Intranet and LAN

Objectives :• Basic of Intranet• Intranet Setup• Feature of LAN• Hardware requirement of LAN• Topology in LAN

What is Intranet ?Smaller private version of Internet. It uses Internet protocols to create enterprise-wide network which may consists of interconnected LANs.

It may or may not include connection to Internet.

Intranet is an internal information system based on Internet technology and web protocols for implementation within a corporate organization.

This implementation is performed in such a way as to transparently deliver the immense informational resources of an organization to each individual’s desktop with minimal cost, time and effort.The Intranet defines your organization and display it for everyone to see.If everyone knowswhat the company stands for,what the company’s strategic vision is,what the guiding company principles are,who the clients and partners are,then they can focus more clearly on what their own contributions are to the organization.

Who needs an Intranet :

In an Intranet environment is used to communicate over two or more networks across different locations.

1. Users having multi-locations with multi-networks.2. Users having single locations with multi-networks.3. Users having single locations with single networks.

•What’s really HOT about Intranets :

From a technology point of view, an Intranet is simply beautiful. because :

1. It is scale able.2. It is Interchangeable.3. It is platform independent.4. It is Hardware independent.5. It is vendor independent.6. It is open.

Why Intranet for an Organization:

1.A Decision Making Tool2.A Complete Communication Tool3.A 21st Century Telephone.4.An ISO Tool5.A Target Marketing Tool

Applications of Intranet :

1.Publishing Corporate documents2.Access into searchable directories3.Excellent Mailing Facilities4.Proper Sharing of Information5.Developing Groupware Applications

A Typical Intranet setup

Technical Overview of the Intranet Technology :

Intranet runs on open TCP/IP network, enable companies to employ the same type of servers and browser used for World Wide Web for internal applications distributed over the corporate LAN .A typical Intranet implementation involves a high end machine called a server which can be accessed by individual PCs commonly referred to as clients, through the network.The Intranet site setup can be quite inexpensive, especially if your users are already connected by LAN. Most popular Intranet web servers can run on a platform widely found in most organizations.

Intranet In CirclesAs per CMD’s instructions every circle has to implement an integrated customer services package and a call centre in each circle. The setting up of an intranet in a circle is a must to achieve this. The Intranet will be utilised for the following applications•Implementation of an integrated package.•Implementation of centralized FRS with IVRS•Connecting SSAs to the call centre.•Establishment of an intranet server at circle office and SSAs accessing it.•Implementation of IUC billing project that is coming up. Every POI (almost all SDCCs) to have PCs to collect the CDRs and then to transport the CDRs to a central server at Level I TAX.•Implementation of PGRAMS and MIS projects.Implementation of any web based software projects such as Store/Inventory Management.

Intranet applications in a circle :

Every circle should have an intranet server. Just like we have an intranet portal under bsnl.co.in, every circle must have an intranet server which should have the following All posting/transfer/relieving orders issued within circle to be hosted on the intranet.All letters circulars/letters issued from different sections of the circle office to be hosted on the server for immediate access by SSAs. Each section in circle office –Admn., Operations, Marketing, Finance, Planning, Computers etc can have web pages hosted on the server.A database can be maintained for MIS reports and all other reports to be sent periodically by SSAs to circle office. The database can have front end forms designed in ASP or PHP for the SSAs to input the data. Separate programs can be developed to consolidate the data fed by SSAs.All data prepared and /or distributed during SSA Heads meetings can be hosted on the Intranet.The implementation of the above will reduce the usage of paper and also reduce the usage of FAX.

8 port Ethernet

switch

Layer 3 switch 48 port RJ45

PCsTo Other SSAs

To Transmission Network

G.703 Converter

At 2 Mbps

With Ethernet

port

Network at Computer Center at Circle Headquarters

Servers

In Cluster

8 port Ethernet switch

Layer 3 switch 24 port RJ45

PCs

To Transmission Network

G.703 ConverterAt 64 KbpsWith EthernetPort (500m.)

Network at SSA HQs.

G.703 Converter

TransmissionRoom

8 port Ethernet switch

PCs

64Kbps<5 km.

To LAN at Exges.

To SDCCs

LOCAL AREA NETWORK

LAN Concepts and ComponentsFeatures of LAN

•Sharing of files, directories, data and program from other computers/File Server.•Sharing of Hard Disk area.•Sharing of Printers, using a separate print server PC. The File Server PC also can do this job.•Sharing of CD Drives, using special driver software.•Sharing Fax Machines, using the relevant driver software.•Sharing the Modem is also possible.•Sharing, as above, from a remote terminal, with the help of modem, telecom line etc. is also possible.

