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Slide 1: Living in a Network Centric World Network Fundamentals – Chapter 1 ITE I Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 1
Slide 2: Objectives Describe how networks impact our daily lives. Describe the role of data networking in the human network. Identify the key components of any data network. Identify the opportunities and challenges posed by converged networks. Describe the characteristics of network architectures: fault tolerance, scalability, quality of service and security. Install and use IRC clients and a Wiki server. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 2
Slide 3: How Networks Impact Daily Life Early data networks were limited to exchanging character-based information between connected computer systems. Current networks have evolved to carry voice, video streams, text, and graphics between many different types of devices Data networks that were once the transport of information from business to business have been repurposed to improve the quality of life for people everywhere. –Decide what to wear using online current weather conditions. –Find the least congested route to your destination, displaying weather and traffic video from webcams. –Check your bank balance and pay bills electronically. –Receive and send e-mail, or make an Internet phone call, at an Internet cafe over lunch. –Obtain health information and nutritional advice from experts all over the world, and post to a forum to share related health or treatment information. –Download new recipes and cooking techniques to create a spectacular dinner. –Post and share your photographs, home videos, and experiences with friends or with the world. The Global Community-national borders, geographic distances, and physical limitations become less relevant ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 3
Slide 4: How Networks Impact Daily Life Instant messaging (IM) is a form of real-time communication between two or more people based on typed text. IM also incorporates features such as file transfer, voice, and video communication The form of communication that IM uses is called realtime communication. Collaboration Tools Without the constraints of location or time zone, individuals connected to a shared system can speak to each other, share text and graphics, and edit documents together. The audio file is placed on a website (or blog or wiki) where others can download it and play the recording on their computers, laptops, and iPods. Weblogs (Blogs) are web pages that are easy to update and edit. (Unlike commercial websites) Wikis--Wikis are web pages that groups of people can edit and view together. Whereas a blog is more of an individual, personal journal, a wiki is a group creation. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 4
Slide 5: How Networks Impact Daily LifeElearning Courses delivered using network or Internet resources are often called online learning experiences, or e-learning. Traditional learning methods provide primarily two sources of expertise from which the student can obtain information: the textbook and the instructor. In contrast, online courses can contain voice, data, and video, and are available to the students at any time from any place. Online courseware and delivery offer many benefits to businesses. Among the benefits are: ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 5
Slide 6: How Networks Impact Daily Life Initially, data networks were used by businesses to internally record and manage financial information, customer information, and employee payroll systems. Intranets, private networks in use by just one company, enable businesses to communicate and perform transactions among global employee and branch locations. Companies develop extranets, or extended internetworks, to provide suppliers, vendors, and customers limited access to corporate data to check order status, inventory, and parts lists. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 6
Slide 7: How Networks Impact Daily Life The ways communication over a network supports the way we play preview the actual destinations before making a trip preview or view motion pictures, read entire books and download material for future offline access. online games, collaboration services, Online markets and auction sites provide the opportunity to buy, sell and trade all types of merchandise. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 7
Slide 8: Data Networking Role, Components, and Challenges Basic characteristics of communication Before beginning to communicate with each other, we establish rules or agreements to govern the conversation. These rules, or protocols, must be followed in order for the message to be successfully delivered and understood. –An identified sender and receiver –Agreed upon method of communicating (face-to-face, telephone, letter, photograph) –Common language and grammar –Speed and timing of delivery –Confirmation or acknowledgement requirements Quality of Communication: The external factors affecting communication are related to the complexity of the network and the number of devices a message must pass through on its route to its final destination. External factors affecting the success of communication include: •The quality of the pathway between the sender and the recipient •The number of times the message has to change form •The number of times the message has to be redirected or readressed •The number of other messages being transmitted simultaneously on the communication network •The amount of time allotted for successful communication •Internal factors affecting the successful communication across the network include: •The size of the message •The complexity of the message •The importance of the message ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 8
Slide 9: Data Networking Role, Components, and Challenges These data or information networks vary in size and capabilities, but all networks have four basic elements in common: Rules or agreements to govern how the messages are sent, directed, received and interpreted. The messages or units of information that travel from one device to another A means of interconnecting these devices - a medium that can transport the messages from one device to another Devices on the network that exchange messages with each other –Switch - the most common device for interconnecting local area networks –Firewall -provides security to networks –Router - helps direct messages as they travel across a network –Wireless Router - a specific type of router often found in home networks –Cloud - used to summarize a group of networking devices, the details of which may be unimportant to the discussion at hand –Serial Link - one form of WAN interconnection, represented by the lightning bolt-shaped line ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 9
Slide 10: Network Medium Copper –Twisted pair telephone wire(Category 5 Unshielded Twisted Pair (UTP) cable) –coaxial cable Fibre –thin strands of glass or plastic that carry light signals, are another form of networking media. Wireless –Wireless media may include the home wireless connection between a wireless router and a computer with a wireless network card, the terrestrial wireless connection between two ground stations, or the communication between devices on earth and satellites. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 10
Slide 11: Protocols. Protocols are the rules that the networked devices use to communicate with each other The industry standard in networking today is a set of protocols called TCP/IP (Transmission Control Protocol/Internet Protocol). TCP/IP is used in home and business networks, as well as being the primary protocol of the Internet. It is TCP/IP protocols that specify the formatting, addressing and routing mechanisms that ensure our messages are delivered to the correct recipient. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 11
Slide 12: Example………….. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 12
