Cs412 introduction to computer networking telecommunication
This presentation is the property of its rightful owner.
Sponsored Links
1 / 125

CS412 Introduction to Computer Networking & Telecommunication PowerPoint PPT Presentation


  • 104 Views
  • Uploaded on
  • Presentation posted in: General

CS412 Introduction to Computer Networking & Telecommunication. Introduction. Topics. Introduction Metric Units Network Hardware Network Software Reference Models Example Networks Standards and Standards Organizations. Introduction. First two decades of computing

Download Presentation

CS412 Introduction to Computer Networking & Telecommunication

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Cs412 introduction to computer networking telecommunication

CS412 Introduction to Computer Networking & Telecommunication

Introduction

Chi-Cheng Lin, Winona State University


Topics

Topics

  • Introduction

  • Metric Units

  • Network Hardware

  • Network Software

  • Reference Models

  • Example Networks

  • Standards and Standards Organizations


Introduction

Introduction

  • First two decades of computing

    • Highly centralized computer systems

  • Now

    • A large number of SEPARATE but INTERCONNECTED computers

      => Computer networks


What is computer network

What is Computer Network?

  • An INTERCONNECTED collection of AUTONOMOUS computers

    • Interconnected: Able to EXCHANGEINFORMATION via transmission media

      • Media: copper wire, fiber optics, microwaves, communication satellites

    • Autonomous: no master/slave relation

      • NOT autonomous:

        • One computer can control another one

        • e.g., a large computer with remote printers and terminals


What is telecommunication

What is Telecommunication?

  • What is data communication?

    • Exchange of data between two devices via some form of transmission media

    • Data are represented by bits – 0s and 1s

  • What is telecommunication?

    • Exchange of information over distance using electronic equipment


What is telecommunication1

What is Telecommunication?

  • Components of data communication

    • Sender, receiver, medium, message, and

    • Protocol: set of rules governing data communication

  • Key elements of a protocol

    • Syntax

      • Structure/format

    • Semantics

      • Meaning

    • Timing

      • When and how fast


Cs412 introduction to computer networking telecommunication

Figure 1.1Five components of data communication


Why studying cs412

Why Studying CS412?

  • The instructor looks nice … (Don’t bet on it!)

  • It is part of our daily life now

  • The job market is good … (?)

  • You want to understand concepts and technologies of networking and telecom

    • Theory and practice

  • It is one of the most drastically changing field in CS and you like challenges

  • It makes you knowledgeable in this field

  • It is FUN!!


Distributed system vs computer network

Distributed System vs. Computer Network

  • Distributed system

    • TRANSPARENCY

      • A collection of independent computers appear as a single coherent system

    • Single model/paradigm to users

    • Middleware on top of OS

    • Example?

  • Computer network

    • No such coherence, model, middleware

    • Machines visible to users

      • Users log onto remote machines


Distributed system vs computer network1

Distributed System vs. Computer Network

  • A distributed system is a SOFTWARE system built on top of a network

  • Distinction between network and distributed system

    • Software (especially OS) rather than hardware

  • However, considerable overlap between the two subjects


Uses of computer networks

Uses of Computer Networks

  • Business applications

    • Resource sharing

    • Communication medium

    • E-commerce

  • Client-server model

    • Client requests, server performs & then replies

    • E.g., one or more file servers, many clients


Business applications of networks

Business Applications of Networks

  • A network with two clients and one server.


Client server model

Client-Server Model

1

2

3


Uses of computer networks1

Uses of Computer Networks

  • Home applications

    • Access to remote information

      • On-line publishing, digital library, WWW

    • Person-to-person communication

      • Email, instant messaging, peer-to-peer communication, videoconferencing, Internet phone, E-learning

    • Interactive entertainment

      • Video on demand (VOD), games

    • E-commerce

      • Home shopping, electronic banking and investment, on-line auction


Home network applications 2

Home Network Applications (2)

  • In peer-to-peer system there are no fixed clients and servers.


Mobile users

Mobile Users

  • Notebook, PDA, cellular phone

  • M-commerce

  • Wireless networking and mobile computing


Metric units

Metric Units

  • The principal metric prefixes.


