1 COMPUTER NETWORKS NETWORK ARCHITECTURE AND PROTOCOLS
2 The Need for Standards Computers have different architectures, store data in different formats and communicate at different rates Agreeing on a particular standard is difficult Defacto Standards Standards that exist by virtue of wide spread use Products consistent with these standards often have a large market Standards adopted by Agencies Step 1 Submit proposal to be considered by an agency Step 2 If proposal has merit and wide spread acceptance, agency make suggestions for modifications to originators Step 3 After rounds of suggestions and modifications the proposal is adopted or refused
3 Network Architectures The task of designing a communication network is too complex to be handled as a monolithic unit. An alternative, a structured approach. Divide communication task into manageable parts. Need to describe the communication functions in terms of an architecture. A network architecture defines the relationship and interactions between network services and functions through common interfaces and protocols.
4 What is a Protocol? A protocol is a set of mutually agreed upon rules that regiment interactions between communicating entities. The key elements of a protocol are: Syntax defines tstructure of information communicated Semantics defines the meaning of the exchanged information, including control and signaling information Timing defines the time at which data should be exchanged. Key elements define WHAT is comunicated, HOW it is communicated, and WHEN it is communicated.
5 NETWORK ARCHITECTURE LAYERING
6 OSI Reference Model Layered Architecture of Computer Networks International Organization for Standardization (ISO) developed Open Systems Interconnection (OSI) Reference Model that characterizes and standardizes the internal functions of a communication system Model provides a framework for the development protocols for computer communication Defines the rules and conventions for various functions within each layer Specifies the general relations among these functions. Determines the constraints on the types of functions and their relations.
7 Layered Architecture Model describes the architecture in terms of abstract layers Boundaries between adjacent layers are called interfaces Each layer performs a related subset of functions required for communication, and adds value to the services provided by lower layers. Layer N relies on services of layer N-1 to provide a service to layer N+1 Service required from lower layer is independent of how that service is implemented Information and complexity hiding
8 Why Layering? Monolithic non-layered architectures are costly, inflexible, and soon obsolete Layering simplifies the design, implementation and testing Layering provides flexibility for modifying and evolving protocols and services without having to change layers below Protocol in each layer can be designed separately from those in other layers
9 ISO/OSI Reference Model The ISO reference model defines seven layers: Application Layer, Presentation Layer, Session Layer, Transport Layer, Network Layer, Data Link Layer, and Physical Layer.
10 ISO/OSI Reference Model Exist only in Hosts Host Application Presentation Session Host Application Presentation Session Transport Router Router Transport Network Network Network Network Exist in Hosts and Routers Data Link Physical Data Link Physical Data Link Physical Data Link Physical Communication Medium
11 Layers, Services & Protocols Each layer operates according to a protocol to provide a service to the layer above Logically, each layer communicates directly with its peer A peer is the communication entity residing at the same layer in the other communication system Physically, each layer communicates with the layers directly above it and below it
12 ISO/OSI Reference Model Host Host Application Application Presentation Presentation Session Session Transport Router Router Transport Network Network Network Network Data Link Data Link Data Link Data Link Physical Physical Physical Physical Communication Medium
13 ISO/OSI Refrence Model Data H Data H Data H Data H Data H Data T Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer
14 NETWORK ARCHITECTURE ISO/OSI LAYERS
15 ISO/OSI Physical Layer Transmission of raw bits, 0/1, over a communication medium
16 Physical Layer Characteristics and Functions Transmission Medium Twisted-pairs, Coaxial cable, Optical fiber, Radio, Satellite, Infrared, Aspects of a communications link Mechanical Cable, Wires, Connectors, Pins,... Electrical and Optical Interfacing, Modulation, Data Encoding, Signal Strength, Voltage levels, Clock Recovery, Functional and Procedural Activation, Maintenance and Deactivation of physical links
17 Data Link Layer Functions Transfers frames across direct connections between two adjacent nodes. Transform an unreliable physical link into a reliable logical link Error free communication over a single link between adjacent nodes Speed matching between senders and receivers Framing
18 Data Link Layer The DLL is composed of two Sub-Layers Logical Link Control (LLC) Medium Access Control (MAC) Network LLC MAC Physical Data Link Layer Architecture
