Chapter 4 Internet Architecture

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Chapter 4Internet Architecture
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OVERVIEW
Internet Architecture

• What is a Network?
• IP Addresses
• Networks
• Information Transfer
• Cable Types
• Key Components of a Network
• Factors in Designing a Network
• Network Management System

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WHAT IS A NETWORK?
Internet Architecture What is a Network?

• A connection between at least two computers for
  the purpose of sharing resources
• Types
• Local Area Networks (LANs)
• Wide Area Networks (WANs)
• Metropolitan Area Networks (MANs)

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PEER-TO-PEER NETWORK
Internet Architecture What is a Network?

• Computers linked together as equals
• No centralized control
• Share resources on the same network in any way
  at any time
• Promotes institutionalized chaos
• lt 10 computers

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PEER-TO-PEER NETWORK (CONT.)
Internet Architecture What is a Network?

• Benefits
• Easy to install/configure
• Inexpensive
• Users able to control their own resources
• Independent from a dedicated server
• No need for a network administrator

• Drawbacks
• Security problems
• Performance suffers when a computer is accessed
• Difficult to have backup
• Decentralized logon passwords
• No centralized data management

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CLIENT/SERVER NETWORK
Internet Architecture What is a Network?

• Server designed to address a clients request
• Client any computer connected to the server
  within a network
• Allow authorized user to access any
  programs/application residing on the server

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CLIENT/SERVER NETWORK (Contd)
Internet Architecture What is a Network?

• Benefits
• Centralized security control
• Simpler network administration than peer-to-peer
  network
• Centralized password
• More scalable
• Ideal for computers that are apart

• Drawbacks
• Network failure clients are helpless
• Specialized staff are needed
• Higher costs

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IP ADDRESSES
Internet Architecture IP Addresses

• A host number to identify itself to other hosts
• Consists of strings of 32 bits
• E.g. 10111111010101010100000000001100
  191.170.64.12
• Host Name
• Human-friendly Internet addresses
• E.g. ema3z.mcintire.virginia.edu

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NETWORKS
Internet Architecture Networks

• Network vs. Local
• Networks are classified by three sizes

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NETWORKS (Contd)
Internet Architecture Networks

• Zones
• Three-letter kind (com, gov, edu)
• Two-letter kind (ca, uk, jp)
• New general-purpose zones (firm, store)

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INFORMATION TRANSFER
Internet Architecture Information Transfer

• Packet
• Grouping of data for transmission on a network
• Large messages are split into a series of packets
  for transmission
• Protocol
• A rule governing how communication should be
  conducted
• Internet Protocol
• Set of rules used to pass packets

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INFORMATION TRANSFER (Contd)
Internet Architecture Information Transfer

• Open Systems Interconnection (OSI)
• A layered approach to networking
• Each layer handles a different portion of the
  communication process

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OSI REFERENCE MODEL
Internet Architecture Information Transfer
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OSI REFERENCE MODEL (Contd)
Internet Architecture Information Transfer

• Application Layer
• Defines requests response formats
• Standard HTTP
• Governs requests response between browser web
  server application program
• Other standards SMTP, POP
• HTML-compatible
• File Transfer Protocol (FTP), Simple Network
  Management Protocol (SNMP), Domain Name Service
  (DNS)

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OSI REFERENCE MODEL (Contd)
Internet Architecture Information Transfer

• Presentation Layer
• Converts data into a format the receiving
  application can understand
• Session Layer
• Exchanges data for the duration of session
• Keeps track of the status of exchange
• Ensures only designated parties are allowed to
  participate in the session
• Enforces security protocols for controlling access

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OSI REFERENCE MODEL (Contd)
Internet Architecture Information Transfer

• Transport Layer
• Manages the transmission of data across a network
• Transmission Control Protocol (TCP)
• Specifies how two host computers will work
  together
• Flow control
• Sequence assurance
• Reliability integrity

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OSI REFERENCE MODEL (Contd)
Internet Architecture Information Transfer

• Internet Layer
• Routes messages across multiple nodes for
  delivery
• Handles network congestion to minimize
  performance problems
• Internet Protocol (IP)
• Standard for routing packets

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OSI REFERENCE MODEL (Contd)
Internet Architecture Information Transfer

