Transcript Chapter 8 Intro

Chapter 8
ITE 1
Basic Networking
Networking Basics
• Two Basic Types of Connections Are:
• WAN
• Wide Area Network
• Think Modem - Long distances
• LAN
• Local Area Network
• Think This Room
Connection Media
• Copper Cabling
• Coax or UTP
• UTP is limited to 100 meters
• Fiber
• Uses glass strands to carry pulses of light
• No electrical issues - Longer Distances
• Wireless
• Radio signals or infrared
Connection Media
• UTP Cabling
• Unshielded Twisted Pair
• Uses Copper Wire
• Number of twists and number of
conductors determine category
number (Cat 3, Cat 5, Cat 6 etc.)
Oddball WAN Media
• Power lines (PLC) can be used to
carry both voice and data.
• It can actually provide higher
bandwidth than phone lines (PSTN)
Why Network?
• Share files and resources
• Lower Cost Software Licensing
• Central Administration
WLAN
• Are wireless LAN’s
• Can cover small or large areas.
• Small area connections use shared
bandwidth.
Network Types
• There are two basic types of networks
• Peer to Peer
• All machines are equal
• No central administration
• Client/Server Networks
• Centrally administered
• Lots of control and security, but increased
overhead
• Easy data backup and centralized access to data
Bandwidth
• Network speed is measured in
Bandwidth
• Bps - Bits per second
• Kbps - Kilobits per second
• Mbps - Megabits per second
Communication Direction
• Simplex
• One way transmission
• Think Radio Station
• Half-Duplex
• One Direction at a time
• Think Walkie Talkie
• Full-Duplex
• Both directions at once
• Think telephone
Network Addressing
• Broken into three classes
• Class A:
• 1st Octet is a Network Address
• Class B:
• 1st and 2nd Octets are Network Addresses
• Class C:
• 1st, 2nd and 3rd Octets are used to identify
the network address
Network Addressing
• The remaining addresses are used
for individual devices on each type
of network.
Network Addressing
• Addressing can be done by the
administrator and manually added
to each machine or
• Done automatically through a
process called DHCP where the
address are handed out on a
temporary basis
Network Addressing
• Network Addressing has 3 Parts
• IP Address - Must be unique for every
machine on the network
• Subnet Mask - Should be the same for every
machine on the network
• Tells the network which part of the IP is for the
network address and which part is for the
individual devices
• Gateway - Tells the machine where to send
the packets that go to the internet
• Machines can communicate locally without the
proper gateway address.
Protocols
• Protocols are a set of rules that
govern communications
• See page 8.3.4 for a list of common
protocols
ICMP
• Internet Control Message Protocol is used
to send messages between devices
regarding network conditions
• One type of ICMP is called Packet
Internet Groper or PING
• It is used to test end to end connectivity
between devices
• Tracert shows the whole route the
packets took along with timing.
How Information is Sent
• Files are broken down into
segments.
• The segments get headers and
trailers added for addressing and
error checking.
• This process is called
Encapsulation.
Network Devices
• Hubs
• Hubs are “Dumb Devices” They are
really multi-port repeaters.
• They simply send anything they receive in
any one port out all of their other ports.
• They run at Half-Duplex only.
• They extend the network without
breaking it into segments as switches and
routers do.
Network Devices
• Routers
• Routers make forwarding decisions
based upon programming.
• They are very smart devices and can
dynamically reroute packets as network
conditions change.
Network Devices
• Switches
• Switches and Bridges (Bridges are
single-port switches) are smarter than
hubs.
• They make forwarding decisions based
upon Mac (Hardware) Addresses
• They are good because they block
unwanted traffic.
Network Topographies
• Ethernet Standard (IEEE 802.3) systems
use a Star physical topology
• But their logical topology is actually a bus
topology
• There are other types including a Mesh
Topology where everything is connected
to everything else and a Ring Topology
which is just as it sounds.
Ethernet Standards
• Wireless Standard can be found on
page 8.7.2
• One of the most common is 802.11g
which runs at speeds up to 54 mps.
How LAN’s Work
• To avoid collisions where multiple
devices try to talk at once:
• Ethernet uses CSMA/CD
• When a collision occurs all devices back of
a random amount of time, then listen to
see if the coast is clear before resending
Models
• There are two models for
explaining how Networking is done.
• One is TCP/IP
• The other is the OSI Model
• See pages 8.8.3 for an explanation
of the different models and how
they relate to each other.
OSI Model
• Explains how
things work.
• Makes it so
equipment and
software from
different
sources will
work together.
OSI Model
• Data link layer
controls
physical
addressing
otherwise
known as the
MAC address.
VoIP
• What is VoIP?
• It’s voice (As in Telephone) over a
computer network. (Voice Over IP)
• Advantage: It’s very cheap. Think Vonage
• Disadvantage: If your internet goes down
so does your phone service.
Other Odd Ways of
Connecting
• PLC
• Carries Voice and Data Across Power
Lines
• Requires no control wiring for
electrical devices at the customer’s
end.
• Actually has more bandwidth than
most other WAN technologies
Other Ways To Connect
• ADSL
• Uses existing phone lines
• Faster download (Downstream) speeds
than up upload (Upstream) speeds.
• Limited distance from the phone company
switching center.
Other Ways to Connect
• ISDN
• Uses 2 phone lines - 3 Channels, 2B
and one D.
• Faster than dialup, but slower than
cable or DSL.
• Expensive
• Called BRI
• Not used much anymore.
That’s It!
• Good luck on the test!