Slide 13: Data Networking Role, Components, and Challenges Converged networks Multiple services-multiple networks Traditional telephone, radio, television, and computer data networks each have their own individual versions of the four basic network elements. Technology advances are enabling us to consolidate these disparate networks onto one platform - a platform defined as a converged network. The flow of voice, video, and data traveling over the same network eliminates the need to create and maintain separate networks ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 13
Slide 14: Data Networking Role, Components, and Challenges Intelligent Information Networks The convergence of the different types of communications networks onto one platform represents the first phase in building the intelligent information network This expansion has created a wider audience and a larger consumer base for whatever message, product or service can be delivered. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 14
Slide 15: Network Architecture Characteristics Four characteristics that are addressed by network architecture design Fault Tolerance A fault tolerant network is one that limits the impact of a hardware or software failure and can recover quickly when such a failure occurs. These networks depend on redundant links, or paths, between the source and destination of a message Scalability A scalable network can expand quickly to support new users and applications without impacting the performance of the service being delivered to existing users. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 15
Slide 16: Quality of Service (quality of the delivered services). Voice and live video transmissions require a level of consistent quality and uninterrupted delivery that was not necessary for traditional computer applications Security ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 16
Slide 17: Network Architecture Characteristics The Internet, in its early inception, was the result of research funded by the United States Department of Defense (DoD). Its primary goal was to have a communications medium that could withstand the destruction of numerous sites and transmission facilities without disruption of service. It only follows that fault tolerance was the focus of the effort of the initial internet work design work. Circuit Switching: In this type of connection-oriented network, once a circuit is established, even if no communication is occurring between the persons on either end of the call, it is possible to occasionally get a message that all circuits are busy and a call cannot be placed. The cost to create many alternate paths with enough capacity to support a large number of simultaneous circuits, and the technologies necessary to dynamically recreate dropped circuits in the event of a failure, led the DoD to consider other ITE 1 Chapter 6 of networks. Systems, Inc. All rights reserved. © 2006 Cisco types Cisco Public 17
Slide 18: Packet Switching The devices within the network itself are unaware of the content of the individual packets, only visible is the address of the final destination and the next device in the path to that destination. No reserved circuit is built between sender and receiver. Each packet is sent independently from one switching location to another. At each location, a routing decision is made as to which path to use to forward the packet towards its final destination. If a previously used path is no longer available, the routing function can dynamically choose the next best available path. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 18
Slide 19: Internet Architecture Characteristics The Internet, which is actually a collection of interconnected private and public networks, has a hierarchical layered structure for addressing, for naming and for connectivity services. At each level or layer of the hierarchy, individual network operators maintain peering relationships with other operators at the same level. As a result, network traffic that is destined for local or regional services does not need to traverse to a central point for distribution. Common services can be duplicated in different regions, thereby keeping traffic off the higher level backbone networks. Although there is no single organization that regulates the Internet, the operators of the many individual networks that provide Internet connectivity cooperate to follow accepted standards and protocols. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 19
Slide 20: Network Architecture Characteristics Providing Quality of Service The packet-switched network architecture does not guarantee that all packets that comprise a particular message will arrive on time, in their correct in order, or even that they will arrive at all. In most cases, when the volume of packets is greater than what can be transported across the network, devices queue the packets in memory until resources become available to transmit them. Queuing packets causes delay. If the number of packets to be queued continues to increase, the memory queues fill up and packets are dropped. ensuring QoS requires a set of techniques to manage the utilization of network resources. In order to maintain a high quality of service 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. For example, the delivery of a movie uses a relatively large amount of network resources when it is delivered continuously without interruption. Other types of service - e-mail, for example - are not nearly as demanding on the network. In one company, an administrator might decide to allocate the greatest share of the network resources to the movie, believing that this is the priority for his customers. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 20
Slide 21: Network Architecture Characteristics Appropriate QoS strategy for a given type of traffic examples of priority decisions for an organization might include: Time-sensitive communication increase priority for services like telephony or video distribution. Non time-sensitive communication decrease priority for web page retrieval or e-mail High importance to organization increase priority for production control or business transaction data. Undesirable communication decrease priority or block unwanted activity, like peer-to-peer file sharing or live entertainment. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 21
Slide 22: Network Architecture Characteristics Why networks must be secure Consequences of a network security breach could include: 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 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 22
Slide 23: Network Architecture Characteristics Basic measures to secure data networks Security measures taken in a network should: Prevent unauthorized disclosure or theft of information Prevent unauthorized modification of information Prevent Denial of Service Means to achieve these goals include: Ensuring confidentiality Maintaining communication integrityThe use of digital signatures, hashing algorithms and check sum mechanisms are ways to provide source and data integrity across a network to prevent unauthorized modification of information. Ensuring availability ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 23
Slide 24: Where are we going-Trends….. There are three major trends that are contributing to the future shape of complex information networks: Increasing number of mobile users Proliferation of network capable devices The computer is only one of many devices on today's information networks. We have a proliferation of exciting new technologies that can take advantage of available network services. The functions performed by cell phones, Personal Digital Assistants (PDAs), organizers, and pagers are converging into single hand-held devices Expanding range of services Network career Opportunities ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 24
Slide 25: IRC Clients and Wiki Server Install and use IRC clients and a Wiki server ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 25
Slide 26: ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 26