Copyright CCNA 1 Chapter 2 Networking Fundamentals By Your Name
Copyright Objectives Networking terminology Bandwidth Networking models
Copyright Data Networks Data networking solutions –Local-area networks –Wide-area networks
Copyright Networking History
Copyright Networking Devices Equipment that connects directly to a network segment is referred to as a device. These devices are broken up into two classifications. The first classification is end-user devices. The second classification is network devices.
Copyright Network Topology Network topology defines the structure of the network. The physical topology, which is the actual layout of the wire or media, and the logical topology, which defines how the media is accessed by the hosts for sending data.
Copyright Network Protocols Protocol suites are collections of protocols that enable network communication from one host through the network to another host. A protocol is a formal description of a set of rules and conventions that govern a particular aspect of how devices on a network communicate.
Copyright LANs Operate within a limited geographic area Allow many users to access high-bandwidth media Provide full-time connectivity to local services Connect physically adjacent devices
Copyright LAN Devices
Copyright WAN Technologies Include Analog modems Integrated Services Digital Network (ISDN) Digital Subscriber Line (DSL) Frame Relay Asynchronous Transfer Mode (ATM) T (US) and E (Europe) carrier series: T1, E1, T3, E3 Synchronous Optical Network (SONET)
Copyright WAN Devices
Copyright Metropolitan-Area Networks (MANs) A MAN is a network that spans a metropolitan area such as a city or suburban area. A MAN usually consists of two or more LANs in a common geographic area.
Copyright Storage-Area Networks (SANs) A SAN is a dedicated, high-performance network used to move data between servers and storage resources. Because it is a separate, dedicated network, it avoids any traffic conflict between clients and servers.
Copyright Virtual Private Networks (VPNs) A VPN is a private network that is constructed within a public network infrastructure such as the global Internet.
Copyright Benefits of VPNs A VPN is a service that offers secure, reliable connectivity over a shared public network infrastructure such as the Internet. VPNs maintain the same security and management policies as a private network. They are the most cost-effective method of establishing a point-to-point connection between remote users and an enterprise customer's network.
Copyright VPN Types There are three main types of VPNs: Intranet VPNs Extranet VPNs Access VPNs
Copyright Intranets and Extranets Intranets are designed to permit access by users who have access privileges to the internal LAN of the organization. Extranets refer to applications and services that are Intranet based, but that use extended, secure access to external users or enterprises.
Copyright Bandwidth
Copyright Importance of Bandwidth
Copyright Digital Bandwidth Two analogies that describe digital bandwidth –Width of a pipe –Number of lanes on a highway Media bandwidth differences –Category 5 UTP – 100 meters maximum physical distance –Multimode (62.5/125um) optical fiber – 2000 meters –Modem – 56 kbps = Mbps –T1 – Mbps
Copyright Digital Bandwidth (cont.) Data throughput in relation to digital bandwidth –Factors that determine: internetworking devices, type of date being transferred, topology, number of users, user’s computer Data transfer calculation –Estimated time = size of file / bandwidth
Copyright Bandwidth Pipe Analogy
Copyright Bandwidth Highway Analogy
Copyright Bandwidth Measurements
Copyright Media Bandwidth
Copyright Digital Transfer Calculation
Copyright Digital vs. Analog Analog bandwidth is measured by how much of the electromagnetic spectrum is occupied by each signal. In digital signaling, all information is sent as bits, regardless of the kind of information it is.
Copyright Networking Models
Copyright Using Layers to Describe Communication Source, destination, and data packets –All communications originate at a source and travel to a destination. –Information that travels on a network is referred to as a data, packet, or data packet.
Copyright Using Layers to Describe Communication Media –Telephone wires (UTP) –Category 5 UTP (used for 10BASE-T Ethernet) –Coaxial cables –Optical fibers (thin glass fibers that carry light) Protocol –All devices on a network need to speak the same language. –Set of rules that makes communication both possible and more efficient.
Copyright The Purpose of the OSI Reference Model It breaks network communication into smaller, simpler parts that are easier to develop. It facilitates standardization of network components to allow multiple-vendor development and support. It allows different types of network hardware and software to communicate with each other. It prevents changes in one layer from affecting the other layers so that they can develop more quickly. It breaks network communication into smaller parts to make learning it easier to understand.
Copyright Seven Layers of the OSI Reference Model Layer 7: Application Layer 6: Presentation Layer 5: Session Layer 4: Transport Layer 3: Network Layer 2: Data link Layer 1: Physical
Copyright Why a Layered Model?
Copyright Layers with Functions
Copyright The Seven Layers of the OSI Reference Model The application (upper) layers –Layer 7: Application –Layer 6: Presentation –Layer 5: Session The data-flow (lower) layers –Layer 4: Transport –Layer 3: Network –Layer 2: Data link –Layer 1: Physical
Copyright The Application (Upper) Layers Application –User interface –Examples – Telnet, HTTP Presentation –How data is presented –Special processing, such as encryption –Examples – ASCII, EMCDIC, JPEG Session –Keeping different applications’ data separate –Examples – Operating system/application access scheduling
Copyright The Data-Flow (Lower) Layers Transport –Reliable or unreliable delivery –Error correction before transmit –Examples: TCP, UDP, SPX Network –Provide logical addressing which routers use for path determination –Examples: IP, IPX
Copyright The Lower Layers (cont.) Data link –Combines bits into bytes and bytes into frames –Access to media using MAC address –Error detection not correction –Examples: 802.3/802.2, HDLN Physical –Moves bits between devices –Specifies voltage, wire speed, and pinout cables –Examples: EIA/TIA-232, V.35
Copyright The OSI Model Application – Think of browsers. Presentation – Think of common data format. Session – Think of dialogs and conversations. Transport – Think of flow control and reliability. Network – Think of path selection, routing, and logical addressing. Data Link – Think of frames and media access control. Physical – Think of signals and media.
Copyright Peer-to-Peer Communication For data to travel from the source to the destination, each layer of the OSI model at the source must communicate with its peer layer at the destination. During this process, the protocols of each layer exchange information, called protocol data units (PDUs), between peer layers. Each layer of communication on the source computer communicates with a layer-specific PDU, and with its peer layer on the destination computer.
Copyright The TCP/IP Reference Model
Copyright TCP/IP Protocol Graph
Copyright Applications FTP – File Transfer Protocol HTTP – Hypertext Transfer Protocol SMTP – Simple Mail Transfer Protocol DNS – Domain Name System TFTP – Trivial File Transfer Protocol
Copyright OSI Model and TCP/IP Model
Copyright Use of the OSI Model in the CCNA Curriculum
Copyright Encapsulation The lower layers use encapsulation to put the protocol data unit (PDU) from the upper layer into its data field and to add headers and trailers that the layer can use to perform its function.
Copyright Names for Data at Each Layer
Copyright De-Encapsulation When the data link layer receives the frame, it does the following: –It reads the physical address and other control information provided by the directly connected peer data link layer. –It strips the control information from the frame, thereby creating a datagram. –It passes the datagram up to the next layer, following the instructions that appeared in the control portion of the frame.