDDI).PropertiesThis has two pairs of optical fibers. One pair transmits frames from hub to the device and the ... Read More

100BASE-TX is the technical name of Fast Ethernet over twisted pair cables. It is a predominant form of Fast Ethernet carrying data traffic at 100 Mbps (Mega bits per second) in local area networks (LAN). It was launched as the IEEE 802.3u standard in 1995. Here, 100 is the maximum throughput, i.e. 100 Mbps, BASE denoted use of baseband transmission, and TX denotes use of twisted pair cables in Fast Ethernet.PropertiesThis has either two pairs of unshielded twisted pairs (UTP) category 5 wires or two shielded twisted pairs (STP) type 1 wires.One of these pairs transmits frames from hub to ... Read More

In computer networks, Fast Ethernet is a variation of Ethernet standards that carry data traffic at 100 Mbps (Mega bits per second) in local area networks (LAN). It was launched as the IEEE 802.3u standard in 1995, and stayed the fastest network till the introduction of Gigabit Ethernet.Fast Ethernet is popularly named as 100-BASE-X. Here, 100 is the maximum throughput, i.e. 100 Mbps, BASE denoted use of baseband transmission, and X is the type of medium used, which is TX or FX.Varieties of Fast EthernetThe common varieties of fast Ethernet are 100-Base-TX, 100-BASE-FX and 100-Base-T4.100-Base-T4This has four pairs of UTP ... Read More