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Slide 1
LAN Review
Slide 2
What is a Network? A group of computers and devices connected
together for the purpose of sharing resources and services
Slide 3
What is a LAN?LAN A group of computers in a single location
where all cabling belongs to the company
Slide 4
What is a WAN?WAN Two or more LANs connected together using a
telecommunication service (WAN Link) such as T1, Frame Relay, DSL,
PSTN etc.
Slide 5
What is a WLANWLAN This is a LAN that uses Radio Frequency
technology to allow for communication among computers and
devices
Slide 6
Role of Computers in a Network Client- computer or device that
specializes in knowing how to ask for services in a network.
Example: Workstation in a network Server- Computer or device that
specializes in knowing how to provide services in network. Example:
Print Server in a network Peer- Computer or device that may be able
to be both a server or a client at the same time. Example:
Workstation in a simple network (peer-to-peer network)
Slide 7
What is the Network Medium? Cabled/Wired o UTP (cat 5, 5E, 6,
7) o Coaxial o Fiber Optic (single mode, Multi mode) Wireless o
Radio o Microwave o Infrared
Slide 8
What are ProtocolsProtocols Set of rules that allows computer
to communicate with each other
Slide 9
Network Protocols TCP/IP Nwlink or IPX/SPX NetBEUI
Slide 10
Network Software NOS o Windows Server 2008 o Windows Server
2003 o Windows 2000 Server o Windows NT o Novell Netware 6.5 o Unix
o Linux
Slide 11
Network Services The reason for setting up a network in the
first place: File and Print DHCP (Dynamic Host Configuration
Protocol) DNS (Domain Naming Service) Security E-mail Application
or Database Web / Proxy Mail/FTP/IM/Chat RAS (Remote Access
Service)
Slide 12
Network Types Peer to peer Client/server
Slide 13
Advantages of Peer-to-Peer Easy to install and configure o Most
Client OS already have the components required to set the computer
as part of a peer to peer network Individual machines do not depend
on the presence of a dedicated server Individual users control
their own shared resources Inexpensive to purchase and operate Need
no additional equipment or software beyond a suitable operating
system. Best for networks with less than 10 users
Slide 14
Disadvantages of Peer-to-Peer Security applies to a single
resource at a time Users may be required to use as many passwords
as there are shared resources. Each machine must be backed up
individually to protect all shared data. The machine that shares
resources suffers reduced performance There is no centralized
organizational scheme to locate or control access to data
Slide 15
Advantages of Client/Server Centralized User Accounts,
Security, and access controls simplify network administration More
powerful equipment means more efficient access to network resources
A single password for network logon delivers access to all
resources Server based networking makes the most sense for networks
with 10 or more users or any network where resources are used
heavily.
Slide 16
Disadvantages of Client/Server Server failure renders the
network unusable, or it results in loss of network resources.
Special purpose server software requires allocation of expert
staff, which increases expenses. Dedicate hardware and software add
to the cost.
Slide 17
What are Topologies?Topologies The physical shape computers and
devices create when connected together The different topologies
are: BUS STAR Ring Mesh Hybrids
Slide 18
Topologies Bus (not commonly found in LANs anymore) o needs
termination (signal bounce) o Adding devices disrupts the network o
Cable failure hard to find Star (Most common topology) o Requires a
hub/switch o Easy to troubleshoot o Requires more wiring
Slide 19
Topologies Ring o No beginning and no end o Uses token passing
o Active topology (regenerates signal from device to device) Mesh o
More Fault tolerant
Slide 20
Variation of Major Topologies (Hybrids) Star-Bus o Backbone
interconnect two or more hubs Star-Ring o Physical Star, but
logical ring o The way the IBM token ring Works.
Slide 21
What are Networking Models? A model describes the different
stages data needs to go through in order to go from one computer to
another. Examples are TCP/IP and the OSI models
Slide 22
OSI Networking Model 7 Layers o Application email o
Presentation message is compressed and encrypted o Session tells
the other side the message is coming o Transport breaks up into
packets and gives each a sequencing # TCP o Network o Data link mac
address o Physical set of rules that tells how things will be
transmitted
Slide 23
IEEE 802.X This standard describes the different technologies
(architectures) used to connect computers together. The
specifications covered in the Data link layer in the OSI model are
too broad and can be subdivided into Logical Link Control Media
Access Control (MAC)
Slide 24
IEEE 802.X Standards of interest to us 802.3 Ethernet Networks
802.11 Wireless Networks 802.15 Wireless PAN (Blue Tooth)
Slide 25
TCPI/IP Networking model 4 layers o Application Layer o
Transport o Internet Layer o Network Interface Layer
Slide 26
TCP/IP Protocols Application layer o Telnet, FTP, HTTP, SMTP o
DHCP, DNS, TFTP, SNMP Transport Layer o TCP, UDP Internet Layer o
ICMP, ARP, RARP, IP
Slide 27
Computer/device ID/Addressing Every computer or device which is
part of a TCP/IP network includes a network card. Every network
card needs to have: Physical address (MAC address)MAC address
Logical address (IP address)IP address
Slide 28
IPV4 (IP Version 4)Addressing Supports 4.3 billion addresses 32
bit address (Dotted decimal notation). 32 Zeros and Ones 4 octets
of 8 bits (8+8+8+8=32) The addresses are divided into Class A, B,
C, D, E according to network size. Private vs. Public Addresses.
(Private addresses are only valid in a private network not the
Internet. Public are valid in the Internet) o Ex. Private address.
10.0.0.0/8, 172.16.0.0 to 172.31.0.0, and 192.168.0.0/24
Slide 29
IPV6 Addressing 128 bit address Supports 3.410 38 addresses The
U.S. Government has specified that all federal agencies must deploy
IPv6 by 2008. Normally written as eight groups of four hexadecimal
digits. For example, 2001:0db8:85a3:08d3:1319:8a2e:0370:7334.
Slide 30
Communication types Unicast (One to one) Broadcast (One to all)
Multicast (One to a group)
Slide 31
IP address Class A First Octet starts with binary 0 First octet
represents Network ID (0-127) Next three octets represent hosts (16
million) Example: 80.28.29.205
Slide 32
IP address Class B First octet starts with binary10 (128-191)
First and second octet represent network ID Third and fourth octet
represent hosts (65,534 hosts) Example: 145.23.89.60
Slide 33
IP address Class C First octet starts with binary 110 (192-223)
First, second and third octet represent network ID. The last Octet
represents the host ID. Class C networks have 254 hosts Example:
197.45.67.87
Slide 34
IP Address Class D First octet starts with binary 1110
(224-239) Used for multicasting
Slide 35
IP address Class E First octet starts with 11110 (240-255)
Reserved for experimental use and cannot be used for address
assignment
Slide 36
Subnet Mask The subnet mask represents the number of bits in
the IP address that identify the network address. The sending
computer needs to know this in order to decide whether the packet
is meant for the local network or for another network. Default
Subnet masks are: Class A 255.0.0.0 o 11111111 00000000 00000000
00000000 Class B 255.255.0.0 o 11111111 11111111 00000000 00000000
Class C 255.255.255.0 o 11111111 11111111 11111111 00000000
Slide 37
Binary to decimal conversion Binary= 01001011 This is
equivalent to Decimal=64+8+2+1=75 1286432168421 01001011