Transcript Chapter 7- Networking Concepts

PC SUPPORT &
REPAIR
Chapter 7
Networking Concepts
Objectives
■ After completing this chapter, you will meet these objectives:
Explain the principles of networking.
Describe types of networks.
Describe basic networking concepts and technologies.
Describe the physical components of a network.
Describe LAN topologies and architectures.
Identify standards organizations.
Identify Ethernet standards.
Explain OSI and TCP/IP data models.
Describe how to configure a NIC and a modem.
Identify names, purposes, and characteristics of other
technologies used to establish connectivity.
o Identify and apply common preventive maintenance techniques
used for networks.
o Troubleshoot a network.
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Host Devices
■ Any device that sends and receives information
on the network AND IS DIRECTLY CONNECTED
TO IT
o Ex: Printer connected via Ethernet or Wi-Fi is a
HOST
o Ex: Printer connected via USB to a PC is a
PERIPHERAL
Intermediary Devices
■ Exists between host devices
■ Ensures that data flows from one host to
another host
Network Media
■ The channel the message is
carried over
■ Copper
o Sends electricity through cable
■ Fiber Optic
o Uses glass/plastic fibers to carry
light pulses
■ Wireless
o Uses radio signals, infrared, or
satellite
Network Media Icons
Activity- Identify Device/Media
■ Host, Intermediary, or Media
Bandwidth & Latency
■ # of bits transmitted per second
■ Data is broken into chunks, called packets
o Packets have headers which tell how to put the chunks
back together & source & destination addresses
bits per second
bps
b/s
kilobits per second
kbps
kb/s
megabits per second
Mbps
Mb/s
gigabits per second
Gbps
Gb/s
■ Latency
o Time it takes data to travel
o More devices = more latency
Bandwidth & Latency
Data Transmission
■ Simplex
o Unidirectional, one-way
■ Half-Duplex
o Send OR receive at a
time
■ Full-Duplex
o Send AND receive at
same time
o Better network
performance
LAN
■ Small area
■ Owned by individual,
business, IT dept.
■ Share resources
■ Security & access
control policies
■ GCIT is a LAN
■ Your home is a LAN
WLAN
■ LAN with wireless
■ Wireless devices
connect to AP
o AP connects to
wired part of
network
■ Avg. distance inside
is 100ft
o Outside is more
PAN
■ Personal Area Network
■ Connects mouse,
keyboard, printer,
smartphone, tablet
within range of a
person
■ Bluetooth
o IEEE 802.15.1
o Handles voice & data
o 2.4GHz
MAN
■ Metropolitan Area
Network
■ Spans across
campus or city
■ Buildings connect
via fiber or
wireless
WAN
■ Connects LANs that are geographically
separated/far away
■ WAN is owned by service provider
■ Internet is biggest WAN
Peer-to-Peer Networks
■ Small group of computers connected
o 10 or less
o Can share files, printers (NO SERVER)
o Each PC is responsible for itself
■ Disadvantages
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No central admin
No central control of security
Hard to manage with more devices added
No central backups; each on their own
Client-Server Networks
■ Client requests service;
server provides the service
■ Administrators
o Maintain servers & control
user access
■ Client device has client
software for access to server
■ Access central storage
o Backed up daily
Activity- Matching
Review- 4Q
■ Which type of network includes an AP?
o WLAN
■ The Internet is which type of network?
o WAN
■ Explain what an AP does.
o Connects wireless devices to the wired network
■ What does an Ethernet cable use to send data?
o Electricity
Review- 3Q
■ Which type of network would daily backups be
done on?
o Client-server
■ Which network would have better, secure
access?
o Client-server
■ Which network would you typically store data on
your own hard drive?
o Peer to peer
NETWORKING
STANDARDS
7.2
Open Standards & Protocols
■ Open Standards
o Interoperability, competition, innovation
o Everything works no matter who makes it
■ Protocols
o Set of rules for communication
OSI Model
■ Before 1983, network devices were proprietary
o Had to buy all from same vendor or it wouldn’t work
■ OSI model created standards to follow
■ OSI model layers break down the
communication process between devices
OSI Model
OSI Model
Layer # Layer Name
Description
7
Application
Provides network access to applications
SMTP; HTTP; DHCP; FTP; Telnet
6
Presentation
Transforms data to a format
5
Session
Establishes, manages, terminates sessions
4
Transport
Reliable transport; flow control; retransmission;
TCP; port numbers; segments
3
Network
Routing; Logical (IP) addressing; packet
2
Data Link
Physical (MAC) addressing; access to media
frame
1
Physical
Bits; electricity
Activity
■ OSI Model & Handout
Review- 4Q
■ Name the OSI layers from 7 to 1
o Application, Presentation, Session, Transport,
Network, Data Link, Physical
■ At which layer is IP addressing?
