CCNA 1 Chapter 2Networking Fundamentals By Your Name
Objectives • Networking terminology • Bandwidth • Networking models
Data Networks • Data networking solutions • Local-area networks • Wide-area networks
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.
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. Network Topology
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.
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
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)
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.
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. Storage-Area Networks (SANs)
Virtual Private Networks (VPNs) • A VPN is a private network that is constructed within a public network infrastructure such as the global Internet.
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.
VPN Types • There are three main types of VPNs: • Intranet VPNs • Extranet VPNs • Access VPNs
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. Intranets and Extranets
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 = 0.056 Mbps • T1 – 1.544 Mbps
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
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.
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.
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.
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.
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
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
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
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
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
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.
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.
Applications • FTP – File Transfer Protocol • HTTP – Hypertext Transfer Protocol • SMTP – Simple Mail Transfer Protocol • DNS – Domain Name System • TFTP – Trivial File Transfer Protocol
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.
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.