Introduction To Computers Ethernet Networks

Ethernet Architecture Ethernet is the most popular WIRED LAN standard Wi-Fi is gaining in popularity, but it is not wired There are lesser used architectures like Fieldbus The ethernet standard defines: The medium used How data is packaged and accessed Possible topologies Cable length Speed of network The standard is updated routinely to introduce new technology

Network Interface Card Every host on the network will need a NIC (Network Interface Card) NICs will provide a MAC address for every host, which is a physical address assigned to that interface, and provide a transceiver, which takes the binary data of our host and applies it to our network medium The type of transceiver, (and therefore NIC) will depend on the network media Ethernet currently supports two connection media Copper wire through ethernet and coaxial Fiber Optic cable Wi-Fi is NOT part of the ethernet standard

Networking Devices If we are using a star topology (the most common topology in modern ethernet networking), we can use either hubs or routers when choosing a central connection point for our network Hubs tend not to be used much, because switches provide a lot more functionality Hubs will merely repeat a signal from one port onto the others, whereas a switch will use MAC addresses to forward the message to the right host Routers will connect networks together, and provide a connection to a public network like the internet Bridges will expand a network. The most common form right now is a wireless bridge which will add WIFI enabled devices to the same network the bridge is connected to

Topology Older ethernet networks used a physical bus topology, with all devices connected to a central trunk Newer ethernet networks use a physical star topology, with all of the host nodes connected to central device, such as a hub or switch A logical bus topology is used when the network uses a physical bus topology or a physical star topology with a hub A logical star topology is used when the network uses a physical star topology with a switch or router

Ethernet Naming Standards To identify the speed of an Ethernet network we use specific Ethernet naming standards, which consist of numbers and letters The number at the beginning denotes the transmission speed Followed by the word BASE. This stands for baseband signaling, the type of signaling used on ethernet networks After that, we have a dash followed by a letter. This letter defines the transmission medium and the maximum cable length

Ethernet Naming Examples 10BASE-T 10 megabit twisted pair, 100 meter max length 100BASE-TX 100 megabit twisted pair, 100 meter max length 1000BASE-T 1000 megabit twisted pair, 100 meter max length 10GBASE-T 10 gigabit twisted pair, 100 meter max length 10BASE-FL 10 megabit fiber optic, 1000 - 2000 meter max length 100BASE-FX 100 megabit fiber optic, 412 meter max length 1000BASE-SX 1000 megabit fiber optic, 220-550 meter max length (cable quality) 1000BASE-LX 1000 megabit fiber optic, 550 meter or 10km max length (mode) 10GBASE-SR / 10GBASE-SW 10 gigabit multimode fiber optic, 300 meter max length 10GBASE-LR / 10GBASE-LW 10 gigabit single mode fiber optic, 10km max length 10GBASE-ER / 10GBASE-EW 10 gigabit single mode fiber optic, 40km max length

Power Over Ethernet Power over Ethernet (PoE) technology can be used to distribute electrical power along with network data on twisted-pair Ethernet cabling (CAT 5 or higher). Not fiber optic. Why? Power is usually supplied by a PoE-enabled Ethernet switch. PoE is commonly used to power network devices that are located where physical access to a power outlet may not be available, like, a surveillance camera mounted on a tall pole You can use a PoE injector to add PoE capability to regular non-PoE network links. They upgrade existing LAN installations to PoE, and provide a solution where fewer PoE ports are required. To upgrade a network connection to PoE, patch it through the PoE injector. Power injection is controlled and automatic

Duplexing When using a hub all devices share the transmission media, and can either send or receive, but not both at the same time. This is called half-duplex When using a switch, since there is no collision detection or chance for collision - devices can send and receive at the same time. This doubles the rated bandwidth, but requires NICs that are full-duplex capable and a switch with dedicated ports (one device per port)

Ethernet over HDMI and Ethernet over Power Line With ethernet over HDMI networked entertainment devices can share their connection without additional ethernet cables. Look for devices with HEC functionality Ethernet over powerlines allows for communication over existing AC power lines. A device is plugged into an AC power which uses multiplexing at a higher frequency than the AC power to another ethernet over power device. This can be helpful when you are unable to run ethernet into a specific room