o Network-3
■ At which layer is MAC addressing?
o Data Link-2
■ At which layer are cables & wireless?
o Physical-1
Review- 3Q
■ As data is passed from one layer to the next,
control info (headers) are added. What term
describes this adding of info to the data
through the layers?
o Encapsulation
■ Which layer of the OSI deals with IP addresses?
o Network
■ Which layer of the OSI deals with MAC
addresses and gaining access to the cables?
o Data Link
TCP/IP Model
Protocol Data Unit (PDU)
■ As message is prepared to go out, lots of stuff
is added (encapsulated) at each layer
o ENCAPSULATION PROCESS
■ PDU is the data package at each layer
PDUs in the Models
Layer # Layer Name
PDU
7
Application
Data
6
Presentation
Data
5
Session
Data
4
Transport
Segments
3
Network
Packets
2
Data Link
Frames
TCP/IP Model
Application
Transport
Internet
Network Access
1
Physical
Bits
Encapsulation Process
Activity
WIRED & WIRELESS
STANDARDS
7.2.2
CSMA/CD
■ Ethernet is contention-based/non-deterministic
o Data contends or shares for a spot on the media
o Doesn’t know when it’ll get access to it
■ Listens for signal on media
o No signal = transmit data
o Transmit at same time= collision
■ Devices do not keep track of whose turn it is
■ More collisions= less throughput
o SOLUTION: CSMA/CD
CSMA/CD on Ethernet Networks
■ Listens for silence
o Silence= transmit data
Today’s Ethernet is full-duplex so
there are rarely collisions
■ If devices transmit at same time, collision
o They send a jam signal
o Backoff random time, listen for silence, retransmit
■ Collisions not a problem much anymore
o Using switches & full-duplex, this is not a problem
anymore
Ethernet Cable Standards
■ Speed; Baseband; Twisted Pair
Ethernet Standard
Media
10Base-T
Cat 3
100Base-TX
Cat 5
1000Base-T
Cat 5e, Cat 6
10GBase-T
Cat 6a, Cat 7
CSMA/CA
■ Carrier Sense Multiple Access with Collision
Avoidance
o Used in wireless networks
o Used to avoid collisions by waiting before
transmitting
■ Approx. time it’s going to take is included in frame
■ All wireless devices know how long wireless will be
unavailable
o Wireless is half-duplex
o More wireless devices on an AP, the slower it will be
Wireless Security
■ Authentication
o Open
o Pre-Shared Key (PSK)
■ WEP- weakest
■ WPA- uses TKIP encryption
■ WPA2- strongest; uses AES encryption
Review- 4Q
■ You’d like to add wireless with speeds up to
1.3Gbps. Which spec should you buy?
o 802.11ac
■ What is the max speed of G?
o 54Mbps
■ What connects wireless devices to a wired
network?
o AP
■ What wireless spec is not compatible with others?
o 802.11a
PHYSICAL
COMPONENTS
OF A NETWORK
7.3
Modem
■ Connects you to the
Internet through the ISP
■ Converts digital to
analog/analog to digital
o Modulate/demodulate
■ Cable modem, DSL
modem, Dial-up modem
Hubs
■ Simple
■ Extends network
■ Data goes in one port & out all
others
o No thinking involved
o Relies on devices to decide on
message
■ Creates more network traffic
■ Not used anymore
Hub Network
Bridges
■ Divided/filtered LAN segments
■ Reduces traffic
Switch
■ Data sent in small
packets
■ MAC addresses added
o Packaged into a FRAME
■ Data enters a port, then
sent out the one port
o Smarter than bridge
o Knows MAC address on
each port
■ MAC address table
Switch Network
Wireless Access Point (WAP)
■ Allows wireless
devices to connect
to wired network
o Uses radio waves
■ Limited range
o May have several in
building
Routers
■ Connects different
networks
■ Reads IP addresses
o Directs packets to
networks
o Doesn’t care about
specific PC’s
■ Multipurpose Device
o Router, Switch,
WAP; all in one
Router Network
Hardware Firewalls
■ Protect network from unauthorized access
■ Hardware Firewall
o A device or integrated router
■ Placed between your network & Internet
■ Checks an ACL to permit or deny
■ Still use PC firewall for extra security
Other Devices
■ Patch Panels
o Connects cable runs from
jacks
o Provides connection to
switch or router
■ Repeaters
o Regenerates weak signals
o Used in fiber optic runs
■ Power Over Ethernet (PoE)
o Powering devices over
Ethernet
o GCIT’s VoIP phones
Activity
TEST FOR FIRST HALF
OF CHAPTER
CABLES &
CONNECTORS
7.3
Coaxial Cable
■ Used in old Ethernet & for TV
o Wireless antenna connections
& Cable Internet
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■
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■
Copper conductor & shielding
Thicker cable
F, N, or BNC connector
RG-6 (current cable TV), RG59 (older cable TV), RG-58
(old Ethernet)
o 10Base5 Thicknet
o 10Base2 Thinnet
Coaxial Cable
ADVANTAGES
DISADVANTAGES
■ Very resistant to EMI
■ Thicker than twisted pair
■ Harder to physically
damage
■ Less flexible & harder to
install than twisted pair
■ More expensive to install
■ High speed networking
doesn’t support coax
Review- 4Q
■ What kind of common connectors would be on a
coax cable?