19 Medium Access Control (MAC) Contention occurs, when two or more nodes attempt to access a shared medium at the same time Rules must be in place to regiment access The MAC sublayer defines the rules for accessing the medium Common MAC Schemes include;: Random Access Carrier Sense Multiple Access (CSMA) CSMA, with Collision Detection (CSMA/CD) CSMA, with Collision Avoidance (CSMA/CA) Token Passing Reservation
20 LLC Sublayer Main Functions Framing Groups bits into frames, using a header and a trailer Flow Control Prevent sender from overwhelming the receiver s buffers Error Control Detecting and recovering from bit errors Single Error Detected Retransmission Double Error Undetected Retransmission LLC LLC LLC LLC Even Parity Even Parity
21 Network Layer Network Layer: Data transmission and delivery between hosts Controls access to the network Provides routing of packets within the network Manages contention and bottlenecks within the network Data Link Layer: Error free communication over a single link between adjacent nodes Speed matching between senders and receivers Framing
22 Network Layer Main Functions The network layer provides the functional and procedural means of transferring packet data units from a source to a destination functions Basic Network Layer functions include: Addressing Network devices must be assigned network addresses for identification Routing: Network nodes jointly execute a routing algorithm to determine shortest paths between traffic sources and destinations Packet Forwarding Transfer packets across a routing path Congestion Control To mitigate the impact of traffic surges
23 Transport Layer Transport layer supports required functions to enable communications between end systems. Main functions often performed include: Naming: used to differentiate between different communicating processes Multiplexing and Demultiplexing: TL multiplexes data, received from many local application programs, into as a single data stream before sending it TL demultiplexes an incoming stream of data, and directs each data packet to the appropriate recipient application process. Connection Management for Call Setup and Teardown Segmentation and Reassembly To meet the length requirement of the physical network Reliability and Flow Control To deal with packet error and packet loss, delivery out-of-order, and packet duplication
24 Session Layer The main function of a session layer is to establish and maintains a session between two end-users Dialog management can be full duplex or half Duplex The session layer establishes the connection in conjunction with the application A video session may have multiple transport connections for Video audio, and textual Data In case of connection disruption during large file transfers, SL enables the communication resume form synchronization points
25 Presentation Layer Different computers have different ways of representing the same information The presentation layer establishes a common ground of communication Data compression Decreasing as much as possible the amount of bits used to represent information Security If an un-authorized person intercepts the message, it is unintelligible
26 Application Layer Application Layer: Provides services that are frequently required by applications: Typical application layers File Transfer Protocol (FTP) Hypertext Transfer Protocol (HTTP) Telnet
27 NETWORK ARCHITECTURE PEER-TO-PEER COMMUNICATION
28 Peer-to-Peer Communication Protocols Layer-N in one system interacts with Layer-N in another system to provide service to Layer-( N+1) The entities comprising the corresponding layers on different machines are called peer processes. The communicating entities use a set of rules and conventions called the layer-n Protocol. Layer-N peer processes communicate by exchanging Protocol Data Units (PDUs)
29 Layer N Peer-To-Peer Protocol Layer N Interface Protocol SAP Service Access Point SAP Interface Protocol Layer N-1 End System Peer-To-Peer Protocol Layer N-1 End System
30 Peer-to-Peer Communication Communication between peer processes is virtual and actually indirect Layer-N+1transfers information by invoking the services provided by Layer-N Services are available at Service Access Points (SAP) Each layer passes data and control information to the layer below it until the physical layer is reached and transfer occurs The data passed to the layer below is called a Service Data Unit (SDU) SDU s are encapsulated in PDU s 30
31 Protocol Data Unit A layer accepts a Service Data Unit and adds Protocol Control Information to form a Protocol Data Unit. Layer N+1 Layer N+1 NPCI SAP NPCI SAP NPCI NSDU NPDU Layer N Peer-to-peer communication NPCI NSDU NPDU Layer N
32 Interface Data Unit A set of Interface Data and its associated ICI makes an IDU, the data unit passed across abstract interfaces at the Service Access Point. IDU SAP ICI Int. Data ICI Int. Data ICI Int. Data PCI SDU PCI SDU PDU
33 Headers & Trailers Data Application AH Data Application Presentation PH AH Data Presentation Session SH PH AH Data Session Transport TH SH PH AH Data Transport Network NH TH SH PH AH Data Network Data Link DH NH TH SH PH AH Data CRC Data Link Physical Physical 33
34 ISO/OSI Service Primitives Interactions between adjacent layers are managed by communication primitives. A primitive initiates an action or reports a result. These primitives can occur at various instances of the dialogue.