• Data Link Layer
• Packages data into frames for delivery
• Point-to-point (PPP)
• Framing mark boundary between packets
• Error detection
• Ethernet
• Physical Layer
• Converts bits into signals for outgoing messages
  signals into bits for incoming messages

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CABLE TYPES
Internet Architecture Cable Types

• Twisted-Pair Cable
• Unshielded Twisted Pair (UTP)
• Shielded Twisted Pair (STP)
• Optical Fiber
• Coaxial Cable
• Wireless Technology

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TWISTED-PAIR CABLE
Internet Architecture Cable Types

• Consists of two pairs of insulated copper wires
  twisted around each other
• Advantages
• Protect against cross talk interference
• Easy to add computers to network
• Well understood technology
• Less expensive
• Disadvantages
• Susceptibility to noise
• Least secure
• Distance limitations
• Requires more expensive hubs

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UNSHIELDED TWISTED PAIR (UTP)
Internet Architecture Cable Types

• Pair of wires do not have the shielding against
  electrical interference
• Advantages
• Less expensive
• Easy to install
• Disadvantages
• Vulnerable to electromagnetic interference
  crosswalk
• Subject to attenuation

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SHIELDED TWISTED PAIR (STP)
Internet Architecture Cable Types

• An electrically grounded woven copper mesh
  wrapped around each twisted pair
• Advantage
• Reduces electromagnetic interference (EMI)
• Disadvantage
• Makes the wiring thick and is difficult to
  maintain

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OPTICAL FIBER
Internet Architecture Cable Types

• Uses light rather than voltage to indicate ones
  and zeros
• Advantages
• High speed transmission
• High security
• Smallest in size
• Supports voice video data
• Disadvantages
• Expensive
• Difficult to install
• Require two cables to transmit receive data
• Require special connections

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COAXIAL CABLE
Internet Architecture Cable Types

• Copper center shielded by a plastic insulating
  material
• Advantages
• Transmits up to 10Mbps over 500m
• Easy to install
• Low maintenance
• Good resistance to noise over long distances
• Disadvantages
• Inflexible
• Low security
• Limited distance

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WIRELESS TECHNOLOGY
Internet Architecture Cable Types

• Microwave
• Connect LANs in separate buildings
• Radio waves
• No distance limitations
• Susceptible to atmospheric and electronic
  interference
• Subject to government regulations
• Infrared transmissions
• Interference from bright light

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KEY COMPONENTS OF A NETWORK
Internet Architecture Key Components of a Network

• Network Interface Card (NIC)
• Hubs Switches
• Routers
• Gateways

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NETWORK INTERFACE CARD
Internet Architecture Key Components of a Network

• Installed in a slot with a cable plugged into the
  back
• Plugged into a wall jack connection or into the
  hub/switch directly
• Modem
• Converts digital signals into analog form for
  transmission and incoming analog signals into
  digital signal across the telephone line

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HUBS SWITCHES
Internet Architecture Key Components of a Network

• Hub
• Operates at Physical Layer
• Acts as a connecting point
• Passive, active, and intelligent hubs
• Switch
• Offers direct connection to a particular PC
• Available for almost every OSI level

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ROUTERS
Internet Architecture Key Components of a Network

• Operate at Internet Layer
• Evaluate network traffic and stop local traffic
  from causing congestion
• Filter out packets that need not be received
• Expensive difficult to operate

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GATEWAYS
Internet Architecture Key Components of a Network

• Special-purpose computer allowing communications
  between dissimilar systems on the network
• Operate at Application Layer primarily
• Difficult to install configure
• Expensive

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FACTORS IN DESIGNING A NETWORK
Internet Architecture Factors in Designing a
Network

• Location
• Capacity
• Distance limitations
• Cost
• Potential growth
• Security

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FACTORS IN SELECTING NETWORK ARCHITECTURE
Internet Architecture Factors in Designing a
Network

• Hardware requirements
• Software requirements
• Disaster recovery fault-tolerance requirements
• Corporate culture and organizational factors

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NETWORK MANAGEMENT SYSTEM
Internet Architecture Network Management System

• Manager
• Managed Nodes
• Objects
• Management Information Base (MIB)
• Requests responses

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Chapter 4Internet Architecture