Network hardware

Network Hardware

  • By transmission technology

    • Broadcast links

      • smaller, geographically localized networks

    • Point-to-point links

      • larger networks

  • By scale

    • PAN

    • LAN

    • MAN

    • WAN


Classification by scale

Classification by Scale


Broadcast network

Broadcast Network

  • A single communication channel shared by all machines on the network

  • Packets (short messages) sent by any machine are “received” by all the others

    • Address field of packet: whom it is intended

  • Message transmission

    • Unicast: one sends, one receives

    • Broadcasting: one sends, all receive

    • Multicasting: one sends, a group receives


Point to point networks

Point-to-Point Networks

  • Many connections between pairs of machines

  • Intermediate machines (called routers) might have to be visited by a packet from source to destination – more than one path is possible

  • Routing algorithms are important

    • Routing: process of finding a path from a source to the destination(s) in the network


Local area network lan

Local Area Network (LAN)

  • Private-owned Networks

  • Within a single building/campus

  • Size: up to a few kilometers

  • Characteristics

    • Size

      • Restricted by size

         worst-case transmission time bounded and known in advance

         network management simplified


Cs412 introduction to computer networking telecommunication

LAN

  • Characteristics

    • Transmission technology

      • Machines attached to a single cable

      • Speed/capacity (High): 10 - 100 Mbps, Gbps

        • Mbps/Gbps: Megabit/Gigabit per second

        • 1 megabit=1,000,000 (not 220=1,048,576) bits

      • Delay (low): microseconds, nanoseconds

      • Errors: very few


Cs412 introduction to computer networking telecommunication

LAN

  • Characteristics

    • Topology – the way in which a network is laid out

      • Examples: Bus, Ring

Bus

Ring


Cs412 introduction to computer networking telecommunication

Figure 1.7Categories of topology


Cs412 introduction to computer networking telecommunication

Figure 1.8Fully connected mesh topology (for five devices)


Cs412 introduction to computer networking telecommunication

Figure 1.9Star topology


Cs412 introduction to computer networking telecommunication

Figure 1.10Bus topology


Cs412 introduction to computer networking telecommunication

Figure 1.11Ring topology


Lan topology

LAN - Topology

  • Bus (linear cable)

    • Only one machine can transmit at a time

    • Arbitration mechanism needed to resolve conflicts when two or more computers want to transmit simultaneously

      • Centralized or Distributed

    • Example: IEEE 802.3 (Ethernet):

      • Bus-based broadcast network with decentralized control operating at 10 Mbps to 10Gbps.

      • If two or more packets collide, each computer just waits a random time and tries again later.


Lan topology1

LAN - Topology

  • Ring

    • Bits propagate around the ring

    • Arbitration mechanism is needed, too

    • Example: IEEE 802.5 (IBM Token Ring)

      • Ring-based LAN operating at 4 and 16 Mbps

      • Arbitration is based on “token”

        • Only token holder can transmit


Lan channel allocation

LAN - Channel Allocation

  • Needed as all computers share one communication pathway

  • Static channel allocation

    • Divide up time into discrete intervals

    • Run a round robin algorithm

    • Allow each machine to broadcast only when its time slot comes up

    • Problem: Wasting channel capacity


Lan channel allocation1

LAN - Channel Allocation

  • Dynamic channel allocation

    • Centralized

      • A central entity determines who goes next

    • Decentralize

      • No central entity

      • Each machine decides for itself to transmit or not

      • Algorithms needed to resolve potential chaos


Metropolitan area network man

Metropolitan Area Network (MAN)

  • Covers city

  • Examples

    • Cable TV network

    • IEEE 802.16 high-speed wireless Internet access


Cs412 introduction to computer networking telecommunication

Figure 1.14 MAN


Metropolitan area networks

Metropolitan Area Networks

  • A metropolitan area network based on cable TV.


Wide area network wan

Wide Area Network (WAN)

  • Country or continent

  • Components

    • Host (end system)

      • Machine running user (application) programs

    • Communication subnet (subnet)

      • Connecting hosts

      • Carrying messages from host to host


Cs412 introduction to computer networking telecommunication

Figure 1.15WAN


Wan subnet components

WAN - Subnet Components

  • Transmission lines

    • Move bits between machines

  • Switching elements

    • Specialized computers that connect two or more transmission lines

    • Determine out going line for incoming data

    • ROUTER


Wan hosts and subnet

WAN - Hosts and Subnet

H1

R1

R2

R3

R4

R5

R6

H2

: Host

: Router


Wan architecture

WAN - Architecture

  • Contains numerous cables or telephone lines

  • Each cable connects a pair of routers

  • Two routers must communicate indirectly if they are not connected by a cable

  • There might be more than one route between two hosts and it might change from time to time

    • E.g., Route from H1 to H2


Wan architecture1

WAN - Architecture

  • An intermediate router in a WAN

    • Receives a packet in its entirety

    • Queues the packet until required output line is free

    • Forwards the packet

  • Subnet using the principle above is called

    • Store-and-forward or packet-switched subnet


Wide area networks

Wide Area Networks

  • A stream of packets from sender to receiver.