35 ISO/OSI Service Primitives Four basic primitives are defined: Service.Request(): Invokes the services of the lower layer and passes the needed parameters. Service.Indication(): Advises the higher layer of the requested service. Service.Response(): Used to reply to an indication issued by the lower layer. Service.Confirmation(): Used to acknowledge the completion of a request previously invoked by a higher layer.
36 ISO/OSI Service Types Three types of service: Confirmed Service Involves all four primitives Unconfirmed Service Involves only Service.Request() and Service.Indication() primitives. Acknowledgment (Service.Response() and Service.Confirm()) are omitted. Provider Initiated Service Used by the network to signal special conditions, involves only Service.Indication() primitive.
37 ISO/OSI Confirmed Service SAP SAP Request Indication Confirm Response End System End System Time
38 ISO/OSI Unconfirmed Service SAP SAP Request Indication End System End System Time
39 ISO/OSI Provider Initiated Service SAP Provider SAP Indication Indication End System End System Time
40 Segmentation & Reassembly A layer may impose a limit on the size of a data segment that it can transfer for Thus, a Layer-N SDU may be too large to be handled as a single unit by Layer-N-1 The SDU is segmented into multiple PDUs Segmentation n-sdu n-pdu n-pdu n-pdu Reassembly n-sdu n-pdu n-pdu n-pdu
41 Multiplexing Layer N+1 Entity Layer N+1 Entity Layer N+1 Entity Layer N+1 Entity N-sap N-sap N-PDU N-SAP N-sap N-SDU H Layer N Entity Layer N Entity H N-SDU N-PDU Sharing of Layer-N service by multiple Layer-N+1 users Multiplexing ID is required in each PDU to determine
42 NETWORK ARCHITECTURE INTERNET ARCHITECTURE
43 Internet Design Philosophy The approach resulted from extensive research and practical experience of ARPANET, currently the Internet The fundamental principle of the architecture Communication between local and remote processes can be accomplished by first identifying the remote host and then identifying the remote process within the remote host.
44 Internet Design The actions of identifying the network and the remote process can be handled independently. The task of the network is reduced mainly to routing data between hosts. The network need not be concerned with how the data is directed to the remote process within the host.
45 Internet Layers Based on the above concept, the architecture was conceived as a hierarchical ordering of protocols that can be organized into four layers: Application layer, Transport layer, the Internet layer, and Network access layer. Higher layers may bypass an adjacent layer and directly use the services of a lower layer.
46 Internet Protocol Architecture Process Telnet FTP HTTP SNMP ToD Host-to-Host (Transport) Transmission Control Protocol (TCP) User Datagram Protocol (UDP) Internet (Network) Internet Protocol (IP) Internet Control Message Protocol (ICMP) Network Interface Subnetwork A Subnetwork B
47 ISO/OSI Internet Correspondence ISO/OSI Internet Application Presentation Process Session Transport Network Data Link Physical Host-to-Host Internet Network Access
48 Internet Addressing Concept Host A Host B Port TCP Logical Transport Connection TCP IP Network Access Protocol Physical Network IP Address Physical Address Router IP Network Access Protocol Physical IP Net 1 Net 2 NAP 1 NAP 2
49 Internet Architecture The IP network layer provides a simple, best effort, datagram service May not be reliable TCP supports reliable data delivery Performance enhancement for a variety of applications: Telnet, FTP, HTTP, etc Decision does not impact other applications, if UDP can be used Everything else is implemented at application level
50 Internet Architecture Application R O B U S T FRAGILE Internet Protocol Network Physical
51 Summary Introduced the concept of a protocol Introduced the main network architectures Discussed future trends of communication networks Revisited switching techniques
Communication Networks MAP-TELE 2011/12 José Ruela Network basic mechanisms Network Architectures Protocol Layering Network architecture concept A network architecture is an abstract model used to describe
Protocol Architecture ed Protocol Architectures OSI Reference Model TCP/IP Protocol Stack Need for Protocols The task of exchanging information between devices requires a high degree of cooperation between
Protocols and Architecture Protocol Architecture. Layered structure of hardware and software to support exchange of data between systems/distributed applications Set of rules for transmission of data between
A Layered Approach to Computer Networks Physical Layer Data Link Layer Network Layer Transport Layer Session Layer Presentation Layer Application Layer Different layer of abstraction Different error control
1 Network Reference Models - OSI Reference Model - A computer network connects two or more devices together to share information and services. Multiple networks connected together form an internetwork.
