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TRANSCRIPT
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Agenda
Introduction to Networking
Why Networking
Components
Topology
Network Types
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Networking: What & Why?
Networking :connect dispersed resources: people, computers, sites, nodes, offices, information
bases, databases etc.
People Network develops via contacts
Rail/ Airline Network links train stations/ airports
Computer Network links computers e.g. PCs
PURPOSE: collect, organize, protect, share, disseminate anduse INFORMATION on resources, for better business
operations E.g. Install/configure software on servers/ clients
Monitor/ control access; backup/restore
Critical Business Tool
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Networks of Computers
Computing nodes (PCs, Minis, Mainframes) Data Server node
Processing/ Application/ Web Server node
Client node
Network node
Network links can span distances at 3 levels: LAN: Local Area Network (building or campus)
MAN: Locality or City-wide network
WAN: Across country or continent(s)
Each technology has its own distance or size constraint Speed or reliability is assured only within those limits:
Signal Propagation
Signal Attenuation
Signal Bounce
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Effectiveness
All businesses need to work at high speed
Good Decisions need secure, accurate and timely
information internal & external
Messages from a Sender must reach Receiver with
following qualities:
Availability
Reliable Accuracy
Appropriate Timeliness
Integrity/ Uncorrupted
Confidentiality
Authenticated Source
Basic Networking
Secure Networking
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Agenda
Introduction to Networking
Why Networking
Components Node Types
Network Types
Topology
Network Types
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Nodes - Providers or Consumers
Pure Consumers Clients
WinME
Pure Providers Servers
WinNT Server 4.0, Novell NetWare
Hybrids Peers
WinXP, Win95, MacOS Sender ReceiverMedium
Protocol
Message Message
Components of Communication System
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Network Types
Server Based (Client-Server)
Servers provide shared services
Clients find required resources and request services
Peer Network
Workgroups; no central security
Hybrid Network
Have all types of Nodes, along with domains and
workgroups
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Server Based Network
Also called Client-Server Servers: share secure services (files, DB, printer)
Run a NOS e.g. Novell NetWare, RedHat Enterprise Linux
Pros:
Central sharing of applications, hardware, files User-friendly, managed security (rules/ policies)
E.g. Windows Server 2003 Domains with Active Directory
Optimized/specialized servers are more efficient
Cons: Expensive HW, NOS, Licenses
Server failure renders a network unusable.
Need dedicated Administrator(s).
Dedicated HW and specialized SW add to the cost.
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Peer Network
Workgroups
Ad hoc; no central security/ login
Resource sharing controlled by users
Protected by separate passwords Unprotected (no password)
accessible from any node
Pros:
Easy/cheap to install/ setup; Good for
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Hybrid Network
Combined features (most modern enterprise LANs)
Have all types of Nodes, along with domains and workgroups
Servers provide shared application, authentication, email, backup
and license services
Selective sharing of folders and resources (printers, files, ftp,databases) to limited groups of colleagues (peer-to-peer or
workgroup-based)
PRO: Best of both worlds
CON: Shared resources on Peer nodes are at risk onsecurity, backup and performance concerns
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Server Types
These need HW in tune with user load :
Application Server
Directory Server (Domain Controller ) Fax Server
File and Print Server
Database Server
Mail Server (Microsoft Exchange server of 2000/2003) Web Server
Communication Server
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Eligibility to be a Server
Faster CPUs
More memory
Larger disk drives
Extra peripherals
Most importantly, server OS which are designed to handle
multiple requests for shared resources expediously.
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Windows Server 2008
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Component Requirement
Processor Minimum: 1 GHz (x86 processor) or 1.4 GHz (x64 processor)
Recommended: 2 GHz or fasterNote: An Intel Itanium 2 processor is required for Windows Server
2008 for Itanium-Based Systems.
Memory Minimum: 512 MB RAM
Recommended: 2 GB RAM or greater
Maximum (32-bit systems): 4 GB (Standard) or 64 GB (Enterprise
and Datacenter) Maximum (64-bit systems): 32 GB (Standard) or 1 TB (Enterprise
and Datacenter) or 2 TB (Itanium-Based Systems)
Available Disk Space Minimum: 10 GB
Recommended: 40 GB or greater
Note: Computers with more than 16 GB of RAM will require more
disk space for paging, hibernation, and dump files.
