ClassLan

Notes 18-05 Networks

Cabling

Coaxial Plenum-Rated – coating does not produce toxic gas when it burns
Coaxial cable is rated according to RG-type
Nost common - Thinnet or Cheapnet (Ethernet 10Base2 cable)

RG-8 Thicknet 10Base5 Solid copper
RG-58 AU Thinnet 10Base2 Stranded copper

Connectors: BNC (male/female connectors, T-connectors, barrel
connectors and 50-ohm terminator cap)

Vampire Tap: used with Thicknet – uses 15-pin AUI connector
Cable than runs from AUI port is a DIX cable (aka Transiever cable)


Twisted-Pair Extremely popular

STP/UDP Shielded twisted-pair/Unshielded twisted-pair

Category 2 4Mbps (8 wires/4 twisted pairs)
Category 3 10Mbps (8 wires/4 twisted pairs, 3 twists per
foot)
Category 4 16Mbps (8 wires/4 twisted pairs, 3 twists per
foot)
Category 5 100Mbps (8 wires/4 twisted pairs, 3 twists per
foot)
Category 5e 1Gbps (8 wires/4 twisted pairs, more than
3 twists per foot)
Category 6 1Gbps+ (8 wires/4 twisted pairs, 3 twists but
are oriented differently than others)

Uses RJ connectors – RJ11 or RJ45


Fibre-Optic Made of Thin, flexible glass or plastic fibre surrounded by a rubber
coating. Immune from electrical or radio interference. High cost
100Mbps to 1Gbps over a distance of several miles
Single-mode (3,000 meters) or Multimode (2,000 meters; multimode signal degrades quicker and has lower available bandwidth)
Connectors: SC (Square) Connector
ST (Straight Tip) Connector
Both a good for 1000 matings


RS-232 Serial Cable
Can connect into a Multiplexer (like a Hub but for serial)


Wireless Infrared light, laser, narrow-band, microwave, spread-spectrum
radio


NIC (Network Interface Card)
Half-Duplex/Full-Duplex
HD: Cannot send and recive data at the same time
FD: Can and recive data at the same time
NIC Configuration – IRQ Address, I/O Address, DMA Address
‘Link Light’
Media Access Methods – CSMA/CD, CSMA/CA, Token Passing,
Polling


Connectivity Devices

Repeaters Amplifies voltages (signal) between similar network segments
Not only boosts single but also the noise.
Works on the Physical layer of the OSI model (ex: 10BaseT)
Hubs are multi-port repeaters
5-4-3 Rule: 5 Network Segments-4 Repeaters-3 Segments can be populated


Hubs Provides a physical, electrical station to all connected ports. Sends
information unintelligently to all connections (except sender)

Active Hubs: Amplify and some cleanup signal
Passive Hubs: Connect all ports electrically


Switches Works on Data Link Layer of the OSI model (some work on level
3)


Bridges Works on the Data-Link layer of the OSI model.
Join similar topographies and divides network segments
Bridges are not able to distinguish 1 protocol from another
Bridges can filter out noise


Routers Works on the Network later of the OSI model


Brouters Combined Bridge and Router – Used to connect dissimilar network
segments and also to route one specific protocol


Gateways connect dissimilar network environments and archetures
For example – Windows NT to Novell NetWare
Some gateways can use all 7 OSI levels, but frequently run on the
Application level.

posted by ClassLan @ 9:50 AM