Data Networking Fundamentals Unit 7 7/2/ Modified by: Brierley

Objectives Discuss basic networking concepts - elements common to client- server Provide examples of multiple network services Describe differences between LANs, MANs, and WANs Understand the function of each layer of the OSI model Describe the purpose of protocols and recognize core protocols and addressing scheme for the TCP/IP protocol suite 7/2/ Modified by: Brierley

Terminology Standalone workstation - a workstation not connected to a network. Relies on its own hard disk for data storage and applications. A Personal computer (PC). Client - a workstation or PC connected to a network. The person whose workstation is part of a network may also be called a “client”, or more informally a “user”. Servers - store shared data and programs on their hard disks. They perform management functions - such as determining a user’s access to certain applications, data and services. Client-server – an architecture that uses a server to enable clients with sharing data storage space, networked devices and services. 7/2/ Modified by: Brierley

Terminology 7/2/ Modified by: Brierley

Requirements for Connectivity 7/2/ Modified by: Brierley

Requirements for Communications Node - any device (a server, client, printer, mobile device, etc.) that can receive messages across a network. To receive data, each node must have a unique address. Protocol – a set of rules 7/2/ Modified by: Brierley

Servers Server - A computer on the network that manages shared resources. Redundancy – Replica - Using more than one component to guard against failure. Network operating system (NOS) - software that can manage data, users, groups, security, and applications on the network. 7/2/ Modified by: Brierley

How Networks are Used The purpose of using networks is to share services - programs, data, and devices - known as resources. Network services can be categorized as follows: File services Print services Communication services Mail services Internet services Management services 7/2/ Modified by: Brierley

LANS, MANS, and WANS Local area network (LAN) - a network of computers and other devices that is limited to a relatively small area, such as a building, rooms, or office. Connectivity device - when multiple networks or multiple parts of one network need to communicate with each other, this device is used to exchange data between them, ie hubs, routers and switches. Hub – forward messages to all its connected devices. Hubs today are Legacy replaced with switches. 7/2/ Modified by: Brierley

LANS, MANS, and WANS Metropolitan area network (MAN) - a network that connects LANs between multiple buildings in a region. Wide area network (WAN) - a network that connects geographically distinct LANs, MANs, CANs, PANs – wired and/or wireless 7/2/ Modified by: Brierley

LANS, MANS, and WANS 7/2/ Modified by: Brierley

LANS, MANS, and WANS 7/2/ Modified by: Brierley

LANS, MANS, and WANS 7/2/ Modified by: Brierley

LANS, MANS, and WANS 7/2/ Modified by: Brierley

The Internet The Internet is a unique WAN in size, and diversity. It is used to: Transmit confidential information between two offices or it may transmit public information to anyone who requests it. Connect users from around the globe, the Internet relies on a hierarchical structure of connection points, just as the PSTN relies on a hierarchy of LEC and IXC switches. Connect to Internet Service Providers (ISP) – Companies that operates a network and provides consumers links to the Internet. 7/2/ Modified by: Brierley

The Internet 7/2/ Modified by: Brierley

The Internet 7/2/ Modified by: Brierley

The OSI Model ( 7 layers) 7/2/ Modified by: Brierley

Application Layer LAYER 7 Provides interfaces to software that enable applications to use network services. Application program interface (API) - A set of instructions that allows a program to interact with an operating system. 7/2/ Modified by: Brierley

Presentation Layer LAYER 6 Establishes translation between the application and the network. Data becomes formatted in a schema that identifies the application. Encryption - A mathematical schema executed by both the sender and receiver of the payload for security. 7/2/ Modified by: Brierley

Session Layer LAYER 5 Functions include: Establishing and keeping alive the communications link for the duration of the session Synchronizing the dialog between the two nodes Determining whether communications have been cut off and establish where to restart transmission 7/2/ Modified by: Brierley

