Ethernet Network Basics: Types, Services, and Standards

This tutorial covers the fundamentals of Ethernet networks, including:

• Ethernet over copper
• Ethernet Business
• Gigabit Ethernet
• 40Gbps Ethernet PHY
• 100Gbps Ethernet PHY
• 10Gbps Ethernet PHY
• Ethernet types

Ethernet networks are widely used for connectivity between PCs in both small and large businesses. While networks with speeds of 10Mbps and 100 Mbps are common for LAN networking, the latest developments support speeds of 1Gbps and even 100Gbps using Ethernet technologies. Networks operating at 100Gbps are often referred to as Gigabit Ethernet. Ethernet hubs and switches are commonly used to connect multiple desktop PCs and laptops. The Ethernet standard is defined in IEEE 802.3.

Other wired LAN technologies, such as FDDI, token ring, and ARCNET, are evolving rapidly and, in some cases, replacing traditional Ethernet networks. Despite this competition, Gigabit Ethernet continues to expand and replace other high-bandwidth and high-speed technologies, like fiber optics.

As shown in the figure, a typical Ethernet network involves PCs connected to an Ethernet switch, which is then connected to a hub or a router via a hub. The router provides a connection to the Internet service provider’s modem, which may be DSL compliant. Nowadays, Gigabit Ethernet servers are also being integrated into Ethernet LANs.

The three physical layers commonly used in Ethernet networks are 10 Base T, 100 Base T, and 1000 Base TX, providing speeds of 10Mbps, 100 Mbps, and 1Gbps respectively.

According to IEEE 802.3, an Ethernet frame consists of a start frame delimiter, header, payload, and CRC parts. An Ethernet frame is also referred to as a data gram or packet. The Ethernet header contains the source and destination Ethernet addresses. A 32-bit CRC (Cyclic Redundancy Check) is used for error correction after the frame is received at the destination PC. For a deeper dive, refer to resources on OSI and TCPIP layers.

The following section outlines Ethernet service providers.

Ethernet Business Services

The following are Competitive Local Exchange Carriers (CLECs) and Incumbent Local Exchange Carriers (ILECs) that provide Ethernet business services in North America. These businesses offer wireline carrier services such as CableTV, internet, CLEC, fiber rings, Multiple Service Operator (MSO), DSL, and so on.

Major CLECs

• AT & T: Provides long-distance network services, with a primary focus on CLEC, hosting, and internet backbone solutions.
• Broadview Networks: Previously based in New York, they offered voice/data services to small and medium enterprises. They are now merged with BridgeCom Holdings.
• Time Warner Telecom Inc.: Sells fiber to wireless and wireline carriers across 22 states, operating as both a wholesaler and retailer for small and medium-sized businesses.
• XO communications: Operates fiber rings in metropolitan cities and a nationwide fiber network. Formerly known as NEXTLINK.

Other Ethernet service providers include 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, and XO Communications Inc. Their primary business is as CLECs.

The carriers operating 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: Core business focuses on mobile wireless, independent ILEC, internet backbone, and retail/wholesale long-distance carrier services.
• ALLTEL Corporation: Primarily an independent ILEC and cellular service provider, ranking as the sixth largest in the United States with approximately 3 million lines.
• Century Tel Inc.: Main business encompasses cable TV, interstate fiber network, and ILEC operations. It stands as the 8th largest carrier in the United States.