o F or BNC
■ What kind of signal travels on a coax cable?
o Electricity
■ If you have a cable modem, what type of coax cable
do you have?
o RG-6
■ Which cable protects against EMI better, RG-6 or
Cat 5e?
o RG-6
Twisted Pair
■ Pairs of copper wire wrapped in insulation,
twisted around each other
■ Electrical pulses
■ Inexpensive & easy to work with
o Look up a 500ft roll of Cat6 cable
Cables- Twisted-Pair
■ Ethernet
■ 8 wires, 4 pairs
o 1 pair transmit; 1 pair receive
■ UTP
o Most common
o 100m (328ft)
o Interference prone (EMI/RFI)
■ STP
o Each pair is shielded ($$ &
thicker)
o Reduces interference
The Twists
■ Crosstalk
o Small amount of
electricity leaks &
jumps to adjacent
wires
■ No shielding so it
relies on cancellation
o Twisting cancels out
crosstalk
Twisted Pair
ADVANTAGES
DISADVANTAGES
■ Less expensive
■ Thin outer covering
■ Very flexible
■ EMI
– Keep away from
fluorescent lights
■ Easy to run
■ Newer, faster standards
designed to run on
twisted pair
■ Distance limit
■ Possible
eavesdropping
Twisted Pair Category Ratings
Cat Type
Speed (up to) Features
Cat 3
10Mbps
OLD Ethernet & Telephones;
2, 4, or 6-pin RJ11
Cat 5
100Mbps
RJ45
Cat 5e
1000Mbps
RJ45; More twists; better against
EMI/RFI
Cat 6
1000Mbps
RJ45;
Cat 6a
1000Mbps
RJ45;
Cat 7
10Gbps
RJ45;
Twisted Pair Connectors
■ RJ11
o 2, 4 or 6
connectors/wires
o Phone/DSL
■ RJ45
o 8 connectors, 4
pairs of wire
o Ethernet
Review- 5Q
■ Category 6 cables have how many wires in them?
o 8
■ Which connector is used for phone cables?
o RJ11
■ Which connector is used for Ethernet?
o RJ45
■ Why are twisted pair cabling wires twisted?
o To reduce crosstalk
■ When installing twisted pair cabling, what would
you keep it away from?
o Fluorescent lights
Review- 5Q
■ What connector would be on a Cat 5 or 6 cable?
o RJ45
■ What in the ceiling could “mess up” the electrical signal
in an UTP cable?
o Fluorescent lights, electrical boxes/equipment
■ An electrical motor near a UTP cable causes what kind
of interference?
o EMI
■ Signals from one cable jump into another. What
problem is this?
o Crosstalk
■ What is the solution to prevent crosstalk on UTP?
o Twisting of the pairs
Types of UTP Cables
■ Straight-through
o Host to device (hub, switch, router)
o We’re going to make them
■ Crossover
o PC to PC or Device to Device
o We’re going to make them
Making UTP cables
■ TIA/EIA 568A & 568B
Straight-Through Cable
■ 568B to 568B
■ Connect unlike devices
o Computer to Hub/Switch
o Switch to router port
■ On the PC NIC
o Pins 1 & 2 transmit
o Pins 3 & 6 receive
Straight-Through cable
■ Straight-through
■ 568B to 568B
■
■
■
■
■
■
■
■
White-Orange
Orange
White-Green
Blue
White-Blue
Green
White-Brown
Brown
Crossover Cable
■ 568A to 568B
■ Like Devices
o
o
o
o
Switch/hub port to switch/hub port
Router port to router port
PC to router port
PC to PC
Crossover Cable
■ Crossover
■ 568B to 568A
■ Change Oranges & Greens on
ONE SIDE!