The Purpose of ing CSCI 362 Computer and Security Introduction to ing Goals: Remote exchange and remote process control. A few desirable properties: Interoperability, Flexibility, Geographical range, Scalability,
Computer Networks CS321 Dr. Ramana I.I.T Jodhpur Dr. Ramana ( I.I.T Jodhpur ) Computer Networks CS321 1 / 22 Outline of the Lectures 1 Introduction OSI Reference Model Internet Protocol Performance Metrics
Chapter 1: Introduction Professor of CIS Columbus, OH 43210 Jain@cse.ohio-state.edu http://www.cse.ohio-state.edu/~jain/cis677-98/ 1B-1 Data Communication vs Networking q Communication: Two Nodes. Mostly
Introduction Computer Network. Interconnected collection of autonomous computers that are able to exchange information No master/slave relationship between the computers in the network Data Communications.
Objectives of Lecture Network Architecture Show how network architecture can be understood using a layered approach. Introduce the OSI seven layer reference model. Introduce the concepts of internetworking
524 Computer Networks Section 1: Introduction to Course Dr. E.C. Kulasekere Sri Lanka Institute of Information Technology - 2005 Course Outline The Aim The course is design to establish the terminology
The OSI Model and the TCP/IP Protocol Suite To discuss the idea of multiple layering in data communication and networking and the interrelationship between layers. To discuss the OSI model and its layer
Module 1 Introduction Lesson 2 Layered Network Architecture Specific Functional Objectives On Completion of this lesson, the students will be able to: State the requirement for layered approach Explain
What is CSG150 about? Fundamentals of Computer Networking Guevara Noubir email@example.com CSG150 Understand the basic principles of networking: Description of existing networks, and networking mechanisms
Overview Dipl.-Ing. Peter Schrotter Institute of Communication Networks and Satellite Communications Graz University of Technology, Austria Fundamentals of Communicating over the Network Application Layer
Chapter 2: Communicating over the 51 Protocol Units and Encapsulation For application data to travel uncorrupted from one host to another, header (or control data), which contains control and addressing
ISO OSI Reference Model for Layers CS 194: Distributed Systems Communication Protocols, RPC Computer Science Division Department of Electrical Engineering and Computer Sciences University of California,
CSE 123 Computer Networks Fall 2009 Lecture 2: Protocols & Layering Today What s a protocol? Organizing protocols via layering Encoding layers in packets The OSI & Internet layering models The end-to-end
Lecture 2: Protocols and Layering CSE 123: Computer Networks Stefan Savage Last time Bandwidth, latency, overhead, message size, error rate Bandwidth-delay product Delay Bandwidth High-level run through
Course Outline: Fundamental Topics System View of Network Security Network Security Model Security Threat Model & Security Services Model Overview of Network Security Security Basis: Cryptography Secret
Basic Networking Concepts 1. Introduction 2. Protocols 3. Protocol Layers 4. Network Interconnection/Internet 1 1. Introduction -A network can be defined as a group of computers and other devices connected
Communication Networks MAP-TELE 2011/12 José Ruela Network basic mechanisms Introduction to Communications Networks Communications networks Communications networks are used to transport information (data)
PART OF THE PICTURE: The / Communications Architecture 1 PART OF THE PICTURE: The / Communications Architecture BY WILLIAM STALLINGS The key to the success of distributed applications is that all the terminals
Topics Use of networks Network structure Implementation of networks Computer Networks Introduction Let s Get Started! Networking today: Where are they? Powerful computers are cheap Networks are everywhere
What Is an Internetwork? An internetwork is a collection of individual networks, connected by intermediate networking devices, that functions as a single large network. Internetworking refers to the industry,
OSI OPEN SYSTEMS OSI - Open Systems Interconnection INTERCONNECTION OVERVIEW OF PROTOCOL LAYERING AND OSI MODEL OF NETWORK STACKS Peter R. Egli INDIGOO.COM 1/8 Contents 1. Layering model 2. The 7 layers
Expert Reference Series of White Papers The OSI Model: Understanding the Seven Layers of Computer Networks 1-800-COURSES www.globalknowledge.com The OSI Model: Understanding the Seven Layers of Computer
SC250 Computer Networking I Architecture and Performance of the Internet Prof. Matthias Grossglauser School of Computer and Communication Sciences EPFL http://lcawww.epfl.ch 1 Today's Objectives Understanding
The OSI Model and the TCP/IP Protocol Suite - the OSI model was never fully implemented. - The TCP/IP protocol suite became the dominant commercial architecture because it was used and tested extensively
1 Local & Metropolitan Area Networks ACOE322 Lecture 2 Medium Access Control and Logical Link Control 1 Overview The architecture of a LAN is best described in terms of a layering of protocols that organize
CCNA R&S: Introduction to Networks Chapter 5: Ethernet 22.214.171.124 Introduction The OSI physical layer provides the means to transport the bits that make up a data link layer frame across the network media.
