Living in a Network Centric World Network Fundamentals – Chapter 1 ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 1 How Networks Impact Daily Life ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 2 Some Popular Communication Tools –Instant messaging •Real time communication between 2 or more people based on typed text –Weblogs (Blogs) •Web pages created by an individual –Wiki •web pages that groups of people can edit and view together; group creation –Podcasting •Website that contains audio files available for downloading ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 3 Networks Support the Way We Learn ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 4 Networks Support the Way We Work ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 5 Networks Support the Way We Play ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 6 Data Networking Role, Components, and Challenges ▪ Basic characteristics of communication –Rules or agreements are first established –Important information may need to be repeated –Various modes of communication may impact the effectiveness of getting the message across. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 7 Quality of Communications ▪ For data networks, as a message moves through the network, many factors can prevent the message from reaching the recipient or distort its intended meaning. These factors can be either external or internal. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 8 Data Networking Role, Components, and Challenges ▪ All networks have four basic elements in common: –Devices •Used to communicate with one another –Medium •This is how the devices are connected together –Messages •Information that travels over the medium –Rules •Governs how messages flow across network ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 9 Some Data Network Symbols ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 10 Network Connections ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 11 Applications and Services Transmission Control Protocol/Internet Protocol (TCP/IP) - industry standard in networking today; the primary protocol of the Internet today ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 12 Converged Networks ▪ A type of network that can carry voice, video & data over the same network ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 13 Network Architecture Characteristics Network Architecture - technologies that support the infrastructure and the programmed services and protocols that move the messages across that infrastructure. ▪ Characteristics addressed by network architecture design: –Fault tolerance –Scalability –Quality of service –Security ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 14 Network Architecture Characteristics ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 15 Fault-Tolerant Network Architecture ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 16 Fault-Tolerant Network Architecture ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 17 Internet Architecture ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 18 Internet Architecture ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 19 Internet Architecture ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 20 Internet Architecture ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 21 Internet Architecture ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 22 Internet Architecture ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 23 Providing QoS ▪ Congestion is caused when the demand on the network resources exceeds the available capacity. Since networks have finite resources, QoS mechanisms are needed. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 24 Providing QoS In order to maintain high QoS for applications that require it, it is necessary to prioritize which types of data packets must be delivered at the expense of other types of packets that can be delayed or dropped. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 25 Network Architecture Characteristics Selecting the appropriate QoS strategy for a given type of traffic: ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 26 Providing Network Security Some consequences of a network security breach: ▪ Network outage that prevents communications and transactions occurring, with consequent loss of business ▪ Misdirection and loss of personal or business funds ▪ Company intellectual property (research ideas, patents or designs) that is stolen and used by a competitor ▪ Customer contract details that become known to competitors or made public, resulting in a loss of market confidence in the business ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 27 Network Architecture Characteristics Basic measures to secure data networks –Ensure confidentiality through use of •User authentication •Data encryption –Maintain communication integrity through use of •Digital signatures –Ensure availability through use of •Firewalls •Redundant network architecture •Hardware without a single point of failure ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 28 Summary ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 29 ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 30 Communicating over the Network Network Fundamentals – Chapter 2 CCESC ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 31 Network Structure ▪ 3 Common Elements of Communication • message source • the channel • message destination ▪ Network (as pertained in the course) data or information networks capable of carrying many different types of communications ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 32 Message communication Data is sent across a network in small “chunks” called segments. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 33 Message communication ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 34 Network Structure ▪ Components of a network ITE PC v4.0 Chapter 1 • hardware - visible components of the network platform • software – services and processes © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 35 Network Structure ▪ End Devices and their Role in the Network –End devices form interface with human network & communications network –End devices role: client, server, both client and server ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 36 Network Structure Role of an intermediary device –Regenerate and retransmit data signals –Maintain information about what pathways exist through the network and internetwork –Notify other devices of errors and communication failures –Direct data along alternate pathways when there is a link failure –Classify and direct messages according to QoS priorities –Permit or deny the flow of data, based on security settings ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 37 Network Structure Network media - the channel over which a message travels ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 38 Network Types ▪ Local Area Networks (LANs) - A network serving a home, building or campus is considered a Local Area Network (LAN) ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 39 Network Types ▪ Wide Area Networks (WANs) - LANs separated by geographic distance are connected by a network known as a Wide Area Network (WAN) ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 40 Network Types ▪ Internet –a global mesh of interconnected networks ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 41 Network Representations ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 42 Function of Protocol in Network Communication ▪ A protocol is a set of predetermined rules used to facilitate communication over data networks ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 43 The Role of Protocols ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 44 Protocol Suites and Industry Standards A standard is a process or protocol that has been endorsed by the networking industry and ratified by a standards organization Ex: IEEE, IETF ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 45 Interaction of Protocols ▪ An example of the use of a protocol suite in network communications is the interaction between a web server and a web browser. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 46 Technology independent Protocols Many diverse types of devices can communicate using the same sets of protocols. This is because protocols specify network functionality, not the underlying technology to support this functionality. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 47 Layers with TCP/IP and OSI Model ▪ Benefits of using a layered model • assists in protocol design • fosters competition • changes in one layer do not affect other layers • provides a common language ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 48 Layers with TCP/IP and OSI Model ▪ TCP/IP Model - first layered protocol model for internetwork communications; Internet Model; definitions of the standard and the TCP/IP protocols are discussed in a public forum and publiclyavailable set of documents called Requests for Comments (RFCs) ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 49 Layers with TCP/IP and OSI Model Untouched Message Travels through the Network ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 50 Protocol Data Units and Encapsulation ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 51 Layers with TCP/IP and OSI Model ▪ Process of sending and receiving messages ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 52 Layers with TCP/IP and OSI Model ▪ Explain protocol and reference models A protocol model provides a model that closely matches the structure of a particular protocol suite. A reference model provides a common reference for maintaining consistency within all types of network protocols and services. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 53 OSI Layer Model Provides the means for end to end connectivity between individuals in the human network using data Provides for common representation transferred between Application layer of the data Provides services to the Presentation Layer to organize its dialogue and to manage data exchange Defines services to segment, transfer and reassemble the data for individual communications between the end devices Provides services to exchange the individual pieces of data over the network between identified end devices ITE PC v4.0 Chapter 1 Describe methods for exchanging data frames between devices over a common media Describe the mechanical, electrical, functional and procedural means to activate, maintain and de-activate physical – connections for bit transmission to and from a 54 network device © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public Comparing TCP/IP and OSI Model ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 55 Addressing and Naming Schemes Encapsulation headers are used to manage communication in data networks. ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 56 Addressing and Naming Schemes ▪ Describe examples of Ethernet MAC Addresses, IP Addresses, and TCP/UDP Port numbers ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 57 Addressing and Naming Schemes ▪ Explain how labels in encapsulation headers are used to manage communication in data networks ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 58 Addressing and Naming Schemes ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 59 Summary ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 60 ITE PC v4.0 Chapter 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 61
