Introduction to Local Area Networks
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Introduction toLocal Area Networks
ronaldschlager.com © Ronald Schlager
Introduction to Local Area Networks
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Overview
Why Local Area Networks?
Characteristics of LANs
Typical Fields of Application
Communications Characteristics
Environmental Characteristics
Features
Network Topologies
Introduction to Local Area Networks
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Why Local Area Networks?
Local Area Networks are use for information interchange between devices of network users
Network
Introduction to Local Area Networks
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Why Local Area Networks?
Office automation (paperless (?) office)
Common use of mass storage (e.g. harddisks) or printers Direct information exchange between users
Internet access
Telephony integration into networks (Voice over IP)
Video conferencing and video surveillance
Mobilizing of devices and applications
„Virtualization “ of systems (services, elements)
„Cloud Computing“ (services out of the network, out of the „Cloud“)
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Characteristics of LANs - Today
Limited size
Most often private ownership
Often owner managed
No stringent use of certain protocols
Flexible physical and logical structure
High bitrates
Limited use of multimedia applications Practical tip:
1000 Mbps (1 Gbps) in the workgroup is
state of the art
Practical tip: 1000 Mbps (1 Gbps) in the workgroup is
state of the art
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Characteristics of LANs - Tomorrow
Shift of LAN technology into WANs (fluent transition) Users are not the owners of LANs - Outsourcing Outsourcing partners offer external management TCP/IP is common protocol architecture
Fully redundant and reliable physical network structure
Logical structure on demand(depends on intelligence of active network elements)
Bitrate of 1 - 10 Gbps to the desktop computer, 10-100 Gbps the server, 100 Gbps in backbone
Full multimedia support
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Typical Fields of Application
Office communication
Factory automation
Laboratory automation
Building automation
Security technology (e.g. video surveillance)
Mobility (cars, airplanes, ships,...)
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Communications Characteristics
Office LANIndustria LAN
Validity periodof dataYears
Fractions ofseconds
Amounts of dataGiga Bytes -Tera Bytes
BitsBytes
DelaySeconds -Minutes
Fractions ofseconds
Number of networked stationsMany Few
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Environmental Characteristics
Office LAN Industria LAN
Ambient temperature0 - 40oC 0 - 60oC
Electromagnetic interferencelow high
Vibrationsweak
(exception: earthquake)strong
Pollutionlow high
Introduction to Local Area Networks
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Features – Building Blocks of Computers - Example
Personal Computer Hardware
Operating system(e.g.
Microsoft Windows,Linux)
Applicationprogram(s)
(e.g. text processing)
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Features – Building Blocks of Computers - Example
Personal Computer Hardware
Operating system(e.g.
Microsoft Windows,Linux)
Applicationprogram(s)
(e.g. text processing)
System hardware
Motherboard, CPU, memory, power supply,
case, cooling devices
Mass storage
Harddisk, diskettes, CD-ROM, DVD, removable disk drive
System software
System management(hardware, software)
Link betweenapplication software
and hardware
Application software
Word processing, spreadsheet,
database, book keeping,
payroll, warehouse management
email, Web,...
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Features – Building Blocks of Computers - Example
Personal Computer Hardware
Operating system(e.g.
Microsoft Windows,Linux)
Communications system
(e.g. TCP/IP)
Applicationprogram(s)
(e.g. text processing)
Networkinterface
cardCommunications
hardware
Physical interfaces,signal generation,
signal tranmission, reception
Communications software
Interface control,logical communication
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Features – Internal Networking
Server
Hub
Client
Client
Client
Printer
Printer
Centralized management of data (files)
andprint jobs,
centralized data processing
Data input and outputLocal data processing,
Local data storageAdditional service:
Performs local print jobs
Signal distribution,switching of information
betweenstations
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Features – Inter-Site Networking
Example
Router Router
Wide Area Network(WAN)
RoutingLine backup
Least cost routingInterface adoption
Security
Transfers information across large distances
Example: Internet
LAN
ClientClient
Client
Server in head office
LAN
ClientClient
Server inbranch office
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Example
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LAN
Features – Internet Access
Router
Internet
Firewall
Web Server
Demilitarized Zone (DMZ)
Client
InternetServer
Internet User
ClientClient
CorporateServer
RoutingSecurity
(prevention of attacks, viruses, banned content,...)
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Features - Integration of external Users
Example
Router
Internet
Firewall
Security Server
WLAN
Mobile phoneof mobile user
Mobile radio
LAN
ClientClient
Client
CorporateServer
Desktop computer ofhome user
Notebook of mobile user
Controls access rightsand allows or blocks
access to corporate services
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Features – Voice Integration in LAN (Voice over IP)
MultimediaGateway
TelephonyServer
Conferencingunit
VoIP device(Softphone)
Supports voice communication, optional video and data communication
Take care of delays and bandwidth!