■
■
■
■
■
■
■
■
White-Green
Green
White-Orange
Blue
White-Blue
Orange
White-Brown
Brown
Review- 3Q
■ What is the 568B color order?
o Wor/Or, WGr/Bl, WBl/Gr, WBr/Br
■ For speeds of 1000Mbps or more, what Category
cable should be used?
o Cat 6
■ What cable…
o Goes between same devices?
■ Crossover
o Goes from PC to switch?
■ Straight through
o Goes from serial to console port?
■ Rollover
Review- 3Q
■ What colors do you change for a crossover
cable?
o Oranges & greens
■ What pairs transmit?
o 1&2
■ What pairs receive?
o 3&6
Activity
■ Make a Straight-through cable
■ Make a Crossover cable
■ 7.3.2.7 Packet Tracer Lab- Cable a Simple
Network
FIBER OPTIC CABLE
Fiber Optic Cable
■ Transmits pulses of light
o Laser or LED
■ Glass or plastic core
■ No EMI/RFI; no lightning
attraction
■ Used for high speed &
long distance
o LAN backbone
o Connect ISP to Internet
■ 2 fibers cables used
o Transmit & receive
Fiber Optic Cable
ADVANTAGES
DISADVANTAGES
■ Resistant to EMI
■ Very expensive
■ No way to eavesdrop on
the signal
■ Used in backbone
■ Fast speeds
■ Fragile cable
■ Difficult to attach
connector to cable
Types of Fiber Cables
■ Multimode (MMF)
o LED
o Many paths of light (thick)
o Used in LANs/Campuses
■ 2000 meters
o Less $, used more
■ Single Mode (SMF)
o Laser light
o Single path of light
o Very long distance runs
■ 3000 meters
o More $, faster speed
Fiber Connectors
Activity- Use LOW or HIGH
Issue
Bandwidth
Distance
Immunity to EMI/RFI
Immunity to Electrical
Hazards
Media/Connector cost
Installation Skill/Cost
Safety Precautions
UTP
Fiber Optic
Activity
Review- 3Q
■ Which cable is more expensive, copper or fiber?
o Fiber
■ Which cable allows data to travel further,
copper or fiber?
o Fiber
■ Why are two strands of fiber used for
communication?
o Light can only travel in one direction at a time. This
will allow for full-duplex.
Review- 3Q
■ What signal travel on a single-mode cable?
o Laser
■ Which cable would be used to go further
distances?
o Single mode
■ Why would you use fiber between buildings
rather than copper?
o Fiber does not attract lightning
NETWORK
ADDRESSING
7.4.1
MAC Addresses
■ NIC has a MAC address
o Burned onto card; unique;
PHYSICAL
o ID’s your physical PC
■ Like your fingerprint
■ ID’s you permanently
o Attaches FRAME to packet
for NIC to identify
o 48 bits long
IP Address
■ IP identifies where a
host is on network
o Location to find you;
mailing address
o Each MUST be unique;
LOGICAL
o Must have to
communicate
o IPv4: 32 bits long
o IPv6: 128 bits long
What Is Your MAC & IP?
IPv4 Address
■ 32 bits
o Four octets of 8 bits
o Network & host portion
of address
o Routers read network
portion only
■ To send to correct
network
■ 192.168.2.16
o Network is 192.168.2
o .16 is the host portion
IPv4 Address Classes
Class
1st Octet
Range
Default Subnet Mask
Network/ Host # of Hosts per
Portions
Network
A
1-126
255.0.0.0
N.H.H.H
16 million
B
128-191
255.255.0.0
N.N.H.H
65,000
C
192-223
255.255.255.0
N.N.N.H
254
D
E
D: 224-239 Is used for multicasting, webcasts, streaming
video
E: 240-255 Is used research only
Activity
■ Handout
o ID the class of each address
o ID the default SM
IPv6
■ 128 bits
o 8 sets (hextets) of four hex digits
■ Ridiculous amounts of addresses
o Every device can have unique address
o Eliminates IP conservation
■ Written in hex separated by :
o FE22:00FF:002D:0000:0000:0000:3012:CCE3
IPv6 Shorthand #1
■ Rule 1: omit leading zeros
■ Remove zeros before other hex digits
o 00FF can be FF
o 0000 can be 0
■ What can this be reduced down to?