Topology lans vs wans

Topology – LANs vs WANs

  • Local networks

    • Bus, Ring, Star

    • Tree

  • WANs typically irregular


Wan broadcast systems

WAN - Broadcast Systems

  • Satellite system

    • Each router has an antenna

    • Sometimes routers are connected to a substantial point-to-point subnet, with some of them having a satellite antenna

    • Inherently broadcast


Wireless network

Wireless Network

  • System interconnection

    • Example: Bluetooth

  • Wireless LANs

    • Easy to install

    • IEEE Standard 802.11

  • Wireless WANs

    • IEEE Standard 802.16


Wireless networks

Wireless Networks

Bluetooth configuration Wireless LAN


Wireless network1

Wireless Network

  • Combinations of wired and wireless networking (e.g., flying LAN)


Home network categories

Home Network Categories

  • Computers

    • Desktop PC, PDA, shared peripherals

  • Entertainment

    • TV, DVD, VCR, camera, stereo, MP3

  • Telecomm

    • Telephone, cell phone, intercom, fax

  • Appliances

    • Microwave, fridge, clock, furnace, aircon

  • Telemetry

    • Utility meter, burglar alarm, babycam


Internetwork

Internetwork

  • What is internetwork?

    • A collection of interconnected networks

  • "Internet" and "internet"

    • internet: internetwork

    • Internet: the worldwide internetwork using TCP/IP protocol suite

  • Problem: Communication between networks with different SW/HW

    • Solution: Gateways

      • Machines connect different, incompatible networks

      • Connection and translation


Cs412 introduction to computer networking telecommunication

Figure 1.16Internet today


Network software

Network Software

  • Old computer networks:

    • HW main concern

    • SW afterthought

    • Not working now!

  • Network SW is now highly structured

    • Protocol Hierarchies

    • Implemented in hardware or firmware


Protocol hierarchies

Protocol Hierarchies

  • What is protocol?

    • Agreement between communication parties on HOW communication is processed

  • Layered architecture

    • Reduce design complexity- Lower layer offers service to higher layer

    • Hiding implementation details

    • Layer n on one machine talks to layer n on another

    • Rules and conventions used in layer n’s talk: Layer n protocol


Protocol hierarchies1

Protocol Hierarchies

  • Peers

    • Entities comprising corresponding layers on different machines

    • Virtual communication using protocol

    • Peer process abstraction make network design becomes that of individual layers

  • Physical communication

    • Sender: Data and control passed to layer below

    • Data transmitted via physical media

    • Receiver: Data and control passed to layer above


Layers protocols and interfaces

Layers, Protocols, and Interfaces

Virtual Communication

Physical Communication


Protocol hierarchies2

Protocol Hierarchies

  • Interface between two adjacent layers

    • Defines primitive operations and services a lower layer offers to the upper one

    • Minimizes amount of information passed between two layers

    • Simplifies replacement of implementation

      • E.g., telephone lines  satellite channels


Protocol hierarchies3

Protocol Hierarchies

  • Network architecture

    • Set of layers and protocols

    • Implementation and interface specification not included

  • Protocol stack

    • A list of protocols used by a certain system, one protocol per layer


Multilayer communication example

Multilayer Communication - Example

  • Philosopher-translator-secretary architecture

    • It is ok if

      • Dutch is

        replaced by

        Finnish

      • fax is

        replaced by

        email


Information flow example

Information Flow - Example

  • Virtual communication for layer 5

    • Header: control information

Layer 1

protocol

00011100011100001110 …

00011100011100001110 …


Key design issues for the layers

Key Design Issues for the Layers

  • Sender/receiver identification mechanism

  • Transmission direction modes

    • Simplex

      • Data only travel in one direction

    • Half-duplex

      • Data can travel in either direction, but not simultaneously

    • Full-duplex

      • Data can travel in both directions simultaneously

  • Number of logical channels and properties


Key design issues for the layers1

Key Design Issues for the Layers

  • Error control

    • Error-detecting

    • Error-correcting

  • Sequencing

  • Flow control 

    • Needed for fast sender, slow receiver

    • Approaches

      • Feedback mechanism

      • Transmission rate agreement


Key design issues for the layers2

Key Design Issues for the Layers

  • Message disassembling, transmitting, reassembling

  • Multiplexing

    • The process of combining signals from multiple sources fortransmission across a single data link