Take care of delays and bandwidth!
VoIP device(Hardphone)
Public Switched Telephone Network
ISDN phone
LAN
Session controlControl of terminalsControl of gateways
AccountingBandwidth management
Conference(min. 3 partners)
Connection establishment
and release
Signal mix
Optional:Interconnects LAN and
PSTN Signalling
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Features – Video Surveillance over LANs (Video over IP)
Video Server
Monitor
Monitor forvideo
presentation
Videostorage
and processing
Video transmission
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Features - Mobilization
Client Mobilization:
User Mobilization:
AppApp App App
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Features - Virtualization
Virtualization in IT
Fields of application (examples):
System technology (CPU, RAM, harddisk, operating system, applications,...)
Servers, desktops, mobile devices
Network elements (switches, router)
Network connections
Data centers
Advantages: flexibilityCost reduction
Advantages: flexibilityCost reduction
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Features - Cloud Services
Public or private cloud services:
Computer and/or storage capacity “migrates” into the cloud
Advantages:
Use of software out of the cloud
Affordable storage and distribution of data
Co-operative work with data
Disadvantage:
Depending on solution no information about storage location
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Introduction to Local Area Networks
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Network Topologies - Star
Simple Star/tree:
Problem: reliabilityProblem: reliability
UniversalFlexible
FastEasy to implement
Future-proof
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Network Topologies - Star
SwitchSwitch SwitchSwitch
Point-to-Point
SwitchSwitch SwitchSwitch
Line
SwitchSwitch SwitchSwitch
SwitchSwitch SwitchSwitch SwitchSwitch
SwitchSwitch SwitchSwitch SwitchSwitch
SwitchSwitch SwitchSwitch SwitchSwitch
Star
SwitchSwitch SwitchSwitch SwitchSwitch
SwitchSwitch SwitchSwitch SwitchSwitch
SwitchSwitch SwitchSwitch SwitchSwitch
Tree
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Network Topologies - Star
SwitchSwitch SwitchSwitch SwitchSwitch
SwitchSwitch SwitchSwitch SwitchSwitch
SwitchSwitch SwitchSwitch SwitchSwitch
SwitchSwitch
SwitchSwitch
SwitchSwitch
SwitchSwitch
SwitchSwitch
SwitchSwitch
SwitchSwitch
SwitchSwitch
Mesh
Ring
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Network Topologies – Example: Star/Mesh Network
Problem: routing
Problem: routing
Ethernet
Redundancy increasesreliability
Introduction to Local Area Networks
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Network Topologies - Bus
Simple bus
Bus/tree:“Segment”
(= coaxial cable with termination resistors at both ends)
Easy to implementTotal failure in case of broken media
Hard to troubleshootSupports only 10 Mbps in LAN!
Problem: Not future-proof in
office LANs !
Problem: Not future-proof in
office LANs !„Ethernet“
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Network Topologies - Bus - Example
Universal Serial Bus (USB)
To interconnect computers („hosts“) with peripheral devices
Hierarchical, serial bus system
USB hub
USB hub
USB hub
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Network Topologies - Bus – Example: Field Bus System
Supports communication beteen simple field devices in industrial area and control systems
Replace single-wire harnessing
Valves, sensors, controller, flow rate measuring device, frequency inverter, barcode reader, fire detector,...
Programmablelogic control
Roboter control
Automationdevice ....
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Network Topologies - Ring
Single ring (without redundancy)
Multiple rings (with redundancy)
Complex network designMost often redundant rings
Token Ring4, 16 Mbps
100, 1.000 Mbps
Problem: No market
acceptance of ring topology in office
LANs!
Problem: No market
acceptance of ring topology in office
LANs!
Introduction to Local Area Networks
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Network Topologies – Ring - Example
Interconnected „Ethernet“ switches forming a loop:
Redundancy!
„Ethernet“ 1, 10 Gbps
40, 100 Gbps
Attention: requires intelligent switches!Attention: requires
intelligent switches!
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Network Topologies – Typical Characteristics
Star Bus Ring
Basic Topology
Complexity
Expandable
Redundancy
Characteristics
Scaleable
Future-proof
Transmissionprocedure
Simple
Yes
No
Yes
Yes
Serial protocol,CSMA
Simple
Yes
No
Yes
Office: NoFactory: Yes
CSMA, Token
Complex
Yes
Yes
Yes
Office: YesFactory: Yes
Serial protocol,CSMA, Token
Introduction to Local Area Networks
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Resources
Visit Ronald Schlager´s resources for more information:
Courseware: „Fundamentals of Local Area Networks - Part 1 / 2“
Courseware: „Fundamentals of Local Area Networks - Part 2 / 2“
Book: „Abbreviations in Communications Technologies“
Book: „The OSI Model – simply explained“
Web:
Ronald Schlager´s Blog
www.ronaldschlager.com
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