FE22:00FF:002D:0000:0000:0000:3012:CCE3
IPv6 Shorthand #2
■ Rule 2: omit all zero hextets
■ Use :: for multiple zero-value fields

FE22:00FF:002D:0000:0000:0000:3012:CCE3
o FE22:FF:2D::3012:CCE3
■ Can only do this once within address
o Can’t tell how many fields it represents
■ 2001:0:0:34D0:0:0:9F77:2854 CAN NOT be…
o 2001::34D0::9F77:2854
o More examples next slide 
Omit Zero Segments
■ Incorrect address:
o 2001:0DB8::ABCD::1234
■ What could it be???
o
o
o
o
2001:0DB8::ABCD:0000:0000:1234
2001:0DB8::ABCD:0000:0000:0000:1234
2001:0DB8:0000:ABCD::1234
2001:0DB8:0000:0000:ABCD::1234
Activity
■ Examples:
■ Handout
o Reduce the IPv6 addresses to short form
Overview of
IPv4 & IPv6
11:56
TCP/IP
Addressing
6:48
Static Addressing
■ When admin
manually enters IP
addressing info into
each PC
o Only for small
networks
■ Add IP, SM, DG
o DG: Way out your
network (router port)
Setting a Static IP Address
Dynamic Addressing- DHCP
■ Dynamically assigns
IP addresses to hosts
o DHCP Server
manages the
process
o Has a list to give out
addresses for a time
period
■ After time expires, it
goes back into list to
give out
o Gives out: IP, SM,
Default Gateway,
DNS
Can’t Communicate with DHCP
Server?
■ Windows gives PC an APIPA address
o
o
o
o
Automatic Private IP Addressing (APIPA)
169.254.0.0 to 169.254.255.255
You won’t be able to communicate
Every 5 min. it tries to talk to DHCP for real address
ICMP
■ Sends control message for troubleshooting
■ PING
o
o
o
o
Command line test for connectivity
Ping an IP address
Echo request/reply 4x default
Ping a website to get the IP address
Ipconfig or ipconfig /all
Activity
■ Lab 7.4.1.11- Configure a NIC to use DHCP
■ Packet Tracer Lab 7.4.1.12- Add Computers to
an Existing Network
TRANSPORT LAYER
PROTOCOLS
7.4.2
Role of Transport Layer
■ Establishes communication between
applications & delivery the data
Transport Layer Features
■ Keeps track of
conversations
o Makes sure they go to
correct applications
■ Segments &
reassembles data
■ Identifies target
application with port
number
TCP or UDP
■ All protocols fit into TCP or UDP for rules
■ TCP
o Connection-oriented, numbering segments,
acknowledgements, reliable delivery, error detection,
retransmission
o Email & web browser
■ UDP
o Connectionless, best-effort delivery, simple, low
overhead/faster
o DNS, DHCP, TFTP, NFS
Protocols
Protocol
■ Set
TCP/IP
#
Information
ofPort
rules
for
communication
N/A
Rules to transmit data
80
Connection to transfer web pages (TCP)
HTTPS
443
Secure connection for web pages transmission (TCP)
FTP
20/21
File transfer (TCP)
Telnet
23
Remote login (TCP)
SSH
22
Secure remote login (TCP)
POP3
110
Transfer of email from email server to you
IMAP
143
Transfer of email from email server to you
SMTP
25
Used to send email between email servers
DNS
53
Name to IP Address translation (UDP)
DHCP
67/68
Assigning IP Addresses (UDP)
RDP
3389
Remote Desktop Application (UDP/TCP)
HTTP
o Common Protocols used in communications
Activity 1 of 4
Activity 2 of 4
Activity 3 of 4
Activity 4 of 4
■ Identify the Protocol & Port # Review Handout
Review- 3Q
■ Which protocol is used for web page transmission
on port 80?
o HTTP
■ Which command will display a computer’s IP
address?
o Ipconfig
■ You have a network of 100 devices. Which process
will easily allow all computers to automatically be
able to communicate on a network by assigning IP
addresses?
o DHCP
Review- 4Q
■ Your computer has an IP address of
169.254.1.1. What does this mean to you?
o It did not get an IP from the DHCP server
■ Which class address is 201.17.55.9?
o C
■ Which utility can test connectivity?
o Ping
■ Which protocol allows remote login, but is not
secure?
o Telnet
PC SUPPORT &
REPAIR
Chapter 7
Networking Concepts