Transcript Networking - Super Substitute Teachers

Topologies, Mediums
Physical vs. Logical Topology
Physical
Logical
 Physical layout of devices on
 The way data is transmitted
a network
 Ex: Bus, star, ring, hybrid,
wireless
over a physical topology
 Bounded by network protocols
 Describes how data moves
across a network
 Ex: token ring, 802.11
We will go into more depth through out this class
Physical Topology - Bus
 Each system on a
network is connected in
a line
 Terminators are placed
on each end
Physical Topology - Bus
Advantages
Disadvantages
 Easy to install
 Out-of-date technology
 Costs are usually low
 If cable breaks, whole
 Easy to add systems to
network is down
 Can be difficult to
troubleshoot
network
 Great for small networks
Physical Topology - Ring
 Each system is connected to its
respective neighbor forming a
ring
 Same advantages and
disadvantages as Bus Topology
 Only difference between the
two are that it doesn’t have any
terminators
 Token ring protocol is used to
pass data around the network
Physical Topology - Star
 Systems are connected
to a central device
 Very popular topology
Physical Topology - Star
Advantages
Disadvantages
 Easy to install
 Costs more then other bus, or
 Easy to add devices to
ring topology
 If the central device fails, the
network goes down




network
One break does not bring
whole network down
Easier to troubleshoot
Widely used
Centralized management
Physical Topology - Hybrid
 Combinations of two or
more topologies
 What topologies do you
see in this picture?
Physical Topology - Wireless
 Computers connect to a network wirelessly
via a WAP
 No wires, it’s magic!
Logical Topologies
 Token Ring – Used in Ring topologies
 Localtalk– Used in older apple networks
 IEEE 802.11 – Standard for wireless networking
Medium – Twister pair
 Type of wiring in which 2 conductors are
twisted together to reduce electromagnetic
interference
 Two main types: Unshielded twisted pair
and Shielded twisted pair
 Max length of 100m
 UTP has many different grades from CAT1
to CAT6
Examples of Twister pair cables
 RJ45- Standard type of connector for
network cables
 RJ11 – Cable used for telephone wires
Medium – Coaxial Cable
 Copper center wire
 Two types: Thinnet vs
Thicknet
 Thinnet can run up to at 185
meters. It has a smaller
diameter and more flexible
 Thicknet is thicker but can
run up to 500 meters
 Where do you see coaxial
cable?
Medium – Fiber Optic cable
 Carries data over the line
using light
 Can carry large
quantities of data over
longer distances(2km)
 Immune to
electromagnetic
interference
Medium – Radio waves
 A specific frequency
range is used for
computer networks
Summary
 Physical vs logical topology
Bus, ring, star, hybrid, wireless
 Mediums
Twisted pair, coaxial cable, fiber optic, radio waves