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8/3/2019 Introduction Computer Networking(1)
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Introduction to
Networks
Networking Concepts
IST-200
VWCC
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What is Networking?
Connecting computers
to form a
Local Area Network
( LAN )
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Device Sharing
Sharing of:
HardwareSoftware
Information
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A Simple Network
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Local & Wide Area
NetworksEarly networks were custom builtConnecting a dozen computers
Only 1 or 2 peripherals
Early Ethernet
30 users total span of 601 feet
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Local Area Network
(LAN)A single collection of machines &peripherals
Generally less than 1000 computers
Spanned generally less than 250meters feet
Basic building block for largernetworks-Internetworks
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InterNetworks
IntraNetworksA network of networks
A networked collection of LANsMore than one floor in abusiness (intranetwork)
Multiple buildingsCampus environment
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Wide Area Networks
(WAN)Spans miles of distance
Two or more separate locationsDown the road or across the
world
Microsoft, Federal Express
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The Internet
A WAN internetwork
Millions of machines worldwide
The World Wide Web (WWW)
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Networking
TerminologyClient/Server relationship
Client requests sharedresources
Server responds & shares
resources
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Networking
Terminology
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Client Server
NetworksConcentrate CPU power & storage
capacityWindows NT Server / Server 2000
Peer to Peer
Client/Server role interchanges
Windows 95/98/2000/XP
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Simple Network Needs
Medium to carry data
Adapter (NIC)
Protocol
Client / Server Software
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Local Network
Medium (media)Carries network messages
Connects machines together onnetwork
Four types: Metallic cable coaxial - dated
Twisted pair
Fiber optic cable
Wireless
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Network Interface
Card(NIC)
Physical link between machine& network
Connection between machine &
medium
Also known as network adapter
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Network Protocols
Common set of communication rules
Identify oneself & others on network
Interpret signals
Begin & end network communication
Manage network information exchange
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Protocol Examples
TCP/IP
for the Internet
IPX/SPX & NWLINK
for Novell
NetBEUI for Microsoft
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Network Software
Programs that access the network
Network Operating System (NOS)
Windows NT
Novell NetWare (IntranetWare)
Consist of client & servercomponents
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Network LayersNetwork Applications ( NOS &client)
Instruct network mediumUsing machines interface (NIC)
Address & exchange information
To other machines on LAN or WAN
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Layers of the
Network
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Network TypesPeer to Peer
Windows 98/2000
Windows for WorkgroupsClient Server (server-based)
Windows NT
NovellUnix / Linux
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Peer to PeerNo centralized controlAct as both client & server
User controls access to machine
Institutionalized chaos & securityconcerns
Adding machines slows networkdown
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Peer to Peer
DisadvantagesSecurity for only a single resourceat a time
Users may need to know manypasswords
Individual machine backups
Speed decreases while sharingNo central location/access of data
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Server Based
NetworksServer is the key to this type
Centralized control of resourcesUtilize faster processors
More memory
Extra peripherals
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Server Security
Physical access to the server
Specialized sentry servers
Domain model
Account names
PasswordsFirewalls
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Server Based
AdvantagesCentral security/ accounts/ access
Simplify network administration
Powerful/ efficient access to
resources
Single password for each userBest for high use, user, networks
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Server Based
DisadvantagesServer failure results in unusable network
Server failure results in loss of resourcesExpert staff to manage increases cost
Dedicated hardware increases cost
Dedicated software increases cost
All disadvantages may be overcome
with $$$
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Server Hardware
Requirements
High Speed DrivesMirrored or
RAID
512 MB Memory Minimum
High Quality NIC(s)
High-end Processor(s)
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Specialized Servers
Individual services supplied
Application Servers
Communication Servers
Domain Controllers/Directory
ServersFax Servers
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Specialized Servers
(cont.)Mail Servers
Web ServersFile & Print Servers
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Communication
ServersAccess beyond networks local scope
Inbound & outbound resource access
Dial in via modem
Windows NT server Remote Access
Server(RAS) manages dial in networkconnections
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Domain Controllers/
Directory ServersLocate, store, & secure informationabout network
Allows computers, users, groups, &resources to be combined intodomains
Domain access allows single loginto all allowed resources
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File and Print Servers
File storage & File retrieval
Access to network printersApplications run locally
Store data on server
Window NT server is capable
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Web Servers
World Wide Web (WWW)
File Transfer Protocol (FTP)
Gopher services
Intranets
NT Server Internet InformationServer (IIS)
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Selecting the Right
NetworkBudget considerations, number ofusers?
Physical span of the network?
Specialized servers, services desired?
Internetwork or WAN access?Future growth?
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Summary
Basic elements to build a network
Medium, physical interface, protocol
Networking software-client & server
Basic network types
Peer to PeerServer based
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