    • Multiple connections can share the link

  • Routing

    • Selecting the best path for sending a packet from one point toanother


Connection oriented and connectionless services

Connection-Oriented and Connectionless Services

  • Two basic types of services

    • Connection-oriented

    • Connectionless

  • Consider reliability …

    • ReliableConnection-oriented

      UnreliableConnectionless

  • Note that: Connection  Reliability


Connection oriented service

Connection-Oriented Service

  • A connection is established first, then used, and then released when done.

  • Works like a pipe:

    • Sender pushes data in at one end

    • Receiver takes them out, often in the same order, at the other end

  • Analogy

    • Telephone system


Connectionless service

Connectionless Service

  • No need to set up a connection first

  • Each message carrying full destination addressis routed independently of others

    • No guarantees on the order

  • Analogy

    • Postal system


Six service types

Six Service Types


Service primitives

Service Primitives

  • Service is formally specified by a set of primitives (e.g., OS’s system calls) available to users or entities

  • Five service primitives for implementing a simple connection-oriented service.


Service primitives1

Service Primitives

  • Packets sent in a simple client-server interaction on a connection-oriented network.


Relationship of services to protocols

Relationship of Services to Protocols

  • Service

    • Set of primitives a layer provides to the layer above it

    • Define WHAT operations

      not HOW implemented

  • Protocol

    • Set of rules governing format and meaning of message exchanged by peer entities within a layer

    • Used by entities to implement service definition


Services to protocols relationship

Services to Protocols Relationship

  • The relationship between a service and a protocol.


Relationship of services to protocols1

Relationship of Services to Protocols

  • Analogy: Object-oriented languages

    • Service :: Object

      • Users do not know the implementation of a service

    • Protocol :: Implementation

      • The protocol of the service is invisible to users

      • Do you have to understand http (hypertext transport protocol) before you can surf the Internet?


Reference models

Reference Models

  • Two reference models will be discussed

    • OSI reference model

    • TCP/IP model


Osi reference model

OSI Reference Model

  • ISO/OSI (Open Systems Interconnection) Reference Model

  • NOT a network architecture itself

    • Exact services and protocols are not specified

    • Just "what should be done" in each layer

    • However, standards are produced for all layers


Osi reference model1

OSI Reference Model

  • Seven layers

    • Layer 7: application layer

    • Layer 6: presentation layer

    • Layer 5: session layer

    • Layer 4: transport layer

    • Layer 3: network layer

    • Layer 2: data link layer

    • Layer 1: physical layer (lowest)

  • Diagram of OSI reference model

    • Note: this is one of the most important figures in the whole book!!


Cs412 introduction to computer networking telecommunication

Physical medium


Cs412 introduction to computer networking telecommunication

Physical medium

End-to-End

Point-to-Point

Point-to-Point

Point-to-Point

Host B

Host A

Subnet


Physical layer

Physical Layer

  • Transmitting raw bits (0s and 1s)

  • Design issues

    • Representation of bits

      • How is 0/1 represented?

    • Data rate: number of bits sent per second

      • How long does a bit last?

    • Transmission mode

    • Mechanical, electrical, procedural interfaces

    • Underlying physical transmission medium


Data link layer

Data Link Layer

  • Takes a raw transmission facility and transforms it into a line (link) that appears free of undetected transmission errors to networklayer

  • Basic function

    • Breaks up input data to data frames

    • Transmits data frames

    • Processes acknowledgement frames sent back from receiver


Data link layer1

Data Link Layer

  • Responsibilities (cont’d)

    • Physical addressing

    • Framing

      • creating and recognizing frame boundaries

    • Error control (adjacent nodes)

      • Errors: damaged, lost, duplicate

    • Flow control (adjacent nodes)

