CHAPTER
Introduction to LANs
MODULE
Purpose and Use of a Network
Definition of a Network
• Composed of computing and information
devices connected together
–
–
–
–
–
clients
servers
shared printers
other shared devices
internetworking devices
• link to the external world
– Etc.
Purpose
• Access and share local resources and
information
– Hard and soft resources
• Access and share global resources and
information
– Internet resources
• Messaging, Collaboration etc.
A Note on Sharing and
Collaboration
• Sharing
– One shares the application
– The other watches the changes being made
• Collaboration
– Both share the applications and both can
make the changes
Network Types
• Locally oriented (LAN)
• Globally oriented (WAN)
• A combination of the above two types
A Simple Network
Printer
Client
Server
Client
Peripheral
Device
(Modem)
Directly attached
peripheral (Network
Printer)
Appliances
• Network appliance
– Network Attached Storage (NAS)
– Network Printer
• Internet appliance
NAS
• NAS can be directly attached to
network (switch, for example)
• NAS components
– Processor
– Embedded OS (Eg: Embedded Linux)
– Embedded software (Eg: SAMBA Server)
Sample Components of a
Simple Network
• Network Hardware
• Network Software
• Resources
– Hard resources
– Soft resources
• Personnel
– Administrators
– Users
Hardware
• Servers
• Clients
• Peripheral devices
– Network printers
– NAS
• Media (Cabling)
– Twisted pair, coaxial cable, optical fiber etc.
– Wireless networks without cables
• Networking Devices
– Hubs, switches, routers
Media
• CAT 5
– 100 Mbps LANs
• CAT 5e
– 1000 Mbps LANs
• CAT 6
Internetworking Devices
• Hub
– Simply shares the electrical connection
• Switch
– Switches the data packet based on MAC address
• Bridge
• Router
– Routes the data packet based on the IP address
Software
• Network operating system
– Windows 2003 Server, Windows Server
2000, Linux etc.
• Client operating system
– Windows XP, Windows 2000, Linux etc.
• Various application server operating
systems
– SQL server, Web server, FTP server etc.
Resources
• Hard resources
– Printers, scanners etc.
• Soft resources
– Folder, application etc.
Hard Resource Sharing Example
Printer
(Attached directly or to the Server)
Print Queue
Print Jobs
Print Jobs
Print Server
Soft Resource Sharing (File
Server) Example
Administrator
User
Server Tariff
Resource
(Folder to be
shared).
Client
Client
User
User
Application Server Example
Database
Administrator
Server with SQL
engine and database.
User
Client
User
Sharing of
SQL engine based
application.
Client
User
Messaging Example
Remote
Client
Internet
E-mail
Internet Gateway
Messaging
Server
Administrator
Client
E-mail
User
Personnel
– Administrators
• Administrator, account operator, server
backup operators etc.
– Users
• Local user, power user, global user etc.
Network Administrator's
Responsibilities
• Install, manage and fine-tune the
network resources
• Create and manage users
• Assign privileges to users to use the
resources
– Sharing resources
– Accessing network applications
• Ensure LAN security
Users
• Global users
• Local users
• Group of users
• Power users
• Users with administrative privileges
Earlier Windows Servers
• Windows NT
– Windows NT Workstation, Windows NT
Server, Windows NT Enterprise Server
• Windows 2000
–
–
–
–
Windows 2000 Professional
Windows 2000 Server
Windows 2000 Advanced Server
Windows 2000 Data Center Server
Windows 2003 Server Versions
• Web Edition
• Standard Edition
• Enterprise Edition
• Datacenter Edition
Network (Services) Servers
•
•
•
•
•
DHCP (Services) Server
DNS (Services) Server
Proxy (Services) Sever
WINs (Services) server
RAS (Services) Server
– Routing and Remote Access Server
• VPN (Services) Server
• Share Point services
Application Servers
• SQL Server
• Web (Service) Server
• Media (Service) Server
Major Network Architectures
• .Net
• J2EE
Web Research Areas
• Directly attached network peripherals
– Network printer, Network stand-alone
hard drives (Snap)
– Network appliance and a web appliance
• Variations of the Windows Server 2003
operating system
• What is the .Net architecture ?
Key Words
• Hard and soft resources
• Client operating systems
– Windows 9x, Windows NT, Windows 2000
Professional, Windows XP, Linux, OS/2,
Mac OS X
• Server operating systems
– Windows NT Server, Windows 2000
Server, Windows 2003, Novell NetWare,
Unix, Linux, OS/2 Warp
Further Keywords
• Sharing of printers
– local printer
– shared printer
– network printer
• Symmetric Multi Processing (SMP)
• Clustering
– Load balancing
END OF MODULE
END OF CHAPTER