CCEE 454-Lecture 2.pdf

Chapter 1: Introduction to Networks Introduction to Networks v7.0 (ITN) 1.1 Networks Affect Our Lives © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2 Networking Today No Boundaries World without boundaries Global communities Human ne...

Chapter 1: Introduction to Networks Introduction to Networks v7.0 (ITN) 1.1 Networks Affect Our Lives © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2 Networking Today No Boundaries World without boundaries Global communities Human network © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 3 1.2 Network Components © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 4 Network Components Host Roles Every computer on a network is called a host or end device. Servers are computers that provide information to end devices: email servers web servers Server Description Type file server Email Email server runs email server software. Clients are computers that send Clients use client software to access email. requests to the servers to retrieve Web Web server runs web server software. information: Clients use browser software to access web pages. web page from a web server email from an email server File File server stores corporate and user files. The client devices access these files. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 5 Network Components Peer-to-Peer It is possible to have a device be a client and a server in a Peer-to-Peer Network. This type of network design is only recommended for very small networks. Advantages Disadvantages Easy to set up No centralized administration Less complex Not as secure Lower cost Not scalable Used for simple tasks: transferring files and sharing Slower performance printers © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 6 Network Components End Devices An end device is where a message originates from or where it is received. Data originates with an end device, flows through the network, and arrives at an end device. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7 Network Components Intermediary Network Devices An intermediary device interconnects end devices. Examples include switches, wireless access points, routers, and firewalls. Management of data as it flows through a network is also the role of an intermediary device, including: Regenerate and retransmit data signals. Maintain information about what pathways exist in the network. Notify other devices of errors and communication failures. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 8 Network Components Network Media Communication across a network is carried through a medium which allows a message to travel from source to destination. Media Types Description Metal wires within cables Uses electrical impulses Glass or plastic fibers Uses pulses of light. within cables (fiber-optic cable) Wireless transmission Uses modulation of specific frequencies of electromagnetic waves. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 9 1.3 Network Representations and Topologies © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 10 Network Representations and Topologies Network Representations Network diagrams, often called topology diagrams, use symbols to represent devices within the network. Important terms to know include: Network Interface Card (NIC) Physical Port Interface Note: Often, the terms port and interface are used interchangeably © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11 Network Representations and Topologies Topology Diagrams Physical topology diagrams illustrate the Logical topology diagrams illustrate devices, physical location of intermediary devices ports, and the addressing scheme of the and cable installation. network. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 12 1.4 Common Types of Networks © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 13 Common Types of Networks Networks of Many Sizes Small Home Networks – connect a few computers to each other and the Internet Small Office/Home Office – enables computer within a home or remote office to connect to a corporate network Small Home SOHO Medium to Large Networks – many locations with hundreds or thousands of interconnected computers World Wide Networks – connects hundreds of millions of computers world- wide – such as the internet Medium/Large World Wide © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 14 Common Types of Networks LANs and WANs Network infrastructures vary greatly in terms of: Size of the area covered Number of users connected Number and types of services available Area of responsibility Two most common types of networks: Local Area Network (LAN) Wide Area Network (WAN). © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 15 Common Types of Networks LANs and WANs (cont.) A LAN is a network infrastructure that spans A WAN is a network infrastructure that spans a small geographical area. a wide geographical area. LAN WAN Interconnect end devices in a limited area. Interconnect LANs over wide geographical areas. Administered by a single organization or Typically administered by one or more service individual. providers. Provide high-speed bandwidth to internal Typically provide slower speed links between LANs. devices. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 16 Common Types of Networks The Internet The internet is a worldwide collection of interconnected LANs and WANs. LANs are connected to each other using WANs. WANs may use copper wires, fiber optic cables, and wireless transmissions. The internet is not owned by any individual or group. The following groups were developed to help maintain structure on the internet: IETF ICANN IAB © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 17 Common Types of Networks Intranets and Extranets An intranet is a private collection of LANs and WANs internal to an organization that is meant to be accessible only to the organizations members or others with authorization. An organization might use an extranet to provide secure access to their network for individuals who work for a different organization that need access to their data on their network. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 18 1.5 Internet Connections © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 19 Internet Connections Internet Access Technologies There are many ways to connect users and organizations to the internet: Popular services for home users and small offices include broadband cable, broadband digital subscriber line (DSL), wireless WANs, and mobile services. Organizations need faster connections to support IP phones, video conferencing and data center storage. Business-class interconnections are usually provided by service providers (SP) and may include: business DSL, leased lines, and Metro Ethernet. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 20 Internet Connections Home and Small Office Internet Connections Connection Description Cable high bandwidth, always on, internet offered by cable television service providers. DSL high bandwidth, always on, internet connection that runs over a telephone line. Cellular uses a cell phone network to connect to the internet. Satellite major benefit to rural areas without Internet Service Providers. Dial-up an inexpensive, low bandwidth telephone option using a modem. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 21 Internet Connections Businesses Internet Connections Corporate business connections may Type of Description require: Connection Dedicated These are reserved circuits within higher bandwidth Leased Line the service provider’s network that dedicated connections connect distant offices with private voice and/or data networking. managed services Ethernet This extends LAN access technology WAN into the WAN. DSL Business DSL is available in various formats including Symmetric Digital Subscriber Lines (SDSL). Satellite This can provide a connection when a wired solution is not available. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 22 Internet Connections The Converging Network Before converged networks, an organization would have been separately cabled for telephone, video, and data. Each of these networks would use different technologies to carry the signal. Each of these technologies would use a different set of rules and standards. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 23 Internet Connections The Converging Network (Cont.) Converged data networks carry multiple services on one link including: data voice video Converged networks can deliver data, voice, and video over the same network infrastructure. The network infrastructure uses the same set of rules and standards. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 24 1.6 Reliable Networks © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 25 Reliable Network Network Architecture Network Architecture refers to the technologies that support the infrastructure that moves data across the network. There are four basic characteristics that the underlying architectures need to address to meet user expectations: Fault Tolerance Scalability Quality of Service (QoS) Security © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 26 Reliable Network Fault Tolerance A fault tolerant network limits the impact of a failure by limiting the number of affected devices. Multiple paths are required for fault tolerance. Reliable networks provide redundancy by implementing a packet switched network: Packet switching splits traffic into packets that are routed over a network. Each packet could theoretically take a different path to the destination. This is not possible with circuit-switched networks which establish dedicated circuits. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 27 Reliable Network Scalability A scalable network can expand quickly and easily to support new users and applications without impacting the performance of services to existing users. Network designers follow accepted standards and protocols in order to make the networks scalable. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 28 Reliable Network Quality of Service Voice and live video transmissions require higher expectations for those services being delivered. Have you ever watched a live video with constant breaks and pauses? This is caused when there is a higher demand for bandwidth than available – and QoS isn’t configured. Quality of Service (QoS) is the primary mechanism used to ensure reliable delivery of content for all users. With a QoS policy in place, the router can more easily manage the flow of data and voice traffic. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 29 Reliable Network There are two main types of network Network Security security that must be addressed: Network infrastructure security Physical security of network devices Preventing unauthorized access to the devices Information Security Protection of the information or data transmitted over the network Three goals of network security: Confidentiality – only intended recipients can read the data Integrity – assurance that the data has not be altered with during transmission Availability – assurance of timely and reliable access to data for authorized users © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 30