Network Fundamentals

1
Chapter 11

• Network Fundamentals

2
Agenda

• Definition
• Classification
• Information Routing
• Connection
• Telecommunication software
• Architecture

3
Definition

• Network
• Backbone network

4
Classification

• Topology
• Ownership
• Geography
• Transmission

5
Network Topology

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

6
Star Network

• Circuits
• Point-to-point, multipoint, or combination
• Pros
• Expand
• Implement
• No limit to no. and length of arms
• Cons
• Single point of failure
• Overload of mater during peak traffic

7
Hierarchical Network

• Tree structure with a root
• pro
• No single point of failure
• Divisional communications and processing

8
Mesh Network

• Web structure
• Usage
• Public telephone system
• Pro
• Alternative communication route
• Virtually fail-safe
• Con
• Line cost

9
Bus Network

• Usage
• High speed, short distance between nodes
• Local area network
• Pros
• Independent between nodes
• High reliability
• Cons
• Limited number of attached device
• Hard to locate the problems

10
Ring Network

• Usage
• Nodes are relatively close together
• Pros
• Less attenuation
• Error control
• Network management
• Cons
• Failing of a node
• Two opposite direction channels

11
Hybrid Networks

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

12
Network Ownership

• Private networks
• Public networks
• Valued added networks

13
Private networks

• Full control
• Special needs
• Expense

14
Public networks

• Controlled by carriers
• Regulated by government
• Inexpensive

15
Valued Added Networks

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

16
Networks by Geography

• Wide area network (WAN)
• Metropolitan area network (MAN)
• Local area network (LAN)

17
Wide Area Networks

• Public Switched Telephone Network (PSTN)
• Provided by carriers
• Inexpensive
• High quality service for infrequent users

18
Metropolitan Area Networks

• IEEE 802.6
• Distance up to 30 miles
• High bandwidth for data, voice, and video
• T1, T3, or fiber optic cable
• Private own or dark fiber supplied by MAN
  provider

19
Network Transmission Types

• Circuit Switching
• Packet data networks (PDNs)
• Frame relay
• Asynchronous transfer mode ATM (Cell relay)

20
Circuit Switching

• Temporarily Dedicated communications line between
  two stations for transmission
• Efficient for constant voice and video
  transmission
• Inefficient for non-constant data transmission

21
Packet Data networks (PDNs) - I

• Packet
• Less than 1,000 bytes
• PAD (packet assembly/disassembly)
• Address and control fields for error checking
• Connection types
• Switched virtual circuit dial-in (switched)
• Permanent virtual (leased) circuit heavy
  frequent traffic
• Datagram short message, no error checking

22
Packet Data networks (PDNs) - II

• Standard
• ITU-Ts X.25
• Between terminal and PDN on public network
• ITU-Ts X.75
• Interface between two PDNs
• Examples
• USA APARANET, Telenet, Tymnet, General Electric
  Information Services (GEIS)

23
Packet Data networks (PDNs) - III

• Characteristics
• Reliable service
• Nationwide service
• Lower error rates
• Variety of transmission speeds
• Cost-effectiveness

24
Frame Relay

• Acknowledge only by final node
• Benefits
• Variable-length frames (1- 64,000 bytes)
• Reduce overhead
• More efficient transmission
• Problems
• Circuit congestion
• Committed information rate (CIR) port speed for
  service guarantee discarding frames

25
ATM (Cell-Relay)

• Asynchronous transfer mode (ATM)
• Cells fixed length packets of 53 bytes
• 45Mbps (T3) or higher speeds
• Pros
• High throughput, low delay, transparency,
  flexibility, and high capacity
• Con
• Expensive

26
ATM Services

• Realtime service
• Constant bit rate (CBR) for telephone and
  videoconference
• Realtime variable bit rate (rt-VBR) for
  compressed video
• Non-realtime service
• Non-realtime variable bit rate (nrt-VBR) for
  airline reservation or financial transaction
• Available bit rate (ABR) for LAN-to-LAN
• Unspecified bit rate (UBR) for TCP-based traffic

27
Routing Message

• Connection-oriented routing connection less
  routing
• Broadcast routing
• Centralized routing
• Distributed routing
• Static and dynamic routing

28
Broadcasting Routing

• CSMA/CD
• Pros and cons
• Simplest
• For small network
• Not for moderate to heavy traffic

29
Centralized Routing

• Star or hierarchical networks
• IBMs SNA networks
• Using static routing table in one central
  computer
• Pros and cons
• Simple
• Potential performance bottleneck
• Single point of failure