Drive DVD-ROM drive
Display and
Peripherals
Super VGA (800 x 600) or higher-resolution monitor
Keyboard
Microsoft Mouse or compatible pointing device
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Selecting Type of NetworkAre ALL of these TRUE:
a. # Users expected < 8
b. Distances small; single LAN segment
c. No specialized servers or control
d. Limited budgetNOYES
Server BasedPeer-to-Peer
MAN Links WAN Links
Multiple
Sites? Across CitiesIn a city
NO
No MAN/WAN Links
Is ANY of these TRUE:
a. # Nodes expected > 100
b. Certain groups need security barrier
c. Spans not confined in floors or buildings
LAN Internetworking
YESNO
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Exercise
A company operates its two branches, one in Bangalore and
other in Chandigarh. The company wants the two locations to
share a single database so that managers at each facility can
exchange work orders and monitor inventory on demand.
Users need some control over resources, but the companyalso wants network faxing and dial-up services at each
location.
Would you choose a peer-to-peer network or server basednetwork, or a combination of both? Why?
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Agenda
Introduction to Networking
Why Networking
Components Topology
Network Types
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Topology
Physical Layout of nodes, media and resources (cabling,access points, towers)
Logical Layout path taken by the signal/ data elements
Topology affects the performance and security parameter
Topology affects decisions like type of equipment to purchase
and best approach to NW management
Simple to complex:
Pt-to-Pt (e.g. hotline)
Linear Bus
Ring
Star
Others (Switched, Extended Star, Mesh, Hybrid)
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Linear Bus
Easy to install/ maintain (
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Logical Bus
The logical topology on a Physical Bus
Can also be used on Physical Star
Nodes are Passive(listening, not forwarding signals)
FCFS scheduling of transmitters
Obsolete due to performance and reliability
concerns A nodes signal reaches all other nodes (e.g.
via Hub); only the addressee responds
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Ring Topology
Active: nodes retransmit signals
SPOF avoided by dual rings
FDDI, SONET are physical rings
Token Ring (logical) runs on PhysicalStar
Fair sharing; no monopolyUse: hi-traffic, time-critical apps as nocomputer can monopolize thenetwork.
Any Node or Link is a SPOF
Nodes linked in a Ring no collisions or terminators
Data runs clockwise/ counterclockwise
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Star Topology
All nodes link to a central hub, switch,concentrator
Uses more cable
Hub can be a SPOF
Common in home, SME LANs
Physical Star is popular choice to
support Logical Bus/Ring
Even if one link or node fails, rest ofnetwork functions fully
Hub or Switch is a SPOF;
But no Node or Link is.
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Extended Star
All nodes link to a sub-central device, which inturn connects to a central unit
Suitable for larger LANs and MANs to preventdegraded signals
Multiple POF; but partial impact Common in enterprise/ campus LANs
Usually supports switched signaling
Even if one link or node fails, rest of network
functions fully
Any Hub or Switch is a POF;
But no Node or Link can halt
entire network.
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Mesh Topology
Adds links for Fault-tolerant operation Messages can take any of several possible paths
from source to destination
FULL: Redundant links to all devices Most expensive
common in WANs, core cross-country networkoperator backbones
PARTIAL: only a few alternate routes, forcritical nodes common in large enterprise and service provider
metro backbones
E.g. Internet
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Hierarchical (Tree) Topology
Integrates multiple stars onto a ROOT. (Bus/star hybrid ) Simple form: Only hub devices connect directly to the tree
bus, and each hub functions as the "root" of a tree of devices.
Supports future expandability much better than a bus (limited
number of devices due to the broadcast traffic) or a star (limited by thenumber of hub connection points) alone.
ROOT can be a SPOF
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Common Logical Topologies
Physical Star can be used to implement:
Logical Bus (Star Bus) Nodes signal is retransmitted by hub to all
other nodes; only the addressee responds
One transmitter at a time; FCFS
Smart hub can remove a faulty node fromnetwork
Logical Ring (Star Ring) Uses Concentrator or MSAU
A logical token circulates sequentially to allnodes
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Wireless Networks
First wireless voice transmission (1915) in US
Wireless telephony Analog (1970s) started in Nordic countries
Digital (1984+) in Europe (standards) and US (no standards)
Usual Topologies in data networks: Point-to-Point (ad-hoc)
Star (Access point)
Extended Star