Understanding Ethernet

The term Ethernet refers to the family of Local Area Network (LAN) implementation. Ethernet is actually the most popular Local Area Network architecture that consists of Ethernet specifications and standards as well as Ethernet hardware devices such as Ethernet splitter, Ethernet drivers and USB Ethernet device.

Ethernet specifications include three principal categories:

Ethernet and IEEE 802.3: LAN specification that operate at 10 Mbps over coaxial Ethernet cable.
100-Mbps Ethernet: A single LAN specification, also known as Fast Ethernet that operates at 100 Mbps over twisted pair Ethernet cable.
1000-Mbps Ethernet: A single LAN specification, also known as Gigabit Ethernet that operates at 1000 Mbps (1 Gbps) over fiber and twisted pair Ethernet cables.

Ethernet has survived as an essential media technology because of its tremendous flexibility and its relative simplicity to implement and standard. Although other technologies have been touted as likely replacements, network managers have turned to Ethernet and its derivatives as effective solutions for a range of campus implementation requirements. To resolve Ethernet's limitations, innovators (and standards bodies) have created progressively larger Ethernet pipes. Critics might dismiss Ethernet as a technology that cannot scale, but its underlying transmission scheme continues to be one of the principal means of transporting data for contemporary campus application.

What Is Ethernet?

Ethernet is a baseband LAN specification invented by Xerox corporation operates at 10 Mbps using career sense multiple access collusion detect (CSMA/CD) to run over coaxial cable. Ethernet was created by Xerox in the 1970s, but the term is now often used to refer to all CSMA/CD LANs. Ethernet was designed to serve in network with sporadic, occasionally heavy traffic requirements, and the IEEE 802.3 specification was developed in 1980 based on the original Ethernet technology. Ethernet version 2.0 was jointly developed by Digital Equipment Corporation, Intel Corporation and Xerox Corporation. It is compatible with IEEE 802.3.

Ethernet and IEEE 802.3 are usually implemented in either an interface card on a primary circuit board. Ethernet cabling conventions specify the use of a transceiver to attach a cable to the physical network medium. The transceiver performs many of the physical layer functions, including collusion detection. The transceiver cable connects end stations to a transceiver. Ethernet provides services corresponding to Layer 1 and Layer 2 of the OSI reference model. IEEE 802.3 provides for a verity of cabling options, one of which is a specification referred to as 10Base5. This specification is the closest to Ethernet. The connecting cable is referred to as an Attachment Unit Interface (AUI), and the network attachment device is called a Media Attachment Unit (MAU), instead of a transceiver.

Ethernet Hub Operations

In Ethernet broadcast-based environment, all stations see all frames placed on the network. Following any transmission, each station must examine every frame to determine whether that station is a destination. Frames identified as intended for a given station are passed to a higher-layer protocol. Under the Ethernet CSMA/CD media-access process, any station on a CSMA/CD LAN can access the network at any time. Before sending data, CSMA/CD stations listen for traffic on the network. A station waiting to send data waits until it detects no traffic before it transmits.

As a contention-based environment Ethernet allows any station on the network to transmit when ever the network is quite. Collusion occurs when to stations listen for traffic, hear none, and then transmit simultaneously. In this situation, both transmissions are damaged, and the station must retransmit at some later time. Back-off algorithms determine when the colliding stations should retransmit.

Gigabit Ethernet

Gigabit Ethernet is an extent ion of the IEEE 802.3 Ethernet standard. Gigabit Ethernet builds on the Ethernet protocol but increases speed tenfold over Fast Ethernet, to 1000 Mbps, or 1 Gbps. This MAC and PHY standard is promises to be a dominant player in high-speed LAN backbones and server connectivity. Because Gigabit Ethernet significantly leverages on Ethernet, network managers will be able to leverage their existing knowledge base to manage and maintain Gigabit Ethernet networks.

Migration to Gigabit Ethernet

Several means can be used to deploy Gigabit Ethernet to increase bandwidth and capacity with in the network. First, Gigabit Ethernet can be used to improve Layer 2 performance. Here, the through put of Gigabit Ethernet is used to eliminate Layer 2 bottlenecks.

Scaling Bandwidth with Fast EtherChannel and Gigabit EtherChannel

Bandwidth requirements with in the network core and between the network core and the wiring closet have placed significant demands on the networks. Fast EtherChannel allows multiple fast Ethernet ports to be bundled together and seen logically by the Ethernet switches as a fat pipe. Fast EtherChannel allows the bundling of up to four ports, for an aggregate bandwidth of 800 Mbps. With support from Ethernet card manufacturers such as Sun Microsystems, Intel, SGI, Compaq, and Adaptec, Fast EtherChannel can now be provided directly to high-end file servers.

Scaling Router Backbones

Many large-scale networks use a meshed core of routers to form a redundant network backbone. This backbone typically consists of FDDI, ATM or Fast Ethernet. However, as newer network designs heavily utilized switching with 100-Mbps links to theses routers, a potential design bottleneck can be created. Although this is not county a problem, the migration of services away from the workgroup and to word the enterprise can potentially lead to slower network performance.

The solution demonstrated by using Gigabit Ethernet switches that provide aggregation between routers in a routed backbone. Gigabit Ethernet and Gigabit switching are used to improve speed and capacity between the routers. Gigabit Ethernet switch is placed between the routers for improved throughput performance. You can also used industrial Ethernet router for that purpose. By implementing this design, a fast Layer 2 aggregation is utilized, creating a high-speed core.