Ethernet network basics

This tutorial section on Ethernet basics covers following sub topics:
Ethernet over copper  Ethernet Business  Gigabit Ethernet  40Gbps Ethernet PHY   100Gbps Ethernet PHY   10Gbps Ethernet PHY   Ethernet types  

Ethernet networks are popular as it is used for connectivity between various PCs in small and large business enterprises. Networks with 10Mbps and 100 Mbps speed are common for LAN networking. The latest developments cater speed of 1Gbps and even 100Gbps using Ethernet technologies. Networks with 100Gbps speed are referred as Gigabit Ethernet. We have seen Ethernet hubs and switches in use to connect multiple desktop PCs and laptops. The Ethernet is standardized in IEEE 802.3 standard. The other wired LAN technologies such as FDDI, token ring and ARCNET are evolving very fast and replacing conventional Ethernet networks. Inspite of this competition gigabit Ethernet is extending and replacing other broad bandwidth and high speed technologies such as fiber optic.

Ethernet network

As shown in the figure, in a typical Ethernet network PCs are interfaced to Ethernet switch and Ethernet switch is connected with hub or to router via hub. The router will have connection to internet service provider's modem device. This modem can be DSL compliant. Now-a-days gigabit Ethernet servers are also connected with Ethernet LAN.

The three physical layers viz. 10 Base T, 100 Base T and 1000 Base TX are used in Ethernet networks which provides speeds of 10Mbps, 100 Mbps and 1Gbps respectively. As per IEEE 802.3 Ethernet frame consists of start frame delimiter, header, payload and CRC parts. Ethernet frame is also referred as data gram or packet. Ethernet header carry and source and destination Ethernet addresses. 32 bit CRC is used for error correction after the frame is received at the destination PC. For more refer our page on basics of OSI and TCPIP layers.

The next section provides Ethernet service providers.

Ethernet Business services

Following are competitive local exchange carriers (CLECs) and Incumbent local exchange carriers (ILECs) providing Ethernet business services in North America. These business establishments provide wireline carrier services such as CableTV, internet, CLEC, fiber rings, multiple service operator (MSO), DSL and so on.

Major CLECs

AT & T : This wireline carrier provides long distance network services. The main business is CLEC,hosting, internet backbone solutions etc.
Broadview Networks: This New York based provider take care of voice/data services to small and medium enterprises. Now it is merged with BridgeCom Holdings.
Time Warner Telecom Inc.: It sells fiber to wireless and wireline carriers across 22 states. It operates as wholesaler as well as retailers for small and medium business establishments.
XO communications: It operates fiber rings in metropolitan cities and nation wide fiber network. It was earlier known as NEXTLINK.

The other Ethernet service providers are AT&T, Broadview networks, citizens communications company, corvis corporation, Covad communications Group,Inc., IDT corporation, MCI,Inc., TELUS Corporation, MCLeodUSA Incorporated, BullsEye Telecom, Earthlink business,Integra,Lumos networks, megapath, Surewest, Time Warner Telecom Inc., XO communications Inc. Their primary business is as CLECs. The carriers which operate in North America are briefly described below.

Major ILECs

The Ethernet business service providers as ILECs are BCE Inc., ALLTEL corporation, Century Tel Inc., Citizens communications company, Telmex, Telus Corporation, AT&T, FairPoint Communications, Frontier Communications, Hawaiian Telcom, MegaPath, Sprint,Verizon, Windstream etc. Few of these are described below.

Sprint Corporation: The main business is mobile wireless,independent ILEC,internet backbone and retail/wholesale long distance carrier.
ALLTEL Corporation: The primary business is independent ILEC and cellular service provider. It is the sixth largest in the United States with about 3 million lines.
Century Tel Inc.: The main business is cable TV, interstate fiber network and ILEC. It is the 8th largest carrier in United States.

RF and Wireless Terminologies