Since the late 1990s, Ethernet connections have become the de facto standard for local area networks.
In this article, we'll focus on the hardware components involved in using Ethernet in a 10/100baseT network--currently the most popular standard--including cable pinouts and specs, network cards, hubs, and switches.
Inside: Building an Ethernet LAN
- Phase 1: Technology choices and costs
- Phases 2-3: Plan and purchase
- Phase 4: Build
- Buyer's Guide: Broadband routers
Background on Ethernet
So you want to build an Ethernet LAN? Or maybe you're wondering exactly what Ethernet is. Well, Ethernet (the name commonly used for IEEE 802.3 CSMA/CD-carrier sense multiple access, collision detection) is the dominant cabling and low-level data delivery technology used in local area networks (LANs).
First developed in the 1970s, it was published as an open standard by DEC, Intel, and Xerox (or DIX) and later described as a formal standard by the IEEE. Following are some Ethernet features:
Ethernet transmits data at up to 10 million bits per second (10Mbps). Fast Ethernet supports up to 100Mbps. Gigabit Ethernet supports up to 1000Mbps.
Currently, 10BaseT and 100BaseT (Fast Ethernet) Ethernets are the most common, and both can be built with twisted-pair cabling.
Data is transmitted over the network in discrete packets (frames), which are between 64 and 1518 bytes in length (46 to 1500 bytes of data, plus a mandatory 18 bytes of header and cyclical redundancy code [CRC] information).
Each device on an Ethernet operates independently and equally, precluding the need for a central controlling device. Ethernet supports a wide array of data types, including TCP/IP, AppleTalk, IPX, and more.
To prevent the loss of data, when two or more devices attempt to send packets at the same time, Ethernet detects collisions. All devices immediately stop transmitting and wait a randomly determined period of time before they attempt to transmit again.
Phase one : pre-planning
The first decision is a technology and cost decision. Will your network be 10BaseT, 100BaseT, or Gigabit Ethernet?
Can you afford 100Mbps from POP (Point of Presence, your connection to the outside world) to client or do you just need the higher bandwidth on your backbone? The following is a comparison of the technologies.
Standard Ethernet (10BaseT)
Standard Ethernet (10BaseT) uses RJ-45 connectors on unshielded twisted pair (UTP) or shielded twisted pair (STP, also called Plenum) cable and operates at 10Mbps.
Using a star topology, all computers connect to a Hub/Switch using patch cables with RJ-45 male connectors on both ends. These hubs can be linked to increase the number of ports available for patch cables; however, no more than three hubs should be linked together.
Sometimes these hubs/switches have "uplink" ports that allow them to be connected to each other using special cables that blend two hubs into one without daisy chaining. Both clients and hubs have RJ-45 female connections.
Ideally, Category 5 patch cables should be used in 10BaseT (so that you can upgrade to 100BaseT without recabling).
10BaseT networks are wired (within the plugs and ports) according to EIA/TIA 568B specifications. Maximum cable length is 100 metres. Maximum number of devices is 1024, although performance would be unacceptable long before this number is reached.
Fast Ethernet (also called 100BaseT)
This technology is essentially the same as 10BaseT in terms of specifications and limitations, but it has higher bandwidth; and, the network interface cards (NICs) and the ports on the hubs and switches operate at 100Mbps.
It is very common to have a 10BaseT LAN that runs from clients to a central switch or hub and a 100BaseT LAN as the backbone for your servers.
Gigabit Ethernet
Currently the cutting edge of Ethernet technology, Gigabit Ethernet supports data transfer rates of 1 Gigabit (1000 megabits) per second. The first Gigabit Ethernet standard (802.3z) was ratified by the IEEE 802.3 Committee in 1998.
10G Ethernet
10 Gigabit Ethernet shares the same name as well as the same frame format as its lower-speed brethren, but that is where the similarities end.
The emerging specification, which is expected to be ratified in the second quarter of 2002, was designed for carrier networks as well as enterprise LANs, costs 20 to 90 times more than current Gigabit Ethernet links, and is expected to ramp up at a slower pace than its predecessors.
As my Institute want to purchase the Router , switchses and NIC this article is very much useful to us to purchase the proper equipment for
our network setup. Thanks very much for your
article.