Ethernet Network architecture

ETHERNET NETWORK ARCHITECTURE

Ethernet Network Architecture is a baseband architecture which uses a bus topology, usually transmits at 10 Mbps, and relies on CSMA/CD (Carrier-Sense Multiple Access with Collision Detection) to regulate traffic on the main cable segment.
The Ethernet media is passive, which means it draws power from the computer and thus will not fail unless the media is physically cut or improperly terminated.
Ethernet breaks data down into packages in a format that is different from the packet used in other networks. Ethernet breaks data down into frames.
A frame is a package of information transmitted as a single unit. An Ethernet frame can be between 64 and 1,518 bytes long, but Ethernet frame itslef uses at least 18 bytes; therefore, the data in an Ethernet frame can between 46 and 1,500 bytes long. Every frame contains control information and follows the same basic organization.
The Ethernet frame usually consists of several sections/field:

Frame Field Description:
Preamble: Marks the starts of the frame.
Destination and Source: The origin and destination addresses.
Type: Used to specify the Network layer protocol (IP or IPX).
CRC: Error checking field to determine if the frame arrived without being corrupted

Network Introduction

Network Cabling

Wireless Network

Network Interface Card

OSI Model

Protocols

Ethernet - Network architecture

Token Ring - Network architecture

AppleTalk and ArcNet - Network architectures

Repeaters, Bridges, Routers, and Gateways

E-mail Standards
Modem & Async Comm.

T1, T3, and Switched 56 Digital Connectivities

Packet-Switching Network,Frame Relay and ATM

ISDN & FDDI

There are several different 10 Mbps Ethernet topologies, some examples are:

10Base2
This topology is called 10Base2 because it transmits at 10 Mbps over a baseband wire and can carry a signal roughly two times 100 meters (the actual is 185 meters). This type of network uses thin coaxial cable, or thinnet, which has a maximum segment length of 185 meters. There is also a minimum cable length of at least 0.5 meters (20 inches). There is also a 30 computer maximum per 185 meters segment.
The 5-4-3 rule is commonly used in a 10Base2 network. A thinnet network can combine as many as five cable segments connected by four repeaters, but only three segments can have stations attached. Thus, two segments are untapped and are often referred to as inter-repeater links. This is known as the 5-4-3 rule.
10Base5
The specification for the 10Base5 topology is 10 Mbps, and 500-meter segments. This topology is also called standard Ethernet. It uses thick coaxial, or thicknet. Thicknet generaly uses a bus topology and can support as many as 100 nodes (stations, repeaters, and so on) per backbone segment. The backbone, or trunk segment, is the main cable from which transceiver cables are connected to stations and repaters. A thicknet segment can be 500 meters long for a total network length of 2,500 meters (8,200 feet).

There are also two emerging Ethernet standards that can meet the high-bandwidth applications, they are:

100VG-AnyLAN
100VG (Voice Grade) AnyLAN is an emerging networking technology that combines elements of both Ethernet and Token Ring. It is currently refined and ratified by the IEEE 802.12 committee. The 802.12 specification is a standard for transmitting 802.3 Ethernet frames and 802.5 Token Ring packets. This technology is also known as 100baseVG, VG, and AnyLAN. Some of the current 100VG-AnyLAN specifications include:

A minimum data rate of 100 Mbps.

Ability to support a cascaded star topology over Category 3, 4, and 5 twisted-pair and fiber-optic cbale.

The demand priority access method which allows for two priority levels (low and high)

Ability to support an option for filtering individually addressed frames at the hub to enhance privacy.

Support for both Ethernet frames and Token Ring packets.

100BaseX Ethernet
This standard, sometimes called Fast Ethernet, is an extension to the existing Ethernet standard. It runs on UTP Category 5 data-grade cable and uses CSMA/CD in a Star wired bus, similar to 10BaseT where all cables are attached to a hub.
The 100BaseX Ethernet incorporates three media specifications:

100BaseT4 (4-pair Category 3, 4, or 5 UTP)

100BaseTX (2-pair Category 5 UTP or STP)

100BaseFX (2-strand fiber-optic cable)

These media are described as follows:
Value = 100 means the Transmission speed at 100 Mbps or 100 megabit per second.
Value = Base means the Signal type is a Baseband type.
Value = T4 means the Cable type that Indicates twisted-pair cable using four telephone-grade pairs
Value = TX means the Cable type that Indicates twisted-pair cable using two data-grade pairs
Value = FX means the Cable type that Indicates fiber-optic link using two strands of fiber-optic cable.

BACK TO MAIN PAGE