Data Networking Fundamentals Unit 7 7/2/2015 1 Modified by: Brierley.

transcript

Data Networking Fundamentals

Unit 7

04/19/231 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

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.

Terminology

Requirements for Connectivity

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

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.

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

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.

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

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.

The Internet

The OSI Model ( 7 layers)

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.

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.

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

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.

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.

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.

Data Link Layer

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

Applying the OSI Model

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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.

The OSI and TCP/IP Models

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.

Internet Protocol

Transmission Control Protocol (TCP)

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.

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.

Addressing in TCP/IP

To view your current IP information on a Windows 2000-2008, 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.

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

The OSI and TCP/IP Models

Data Networking Fundamentals Unit 7 7/2/2015 1 Modified by: Brierley.

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