Lesson 3 – UNDERSTANDING NETWORKING
Lesson 3 – UNDERSTANDING NETWORKING. Network relationship types Network features OSI Networking model Network hardware components OVERVIEW.
Dec 20, 2015
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Lesson 3 – UNDERSTANDING NETWORKING
Network relationship types
Network features
OSI Networking model
Network hardware components
OVERVIEW
Peer-to-peer
Client / server
NETWORK RELATIONSHIP TYPES
Computers on the Network communicate with each other as
equals.
Peer-to-peer relationships
Each computer:
Shares resources.
Sets up and maintains security.
Accesses Network resources.
Peer-to-peer relationships
Peer-to-peer relationships
A distinction exists between computers that make available
Network resources and computers that use those
resources.
Client / server relationships
Resources are centrally managed and hosted.
Client computers do not share resources with other client
computers / servers.
Server computers make available, manage, and administer
shared resources.
Client / server relationships
Client / server relationships
Use less expensive hardware.
Easy to administer.
No NOS required.
More built-in redundancy.
Pros for Peer-to-peer Networks
May hurt user’s performance.
Not very secure.
Hard to back up.
Cons for Peer-to-peer Networks
Very secure.
Better performance.
Centralized back up.
Very reliable.
Pros for Client / server Networks
Require professional administration.
More hardware intensive.
Cons for Client / server Networks
File sharing
Printer sharing
Application services
Remote Access
Wide Area Network
Internet and intranet
Network security
NETWORK FEATURES
Originally, the primary reason to have a Network.
Provides central storage for common documents,
databases, and work files.
Requires a shared directory or disk drive.
Incorporates File Locking.
File sharing
Most common ways of sharing printers are:
Printer queues.
Workstations that access printers directly.
Printer sharing
Printer server function can be filled by:
A fileserver with the printer connected to it.
A computer connected to the Network, with the printer
connected to the computer.
An in-built print server on a printer’s NIC.
A dedicated Network print server.
Printer sharing
Advantages:
Reduces disk space needed.
Easier to administer the application.
Application services
E-mail systems are divided into:
File-based.
Client / server.
File-based e-mail system:
Consists of a set of files kept in a shared location on a
server.
Client / server based e-mail system:
Contains messages and handles e-mail
interconnections, inside and outside the company.
Users use this feature to access files and e-mail from a
remote location, such as their homes.
Remote Access
Methods:
Set up Remote Access Service (RAS) connection on a Windows
NT server.
Use a dedicated RAS.
Employ a workstation on the Network.
Set up a Virtual Private Network (VPN).
Install Windows Terminal Server or Citrix MetaFrame.
Remote Access
WAN is the connection of multiple Local Area Networks
(LANs).
It is created when users of one LAN need frequent access to
the resources on another LAN.
Wide Area Network
An Internet connection for a Network consists of a
telecommunications network connection to an Internet
Service Provider (ISP).
Internet and intranet
Network components :
Leased 56KB line
ISDN line, or a fractional or full DS1 (T-1) connection
Channel Service Unit / Data Service Unit (CSU/DSU)
Router
Firewall
Web server
Internet and intranet
This internally focused Network:
Mimics the Internet.
May also host Internet-type services like FTP servers.
Is not usually accessible from outside the LAN.
Internet and Intranet
Provided by:
Features of the NOS.
Physical cabling plant.
The Network’s connection with other Networks.
Client workstations.
Actions of the users.
Security policies.
Etc.
Network security
Conceptual model.
Used in Network design and engineering Network solutions.
Defines methods and protocols needed to connect one
computer to another.
OSI NETWORKING MODEL
The 7 layered OSI Model
7 layers of the OSI Model
Defines the properties of
the physical medium used
to make a Network
connection.
7 layers of the OSI Model
Connection can be either:
Point-to-point
Multipoint
Transmission can be either:
Half-duplex
Full-duplex
7 layers of the OSI Model
Defines standards that
assign meaning to the bits
carried by the physical
layer.
7 layers of the OSI Model
This layer is sub-divided into:
Logical Link Control
Medium Access Control
7 layers of the OSI Model
Defines how data packets get
from one point to another on a
Network and what goes into
each packet.
7 layers of the OSI Model
Manages the flow of
information from one Network
node to another.
7 layers of the OSI Model
Defines the connection from a
user to a Network server or
from a peer on a Network to
another peer.
7 layers of the OSI Model
Takes the data supplied by the
lower-level layers and trans-
forms it so it can be presented
to the system.
7 layers of the OSI Model
Controls how the operating
system and its applications
interact with the Network.
How data travels through the OSI layers
Servers
Hubs, Switches, and Routers
Cabling and Cable Plants
Workstation Hardware
NETWORK HARDWARE COMPONENTS
A server is any computer that performs Network functions for other computers.
Servers
Types of servers:
File server.
Print servers.
Application servers.
E-mail servers.
Networking servers that provide Network services (automatic
assignment of TCP/IP addresses).
Servers
Types of servers:
Routing servers (routing of packets from one Network to
another).
Web servers (encryption/decryption and other security
services).
Virtual Private Network (VPN) servers.
Internet servers.
Remote Access servers.
Servers
Typically run some Network Operating System (NOS) like:
Windows 2000 Server and Advanced Server
Windows NT Server
Novell NetWare
UNIX
Servers
A true server-class computer will have:
Built-in redundancy with multiple power supplies and fans.
High-performance designs.
Monitoring software and hardware.
Servers
A hub (concentrator) connects a number of network cables
to a Network.
Network connections on a hub share a single collision
domain.
Hubs, Switches, and Routers
A typical Network hub
Hubs, Switches, and Routers
A switch makes a Network connection private.
It collects data from each connection and forwards it to a
Network backbone.
Switches connect many hubs to a single backbone.
Hubs, Switches, and Routers
Using switches and hubs in concert
Hubs, Switches, and Routers
A router routes data packets from one Network to another.
Two Networks connect to a router using their own wiring
and connection type.
Hubs, Switches, and Routers
Types of Network cable:
Unshielded Twisted Pair (UTP)
Shielded Twisted Pair (STP)
Coaxial Cable (coax)
Fiber Optic
Cabling and Cable Plants
Any computer on a Network is referred to as a Network
workstation (or Network Client).
Workstation Hardware
Network relationship types:
Peer-to-Peer networks
Client / server Networks
SUMMARY
Network features:
File sharing
Printer sharing
Application services
Remote Access
Wide Area Network
Internet and intranet
Network security
Summary
Open Systems Interconnect (OSI) Networking Model:
Application
Presentation
Session
Transport
Network
Data-link
Physical
Summary
Network Hardware Components:
Server types
Hubs, Switches, and Routers
Summary
Cabling and the Physical Plant:
UTP
STP
Coax
Fiber
Wireless
Summary
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