CPS221 Lecture: Layered Network Architecture Objectives last revised 9/10/12 1. To discuss the OSI layered architecture model 2. To discuss the specific implementation of this model in TCP/IP Materials:
Ethernet Babak Kia Adjunct Professor Boston University College of Engineering ENG SC757 - Advanced Microprocessor Design Ethernet Ethernet is a term used to refer to a diverse set of frame based networking
Network Models OSI vs. TCP/IP Network Models Using a formal model allows us to deal with various aspects of Networks abstractly. We will look at two popular models OSI reference model TCP/IP model Both
COMMUNICATION NETWORKS WITH LAYERED ARCHITECTURES Gene Robinson E.A.Robinsson Consulting 972 529-6395 ROB1200@aol.com 9 March 1999 IEEE802 N-WEST STANDARDS MEETING FOR BROADBAND WIRELESS ACCESS SYSTEMS
Overview of TCP/IP System Administrators and network administrators Why networking - communication Why TCP/IP Provides interoperable communications between all types of hardware and all kinds of operating
Local Area What s a LAN? A transmission system, usually private owned, very speedy and secure, covering a geographical area in the range of kilometres, comprising a shared transmission medium and a set
The OSI Model and the TCP/IP Protocol Suite Pritee Parwekar ANITS 1 To study To discuss the idea of multiple layering in data communication and networking and the interrelationship between layers. To discuss
1 Data communication principles, types and working principles of modems, Network principles, OSI model, functions of data link layer and network layer, networking components, communication protocols- X
Network-Oriented Software Development Course: CSc4360/CSc6360 Instructor: Dr. Beyah Sessions: M-W, 3:00 4:40pm Lecture 2 Topics Layering TCP/IP Layering Internet addresses and port numbers Encapsulation
Network Security Internet not originally designed with (much) security in mind original vision: a group of mutually trusting users attached to a transparent network Security considerations in all layers!
FIREWALLS & NETWORK SECURITY with Intrusion Detection and VPNs, 2 nd ed. Chapter 2 An Introduction to Networking Learning Objectives Upon completion of this chapter, you should be able to: Describe the
DATA COMMUNICATION (Basics of data communication, OSI layers.) K.K.DHUPAR SDE (NP-II) ALTTC ALTTC/NP/KKD/Data Communication 1 Data Communications History 1838: Samuel Morse & Alfred Veil Invent Morse Code
Data Communication Networks and Converged Networks The OSI Model and Encapsulation Layer traversal through networks Protocol Stacks Converged Data/Telecommunication Networks From Telecom to Datacom, Asynchronous
BCS THE CHARTERED INSTITUTE FOR IT BCS HIGHER EDUCATION QUALIFICATIONS BCS Level 5 Diploma in IT COMPUTER NETWORKS Friday 2 nd October 2015 Morning Answer any FOUR questions out of SIX. All questions carry
DATA COMMUNICATION AND NETWORKS 1. Define the term Computer Networks. A Computer network is a number if computers interconnected by one or more transmission paths. The transmission path often is the telephone
Chapter 2 - The TCP/IP and OSI Networking Models TCP/IP : Transmission Control Protocol/Internet Protocol OSI : Open System Interconnection RFC Request for Comments TCP/IP Architecture Layers Application
Data Communication Networks Introduction M. R. Pakravan Department of Electrical Engineering Sharif University of Technology Data Networks 1 Introduction The course introduces the underlying concepts and
Computer Networks Ethernet Hubs and Switches Based on Computer Networking, 4 th Edition by Kurose and Ross Ethernet dominant wired LAN technology: cheap $20 for NIC first widely used LAN technology Simpler,
Computer Network Layers CIS748 Class Notes Alex S. 1 The Layers Normally, the task of communication from computer to computer is broken up into layers. Each device attached to the network has a corresponding
Overview: Network Introduction what is a computer network? digital transmission components of a computer network network hardware network software What is a computer network? an interconnected collection
Introduction To Computer Networking Alex S. 1 Introduction 1.1 Serial Lines Serial lines are generally the most basic and most common communication medium you can have between computers and/or equipment.