30
Distributed Routing

• Routing tables on several nodes
• Pros and cons
• No single point of failure
• Routing table update problem
• Complicated to implement

31
Static and Dynamic Routing

• Static routing
• Predetermined route
• Simple but inflexible
• Dynamic routing
• Use routing algorithms to evaluate traffic
  volumes, error rates, and other conditions for
  the best path
• Flexible but high overhead and complicated to
  implement

32
Interconnecting Networks

• Transmission control protocol/ internet protocol
  (TCP/IP)
• Internet
• Intranet extranet

33
Transmission Control Protocol

• OSI transport layer
• Connection oriented
• Functions
• Assemble and reassemble message packets
• Reliable error free message delivery
• Urgency or priority
• Security (encryption)

34
Internet Protocol

• OSI network layer
• Routing addressing messages to other networks
• Connectionless operation
• IPv6
• 128 bits for addressing
• Quick and efficient

35
TCP/IP Application protocols

• File Transfer Protocol (FTP)
• Tenet
• Simple Mail Transfer Protocol (SMTP)
• Multipurpose Internet Mail Extensions (MIME)
• Remote Procedure Call (RPC)
• Simple Network Management Protocol (SNMP)

36
Internet

• Usages
• Electronic mail, remote log in to various
  computers, discussion groups, information search
  and retrieval
• Electronic mail (e-mail)
• Edu, com, org, gov, mil, net
• Web servers web browsers
• Hypertext Markup Language (HTML)
• Uniform Resource Locator (URL)
• Home page
• Internet service provider (ISP)

37
Intranets Extranets

• Intranets
• Extranets
• Benefits fast information transmission
• Problems security privacy

38
Connect Network to Computer

• Methods
• Direct connection between circuit and computer
• Small network
• Low cost
• Cycle stealing
• Network interface card
• Use a front-end processor telecommunication
  control unit or transmission control unit
• Large host computer
• Better utilize computer resources

39
Front-end Processors (FEPs)

• Types
• Hardware (interface or port) speed
• Software ( network control program NCP) flexible

40
FEPs - Functions

• Circuit control
• Assembly messages
• Message queuing or storing
• Error control
• Administration functions

41
Functions of Telecommunication Softwarein Host
Computer

• Security
• Buffer management
• Routing a message to a program
• Queuing messages
• Scheduling application program
• Providing continuity between part of a
  transaction
• Message formatting
• Checkpoint/restart
• Preventing messages from lost or duplicated

42
Software for Network Management

• Control and monitor the network status
• Start/stop network, terminal, and line
• Performance
• Log network operation
• Display network data

43
Manufacturers Architectures

• IBMs System Network Architecture (SNA)
• Digital Equipment Corporations Digital Network
  Architecture (DNA)

44
IBMs SNA Concepts

• Physical units
• Logical units
• Sessions
• Network addressing units (NAUs)
• Data link protocols
• SNA software
• Network Control program (NCP)
• Virtual Telecommunications Access Method

45
SNA Physical Units

• Terminals (1)
• Cluster controllers (2)
• Front-end processors (4)
• Host computers (5)

46
SNA Logical Units

• People
• Application programs

47
SNA Sessions

• Types
• Terminal-to-terminal
• Terminal-to-program
• Program-to-program
• Modes
• Interactive
• Batch
• Multiple simultaneous

48
SNA Network Addressable Units

• Physical units
• Logical units
• Address 24 bits

49
SNA Data Link Protocols

• Synchronous Data Link control (SDLC)
• Binary Synchronous Communications (BISYNC or BSC)
• X.25

50
System Network Architecture

• Physical control
• Physical and electrical connections
• Transmission codes
• Voltages
• Data link control
• Format
• Reliability
• Path control
• Routing information
• Transmission control
• Security compression
• Data flow control
• Flow control
• Presentation services
• Format
• Transaction services
• Coordinating application software

51
Digitals DNA -I

• Protocols
• Digital Data Communication Message Protocol
  (DDCMP)
• X.25
• Ethernet
• DECNET Layers
• Application
• Network service
• Transport
• Data link control
• Physical link control

52
Points to Remember

• Definition
• Classification
• Information Routing
• Connection
• Telecommunication software
• Architecture

53
Discussion

• Does CSUS need a backbone network?
• What type of backbone do you think that CSUS
  needs (give your justifications)?
• What type of network does CSUS needs in terms of
  topology, ownership, geography and transmission
  technology?
• What type of network does a grocery chain store
  needs in terms of topology, ownership, geography
  and transmission technology?