      • Traffic regulation between fast sender and slow receiver

    • Medium access control

      • Shared channel access control in broadcast networks


Network layer

Network Layer

  • Subnet operation control

  • Responsibilities

    • Logical addressing

    • Routing

      • Static tables

      • Determined at the start of conversation

      • Dynamic

    • Congestion control

    • Quality of service

    • Accounting

    • Heterogeneous network interconnection


Transport layer

Transport Layer

  • End-to-end layer

    • Talk to destination machine directly (virtually)

    • Layers 4 through 7 are end-to-end

    • Layers 1 through 3 are node-to-node

  • Basic function

    • Split data from session layer into smaller units

    • Pass units to network layer

    • Ensure units arrive correctly at the other end


Transport layer1

Transport Layer

  • Determine services provided to session layer (and ultimately to users)

    • Error-free point-to-point channel that delivers messages in theorder in which they were sent

    • Transport of isolated messages w/o guarantee about order

    • Broadcasting

  • Normally, a distinct network connection is created for each transportconnection required by session layer


Transport layer2

Transport Layer

  • Responsibilities include

    • Service-point addressing

      • Which message belong to which connection (application):

        • Information in header  

        • Needed as multiprogramming in a host

    • (End-to-end) Flow control Compare to the

    • (End-to-end) Error control Data Link layer


Session layer

Session layer

  • Session establishment between users on different machines

  • Responsibilities

    • Dialogue control

      • Deciding who sends, and when

    • Token management

      • Control of same operation not to be performed at the same time

    • Synchronization

      • Inserting checkpoints (checkpointing)


Cs412 introduction to computer networking telecommunication

Figure 3-11 from Forouzan’s 2/e

Session Layer

The McGraw-Hill Companies, Inc., 1998

WCB/McGraw-Hill


Presentation layer

Presentation Layer

  • Syntax/semantics of information

  • Responsibilities

    • Encoding

      • Convert from data representation used in one host to the standard abstract data structure and back

    • Encryption

    • Compression


Application layer

Application Layer

  • Provides interface and support for services to users (human, software, robots)

  • Application services

    • Network virtual terminal (telnet)

    • File transfer

    • Email

    • Network management

    • Hypertext transfer


Cs412 introduction to computer networking telecommunication

Figure 3-14 from Forouzan’s 2/e

Summary of Layer Functions

The McGraw-Hill Companies, Inc., 1998

WCB/McGraw-Hill


Tcp ip reference model

TCP/IP Reference Model

  • Goals

    • Internetworking

    • Fault tolerance

    • Flexible architecture

  • Four layers of TCP/IP Reference Model

    • Host-to-network layer

    • Internet layer

    • Transport layer

    • Application layer


Internet layer

Internet Layer

  • Packet-switching, connectionless

  • Packets injected to network

    • Independent travel

    • Out-of-order arrival

  • Analogy

    • Mail system

  • IP (Internet Protocol)

    • Packet routing

    • Congestion control


Transport layer3

Transport Layer

  • Two end-to-end protocols

    • UDP (User Datagram Protocol)

    • TCP (Transmission Control Protocol)

  • UDP (User Datagram Protocol)

    • Unreliable, connectionless

    • Widely used for

      • client-server type request-reply queries

      • speech, video


Transport layer4

Transport Layer

  • TCP

    • Reliable connection-oriented

    • Incoming byte stream (form application layer) is fragmented into discrete messages and passed onto internet layer

    • Message is reassembled at destination

    • Flow control

    • Analogy

A

B

Pipe


Applications and host to network layers

Applications and Host-to-Network Layers

  • Application layer

    • No session and presentation layers

    • TELNET, FTP, SMTP, DNS, NNTP, HTTP  

  • Host-to-network layer

    • Host has to connect to to the network using some protocol so it can send IP packets


Initial tcp ip protocols and networks

Initial TCP/IP Protocols and Networks


Osi and tcp ip models

OSI and TCP/IP Models

  • Correspondence

    OSITCP/IP

Application

Application

7

6

5

4

3

2

1

Presentation

Session

Transport

Transport

Network

Internet

Data Link

Host-to-Network

Physical


Osi and tcp ip models1

OSI and TCP/IP Models

  • Similarities

    • Stack of independent protocols

    • Layer functionality

    • Transport layer 

    • Application layer


Differences between osi and tcp ip models

Differences between OSI and TCP/IP Models

  • OSI

    • Distinction between services, interfaces, and protocols(perhaps the biggest contribution)