Transport Layer LAYER 4 Responsible for ensuring that data is transferred from point A to point B reliably, in the correct sequence, and without errors. Handles flow control, a method of gauging the appropriate rate of transmission. Segmentation - the process “chunking up” the Payload when moving data to the network layer into smaller units. 7/2/ Modified by: Brierley

Network Layer LAYER 3 Translates network addresses into their physical counterparts and decide how to route data from the sender to the receiver. Addressing is handled at the Network layer. 7/2/ Modified by: Brierley

Data Link Layer LAYER 2 Controls communications between the Network layer and the Physical layer. Frame - a structured package for moving data that includes not only data, or "payload," but also the sender’s and receiver’s network addresses, and error checking and control information. 7/2/ Modified by: Brierley

Data Link Layer 7/2/ Modified by: Brierley

Data Link Layer 7/2/ Modified by: Brierley

Physical Layer LAYER 1 Generates and detects voltage (pulses of light) to transmit and receive signals representing data. Sets the data transmission rate and monitors data error rates. Physical network problems, cut cable, disconnected cable, improperly defined interface 7/2/ Modified by: Brierley

Applying the OSI Model 7/2/ Modified by: Brierley

Applying the OSI Model 7/2/ Modified by: Brierley

Applying the OSI Model 7/2/ Modified by: Brierley

TCP/IP Compared to the OSI Model The TCP/IP model includes the following: Layer 4 - Application layer - provides authentication and compression services, and is roughly equivalent to the Application, Presentation, and Session layers of the OSI model. Layer 3 - Transport layer - roughly corresponds to the Transport layer of the OSI model. Layer 2 - Network layer - equivalent to the Network layer of the OSI model. Layer 1 - Link layer - roughly equivalent to the Data Link and Physical layers of the OSI model. 7/2/ Modified by: Brierley

The OSI and TCP/IP Models 7/2/ Modified by: Brierley

Internet Protocol Belongs to the Network layer of the OSI model and to the Internet layer of the TCP/IP model. It provides information about how and where data should be delivered. Datagram - the IP portion of a data frame, acts as an envelope for data and contains information for routers to transmit data between networks. IP is an unreliable, connectionless protocol, which means that it does not guarantee delivery of data. 7/2/ Modified by: Brierley

Internet Protocol 7/2/ Modified by: Brierley

Transmission Control Protocol (TCP) 7/2/ Modified by: Brierley

Transmission Control Protocol (TCP) 7/2/ Modified by: Brierley

The TCP/IP Application Layer Protocols Dynamic Host Configuration Protocol (DHCP) – automatically assigns a unique Network layer (IP) address to devices that access the network. File Transfer Protocol (FTP) - sends and receive files between hosts. Hypertext Transfer Protocol (HTTP) - Enables Web browsers to issue requests to Web servers and interpret the response. 7/2/ Modified by: Brierley

The TCP/IP Application Layer Protocols Simple Mail Transfer Protocol (SMTP) - Responsible for moving messages from one mail server to another over the Internet. Telnet - a terminal emulation protocol used to log on to remote hosts to issue configuration instructions. 7/2/ Modified by: Brierley

Addressing in TCP/IP 7/2/ Modified by: Brierley

Addressing in TCP/IP To view your current IP information on a Windows , XP, Vista, 7 Windows XP Operating System: Click Start, then click Run. The Run dialog box opens. In the Open text box, type cmd, then click OK. The Command Prompt window opens. At the DOS prompt, type ipconfig /all.Your workstation’s IP address information is displayed Type exit, then press Enter to close the Command Prompt window. 7/2/ Modified by: Brierley

Addressing in TCP/IP 7/2/ Modified by: Brierley

Data Networks Summary Workstations – client computers on a network share data, programs, and devices through a central computer called a server. Servers - using a server to enable client computers to share data storage space and devices constitutes a client-server network. Reference Models OSI and TCP/IP 7/2/ Modified by: Brierley

The OSI and TCP/IP Models 7/2/ Modified by: Brierley