• Network Fundamentals
• Local Area Network (LAN)
• Open Systems Interconnection (OSI)
• LAN Architectures

• Definitions
• Classifications
• Network topology
• Network types
• Local Area Network

• Network
• Backbond network

• Topology
• Ownership
• Geography
• Transmission

• Star
• Hierarchical
• Mesh
• Bus
• Ring
• Hybrid

• Usage
– Centralized processing or communication
• Pros
– Expansion
– Implementation
– No limit to no. and length of arms
• Cons
– Single point of failure
– Overload of mater during peak traffic

• Usage
– Distributed processing
• Tree structure with a root
• pro
– No single point of failure

• Web structure
• Usage
– Public telephone system
• Pro
– Alternative communication route
• Con
– Line cost

• Usage
– Date entry or office environment
• Pros
– Independent between nodes
– High reliability
• Cons
– Limited number of attached device
– Hard to locate the problems

• Usage
– Manufacturing
• Pros
– Less attenuation
– Error control
– Network management
• Cons
– Failing of a node

• Usage
– Connecting different networks
• Pro
– Communication between networks
• Con
– Conversion device and costs
– Compatibility

• Private networks
• Public networks
• Valued added networks

• Full control
• Special needs
• Expense

• Controlled by carriers
• Regulated by government
• Inexpensive

• Functions
– Code translation
– Speed conversion
– Store message and delivery
• Examples
– Telex
– SWIFT
– SITA (airline)
– IVAN (insurance)

• Wide area network (WAN)
• Metropolitan area network (MAN): 30 miles
• Local area network (LAN): 5 miles

• Limited distance within a few miles
• High data rate - 2 to 1000Mbps
• Low error rate
• Good response time
• Private owned
• No regulation
• Share hardware, software, and data files

• Corporate asset for competitive edge
• Data accessibility (information distribution)
• Less expenses
• Better service - response time and reliability
• Higher productivity
• Control or secure

• Meet business objectives (strategic planning)
• Prevent technological obsolescence

• Hardware
– PC: servers and clients
– Network interface card (NIC): physical address
– Media or Cables
• Unshielded twisted pair (inexpensive)
• Coaxial cable (faster, expensive)
• Optical fiber (fastest, expensive)
• Air for wireless
– Hub (compatible)
• connect wires and cables, repeater, error detection
• Software: network operating system

• International Standards Organization
• Interconnection of dissimilar network
• Seven Layers
– Application
– Presentation
– Session
– Transport
– Network
– Data Link
– Physical

• Utilities support end-user application program
• Determine data to be send at originating end
• Process data at receiving end

• Change data format
• Compression/expansion
• Encryption/decryption

• Communication rules of machines or application programs
• Accounting functions

• Identify receiving address
• Flow control: rate of transmission
• Recovery: calculate and check checksum of entire message

• Route message
• Dissemble and assemble data (packets)
• Accounting functions

• By IEEE 802
• Establish link between two ends
• Detect and correct transmission error
• Add header and trailer
• Divide data unit for transmission (frames)
• Sublayers
– Media access control (MAC): token ring or
Ethernet
– Logical link control (LLC): assembling and disassembling frames, error control, flow control

• Electrical, mechanical, procedural specifications for data transmission
• Hardware specification by RS-232-C

• Protocol
• Encapsulation/ de-encapsulation

• IEEE 802.2: LLC protocol
• IEEE 802.3: CSMA/CD baseband bus
• IEEE 802.4: token passing bus
• IEEE 802.5 token passing ring
• Fiber Distributed Data Interface (FDDI)
Standard

• Network architecture includes
– Access methodology
– Logical topology
– Physical topology
• Network configuration includes
– Network architecture
– Media choice

• Contention: carrier sense multiple access with collision detection (CSMA/CD)
– Inexpensive NIC
– For: office application
– Not for: manufacturing due to inconsistent response time
• Token passing: 24 bits of token (free or busy)
– More efficient at higher network utilization rate
– More expensive NIC
– Supported by IBM

• Logical
– Sequential
– Broadcast
• Physical
– Bus: line broken
– Ring: PC or NIC broken
– Star (hub, concentrator, MAU (multistation access unit, repeater, switching hub): single point of failure

• Functionality
– Access method: CSMA/CD
– Logical topology: broadcast
– Physical topology: bus or star
• Ethernet II
– Header (preamble) for synchronizing
– Destination & source address (MAC layer address)
– Type field for network protocol
– Data field
– Frame check sequence (FCS): CRC-32
• IEEE 802.3 replace type field with length field