    • Better Protocol-Hidden

    • Model first, then protocols

      • Pro: No bias, more general

      • Con: Designers did not have

        • much experience with the subject

        • a good idea of which functionality to put in which layer

    • No thought given to internetworking

    • 7 layers

    • Communication

      • Connection-Oriented and connectionless in network layer

      • Only connection-oriented in transport layer


Differences between osi and tcp ip models1

Differences between OSI and TCP/IP Models

  • TCP/IP:

    • No clear distinction between services, interfaces, and protocols

    • Worse protocol-hidden

    • Protocol first, then model

      • Pro: Protocols fit model perfectly

      • Con: Model does not fit any other protocol stacks(not general)

    • 4 layers

    • Communication

      • Connectionless in network layer

      • Both in transport layer (good for request-response protocols)


Summary of reference models

Summary of Reference Models

  • OSI

    • OSI model exceptionally useful for discussing computer networks

    • OSI protocols not popular

  • TCP/IP

    • TCP/IP model practically nonexistent

    • TCP/IP protocols widely used

  • Modified framework is used in the text


Summary of reference models1

Summary of Reference Models

  • Modified framework is used in the text


Cs412 introduction to computer networking telecommunication

Figure 2.3Peer-to-peer processes


Cs412 introduction to computer networking telecommunication

Figure 2.4An exchange using the Internet model


Cs412 introduction to computer networking telecommunication

Figure 2.5Physical layer


Cs412 introduction to computer networking telecommunication

Note:

The physical layer is responsible for transmitting individual bits from one node to the next.


Cs412 introduction to computer networking telecommunication

Figure 2.6Data link layer


Cs412 introduction to computer networking telecommunication

Note:

The data link layer is responsible for transmitting frames from one node to the next.


Cs412 introduction to computer networking telecommunication

Figure 2.7Node-to-node delivery


Cs412 introduction to computer networking telecommunication

Example 1

In Figure 2.8 a node with physical address 10 sends a frame to a node with physical address 87. The two nodes are connected by a link. At the data link level this frame contains physical addresses in the header. These are the only addresses needed. The rest of the header contains other information needed at this level. The trailer usually contains extra bits needed for error detection


Cs412 introduction to computer networking telecommunication

Figure 2.8Example 1


Cs412 introduction to computer networking telecommunication

Figure 2.9Network layer


Cs412 introduction to computer networking telecommunication

Note:

The network layer is responsible for the delivery of packets from the original source to the final destination.


Cs412 introduction to computer networking telecommunication

Figure 2.10Source-to-destination delivery


Cs412 introduction to computer networking telecommunication

Example 2

In Figure 2.11 we want to send data from a node with network address A and physical address 10, located on one LAN, to a node with a network address P and physical address 95, located on another LAN. Because the two devices are located on different networks, we cannot use physical addresses only; the physical addresses only have local jurisdiction. What we need here are universal addresses that can pass through the LAN boundaries. The network (logical) addresses have this characteristic.


Cs412 introduction to computer networking telecommunication

Figure 2.11Example 2


Cs412 introduction to computer networking telecommunication

Figure 2.12Transport layer


Cs412 introduction to computer networking telecommunication

Note:

The transport layer is responsible for delivery of a message from one process to another.


Cs412 introduction to computer networking telecommunication

Figure 2.12Reliable process-to-process delivery of a message


Cs412 introduction to computer networking telecommunication

Example 3

Figure 2.14 shows an example of transport layer communication. Data coming from the upper layers have port addresses j and k (j is the address of the sending process, and k is the address of the receiving process). Since the data size is larger than the network layer can handle, the data are split into two packets, each packet retaining the port addresses (j and k). Then in the network layer, network addresses (A and P) are added to each packet.


Cs412 introduction to computer networking telecommunication

Figure 2.14Example 3


Cs412 introduction to computer networking telecommunication

Figure 2.15Application layer


Cs412 introduction to computer networking telecommunication

Note:

The application layer is responsible for providing services to the user.


Cs412 introduction to computer networking telecommunication

Figure 2.16Summary of duties


Example networks

Example Networks

  • The Internet

  • Connection-Oriented Networks

    • X.25, Frame Relay, and ATM

  • Ethernet

  • Wireless LANs: 802:11


Cs412 introduction to computer networking telecommunication

Standards and Standards Organizations

  • Why standards?

  • Categories

    • de facto

    • de jure

  • Organizations

    • ITU-T (formerly CCITT)

    • ISO

    • ANSI

    • IEEE

    • IETF

    • ATM Forum


  • Login