ELEC3030 Computer Networks Professor Sheng Chen: Building 86, Room 1021 E-mail: firstname.lastname@example.org Download lecture slides from: http://www.ecs.soton.ac.uk/ sqc/el336/ or get them from Course Office (ECS
Transport Layer Protocols Version. Transport layer performs two main tasks for the application layer by using the network layer. It provides end to end communication between two applications, and implements
Lecture 28: Internet Protocols 15-110 Principles of Computing, Spring 2016 Dilsun Kaynar, Margaret Reid-Miller, Stephanie Balzer Reminder: Exam 2 Exam 2 will take place next Monday, on April 4. Further
Understand the OSI Model Part 2 Lesson Overview In this lesson, you will learn information about: Frames Packets Segments TCP TCP/IP Model Well-known ports for most-used purposes Anticipatory Set Review
Link Layer 5.1 Introduction and services 5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet 5.6 Hubs and switches 5.7 PPP 5.8 Link Virtualization: and
A PPENDIX L TCP/IP and OSI William Stallings Copyright 2010 L.1 PROTOCOLS AND PROTOCOL ARCHITECTURES...2! L.2 THE TCP/IP PROTOCOL ARCHITECTURE...5! TCP/IP Layers...5! TCP and UDP...7! Operation of TCP/IP...7!
Agenda Distributed System Structures CSCI 444/544 Operating Systems Fall 2008 Motivation Network structure Fundamental network services Sockets and ports Client/server model Remote Procedure Call (RPC)
IT4405 Computer Networks (Compulsory) INTRODUCTION This course provides a comprehensive insight into the fundamental concepts in data communications, computer network systems and protocols both fixed and
SFWR 4C03: Computer Networks & Computer Security Jan 3-7, 2005 Lecturer: Kartik Krishnan Lecture 1-3 Communications and Computer Networks The fundamental purpose of a communication network is the exchange
Networking Test 4 Study Guide True/False Indicate whether the statement is true or false. 1. IPX/SPX is considered the protocol suite of the Internet, and it is the most widely used protocol suite in LANs.
Internet Packets Packets at the network layer level are called datagrams They are encapsulated in frames for delivery across physical networks Frames are packets at the data link layer Datagrams are formed
Networking, its all about the apps! CSIS 3230 Chapter 2: Layer Concepts Chapter 5.4: Link Layer Addressing Networks exist to support apps Web Social ing Multimedia Communications Email File transfer Remote
Indian Institute of Technology Kharagpur TCP/IP Part I Prof Indranil Sengupta Computer Science and Engineering Indian Institute of Technology Kharagpur Lecture 3: TCP/IP Part I On completion, the student
CHAPTER 32 Open System Interconnection (OSI) Protocols Background The Open System Interconnection (OSI) protocol suite is comprised of numerous standard protocols that are based on the OSI reference model.
What s the Internet? PC server laptop cellular handheld access points wired s connected computing devices: hosts = end systems running apps communication s fiber, copper, radio transmission rate = bandwidth
Industrial Networks & Databases - Device Bus - - Field Bus - - Data Bus - Recall MODBUS protocol is a messaging structure used to set up master/client type communications with slaves/servers between intelligent
Lecture 7: Distributed Operating Systems A Distributed System 7.2 Resource sharing Motivation sharing and printing files at remote sites processing information in a distributed database using remote specialized
Networking Primer* *caveat: this is just a brief and incomplete introduction to networking to help students without a networking background learn Network Security. How do I get to www.randomsite.com? Local
Local Area Networks Ethernet 802.3 LAN - 7-1 Local Area Networks (Lokale Netze) Wide Area Network LAN - 7-2 Local Area Networks What is a LAN? Multiple systems attached to an often shared medium high total
CHAPTER 20 OSI Protocols Background In the early days of intercomputer communication, networking software was created in a haphazard, ad hoc fashion. When networks grew sufficiently popular, the need to