net 02 03_lan

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WELCOME

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MIS – 404:

Networking and Operating Systems

Department of BBA MIS

East West University

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Course Outline

1. Computer Network: IntroductionMotivationClassification: LAN, MAN, WAN

2. Network Topology: DefinitionClassification: BUS, TREE, STAR, RING, MESH, HYBRID

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Computer Network

Background of Network When there was no network

Motivation Resource Sharing

Resource Hardware Software Data/Information

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Computer Network

Definition: When a number of computers or devices are

interconnected in a single communication system

growth of number & power of computers is driving need for interconnection

also seeing rapid integration of voice, data, image & video technologies

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History of Computer Network

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History of Computer Network

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Classification

Depending upon the area coverage:

Local Area Network (LAN) Metropolitan Area network (MAN) Wide Area Network (WAN)

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LAN

• LANs consist of the following components:

– Computers – Network interface cards – Peripheral devices – Networking media – Network devices

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LAN

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LAN

• smaller scope– Building or small campus

• usually owned by same organization as attached devices

• data rates much higher• switched LANs, eg Ethernet• wireless LANs

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LAN

• LANs make it possible for businesses that use computer technology to locally share files and printers efficiently, and make internal communications possible.

• A good example of this technology is e-mail.

• They tie data, local communications, and computing equipment together.

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LAN

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LAN

• Some common LAN technologies are: – Ethernet – Token Ring – FDDI

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MAN• Metropolitan Area Network

• 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.

• For example, a bank with multiple branches may utilize a MAN.

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MAN

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MAN

• middle ground between LAN and WAN• private or public network• high speed• large area• Typically, a service provider is used to connect

two or more LAN sites using private communication lines or optical services.

• A MAN can also be created using wireless bridge technology by beaming signals across public areas.

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WAN: Internet Architecture

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WAN

• span a large geographical area• rely in part on common carrier circuits• alternative technologies used include:

– circuit switching– packet switching– frame relay– Asynchronous Transfer Mode (ATM)

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WAN

• WANs are designed to do the following: – Operate over a large geographically separated

areas – Allow users to have real-time communication

capabilities with other users – Provide full-time remote resources connected to

local services – Provide e-mail, World Wide Web, file transfer, and e-

commerce services

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WAN

• Some common WAN technologies are: – Modems – Integrated Services Digital Network (ISDN) – Digital Subscriber Line (DSL) – Frame Relay – US (T) and Europe (E) Carrier Series – T1, E1, T3,

E3 – Synchronous Optical Network (SONET)

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WAN: Internet Architecture

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Storage Area Network• 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.

• SAN technology allows high-speed server-to-storage, storage-to-storage, or server-to-server connectivity.

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Storage Area Network

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Storage Area Network• This method uses a separate network infrastructure that relieves

any problems associated with existing network connectivity.

• SANs offer the following features:

– Performance – SANs enable concurrent access of disk or tape arrays by two or more servers at high speeds, providing enhanced system performance.

– Availability – SANs have disaster tolerance built in, because data can be mirrored using a SAN up to 10 kilometers (km) or 6.2 miles away.

– Scalability – Like a LAN/WAN, it can use a variety of technologies. This allows easy relocation of backup data, operations, file migration, and data replication between systems.

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Virtual Private Network (VPN)

• A VPN is a private network that is constructed within a public network infrastructure such as the global Internet.

• Using VPN, a telecommuter can access the network of the company headquarters through the Internet by building a secure tunnel between the telecommuter’s PC and a VPN router in the headquarters.

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Virtual Private Network (VPN)

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Virtual Private Network (VPN)

Benefits of VPN:• 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.

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Intranet

• One common configuration of a LAN is an Intranet.• Intranet Web servers differ from public Web servers in

that the public must have the proper permissions and passwords to access the Intranet of an organization.

• Intranets are designed to permit access by users who have access privileges to the internal LAN of the organization.

• Within an Intranet, Web servers are installed in the network.

• Browser technology is used as the common front end to access information such as financial data or graphical, text-based data stored on those servers.

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Intranet & Extranet

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Extranet

• Extranets refer to applications and services that are Intranet based, and use extended, secure access to external users or enterprises.

• This access is usually accomplished through passwords, user IDs, and other application-level security.

• Therefore, an Extranet is the extension of two or more Intranet strategies with a secure interaction between participant enterprises and their respective intranets.

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Bandwidth

Bandwidth has been defined as the amount of information that can flow through a network in a given time.

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Bandwidth

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Question...???