• 10BaseT
• 10Base2 (Thinet with RG-58 coax)
• 10Base5 (thick coaxial cable RG-11)
• 100BaseT Fast Ethernet with 100-Mbps
– 100BaseTX (2 pair of Category 5 UTP or 1 pair of Type 1 STP)
– 100BaseT4 (4 pair of Category 3, 4, or 5 UTP)
– 100BaseFX (fiber optic cable)
– Trade off between speed and maximum network diameter
• Gigabit Ethernet (1000Base-X)

• Functionality
– Access method: token passing
– Logical topology: sequence
– Physical topology: ring or star
• IEEE 802.5
– Starting delimiter alert NIC about token approaching
– Access control field (1 for busy, 0 for free)
– Frame control field indicate regular data or network management frame
– Destination & source address (MAC layer address)
– Routing information field for multiple token ring LANs
– Data field
– Frame check sequence (FCS): CRC-32
– Ending delimiter (ending or intermediate frame)
– Frame status field for successful delivery

• Fiber distributed data interface (FDDI) by
American National standard Institute (ANSI)
• Functionality
– Access method: Modified token passing
– Logical topology: sequential
– Physical topology: dual counter-rotating rings
• Build-in reliability and longer distance
• Single-attachment stations (SAS) or dualattachment stations (DAS)

• High speed backbone between LANs
• Primary ring and secondary ring - 100Mbps token ring
• Fault tolerance
• High-priority station having longer access time
• Maximum 500 stations
• Maximum length of 200 kilometers (rings)
• Maximum 2 kilometers between stations
• Constant data rate for video and voice

• Applications
– Campus backbone
– High-bandwidth workgroups (multimedia application)
– High-bandwidth subworkgroup connection
(servers)
• Hardware: FDDI concentrator or hub,
FDDI/Ethernet bridge
• Media: fiber optic cable or copper distributed data interface (CDDI) for limited distance (100m)

• Ethernet and token ring packets
• Demand priority access (DPA) or demand priority protocol: round robin polling scheme
• Priority is assigned by application program and ports
• Max 4 hubs between two nodes

• Hardware: 100VG-AnyLAN hubs arranged in a hierarchical form
• Media: 4 pair of Category 3, 4, or 5 UTP; 1 pair of Type 1 STP; or single mode and multimode fiber optic cable

• Iso-Ethernet in IEEE802.9a (Isochronous
Ethernet Integrated Services)
• Synchronize all circuits with a single common clocking reference
• Guaranteed delivery time for voice and video
• Use ISDN WAN link

• 16.144-Mpbs bandwidth
– P channel for Ethernet traffic
– C channel ( B channel and D channel)
• Service Modes
– 10BaseT
– Mutiservice: multimedia
– All-isochronous: real time video or voice distribution

• Hardware:
– hubs: Iso-Ethernet attachment units (AU)
– Workstation with Iso-Ethernet NIC: integrated service terminal equipment (ISTE)

• Transmitter and receiver
• 100 - 300 feet
• Infrared technology (line-of-sight)
• Spread spectrum technology (no ling-ofsight)
• Special application

• Protocol (CSMA/CD, token ring)
• Speed of transmission (line)
• Amount of traffic
• Error rate
• Software
• Hardware

• Long range thinking, planning and forecasting
• Selection team
• Checklist of criteria
• Cost & benefit analysis
• Technical alternatives
• Management and Maintenance

• Number of user
• Geographic spread
• Applications
• Performance
• Cost
• Security
• Wiring

• Installation
• Maintenance
• Vendor support and training
• Future expansion
• Workstations
• Compatibility to existing LANs
• Interface to other networks

• Workstations
• Servers
• Printers
• Cabling
• Bridges, routers, brouters, gateways
• Training
• People (consultant, administrator etc.)
• Maintenance
• Space & Environment

• Choices
–
Suppliers or dealers
–
In house
•
Tasks (project management)
–
Install hardware and software
–
Test access and capability
–
Trouble shoot
– Document
– Train user
– Help center

• Organization: LAN administrator
• Management: policies and procedures
• Documentation
• Hardware and software control
• Change control
• Back up (hardware and software)
• Security (logical and physical)
• Application (compatibility, integrity, & efficiency)
• Performance monitoring

• Password
• Sign off
• Encryption
• Backup
• Downloading
• Viruses protection
• Dial-up access
• Legal software
• Internal and external auditing
• Written policy and procedure

• Review chapter 5
• Read chapter 6