Hardware required for LAN1.In the LAN, we have the following hardware items: 2.A Central PC (preferably 486 and above) 3.Hard Disk 4.Networking Operating System 5.Other data and applications as needed6.The central PC is linked to other Computers by means of cables/wires7.Network Interface Cards (NICs)8.Printer may be connected to a PC which is exclusively marked as Printer Server9.The printer may also be connected to the Central PC — File Server

File Server : Pentium, Mono monitor, 32/64/128MB, 20/40 GB HARD DISK, 1.44MB FLOPPY DISK

Work Station : 586 with Color monitor, 32/64MB, HARD DISK and FLOPPY DISK (if required)

Cable : Coaxial cable, STP (Shielded Twisted Pairs) UTP (unshielded Twisted Pair), or OFC (costly)

Interface Cards : ARCNet card, Ethernet Card, Token Ring Adopter Card.(very costly)

File Server :

File Server stores all the files needed in the networkRetrieving and Serving them

Workstations :

The connected computers (with or without HARD DISK)Nodes, Workstations have Network Interface cards (NIC)Cables are used to link them to the File Server PCCoaxial cable, Ordinary Twisted pair, UTP and OFCClient-Server Network LANPeer-to Peer LAN (Peer means equals)

Hardware :

A Simple list of the hardware specification is :

LAN Software :

1.The Novel Server needs DOS, as the local operating system, and to maintain the communication between itself and the various Network computers, printers, modem etc., it requires a special operating system called “N.O.S.” (Network Operating System)2.This NOS makes the flow of messages between the File Server and WorkStation in orderly, smooth and effective manner3.It let workstation share the HARD DISK of File Server as network drive (F:) of workstation4.The LAN printer in a different room is made to appear as a local printer of the workstation by the NOS.

The NOS has three different aspects

1.Maintaining the connectivity in the LAN among various PCs, Printers, Faxes etc.2.Responding to the various requests from the nodes, as REDIRECTED to the File Server.3.Managing the File Server DOS and to interact with it

Topology :

Topology refers to the physical data path that traffic takes across the network.Common LAN topologies are Bus, Ring and Star, Network requirements of these topologies are -

•Flexible to accommodate•Changes in physical location of the stations•Increase in number of stations.•Increase in LAN coverage.•Consistent with the media access method•Minimum cost of physical media.

Bus Topology

In bus topology, a single transmission medium interconnects all the stationsAll stations share this medium for transmission to any other stationsEvery stations listens to all the transmissions on the busEvery transmission has source and destination address so that stations can pick the messages meant for them and identify their senders.Some of the advantages of bus topology are as under:Stations are connected to the bus using a passive tap.Least amount of media is used.Coverage can be increased by extending the bus using repeaters.New stations are easily added by tapping working bus.

Star topology :

•It is in the form of a star•Each node is connected to a common hub or concentrator device, but not directly to each other•Each interconnection supports two way communication•The central controller acts as a switch to route the frames from source to the destination unlike ring or bus topologies where communication is in broadcast mode.•Wiring costs tend to be higher for the star networks than for other configurations, because each node requires its own cable.•While star topology is well understood and is based on prove technology (telephone network), its disadvantages are•Single point of failure.•No sharing of transmission

Ring Topology :

1.The cabling runs from workstation to workstation (and to the File Server) in the form of a closed loop or circle2.Messages move in one direction around the system3.When a message arrives at a node, the node examines the address information in the message4.If the address matches the node address, the message is accepted otherwise, the node regenerates the signal and places the message back on the network for the next node in the system5.The regeneration process allows a ring network to cover greater distances than Star / Bus networks. 6.It uses token-passing protocol to regulate network traffic.

Network Architectures (Media Access) :

Network architecture is a method that governs how multiple devices are allowed to share the same cableMost People identify network by its architectures.

The network architectures that you choose determines:

1. transmission speed2.cost3.cable compatibility

Architecture Xmission Speed Mbps

Compatible Cable

Topology

Ethernet 10 Coaxial, UTP Star, busToken Ring 4 or 16 UTP, STP Star, ringARCnet 2.5 Coaxial, UTP Star, busFDDI 100 Fiber optic Star, ringCDDI 100 UTP, STP Star, ringATM 150-622 UTP,STP, Fiber Star100VG-AnyLAN

100 UTP, STP Star

100BaseX 100 UTP Star

Comparing Network Architectures

Ethernet :

It is the oldest Surviving network typeEthernet follows CSMA/CD Protocol for Transmission(Carrier Sense Multiple Access / Collision Detection)

Advantages :

•Inexpensive adapter cards•Easy installation•Various types of cables can be used•Widely used•Speed (up to 10 Mbps)

Disadvantages :

•Poor performance under heavy loads (CSMA/CD, the Data access scheme used by Ethernet does not hold up well under heavy use)•Difficult to troubleshoot (in the bus configuration, a failure at one point can cause the entire network to go down)

Ethernet's CSMA/CD Protocol – Transmission :

•A node must first listen to the network cabling before it is permitted to transmit anything over the network•If it does not detect a carrier on the cable, the station transmits the frame•A carrier is an electronic signal that indicates that another device is already using the cable)•When the cable is in use, the node waits a set amount of time before trying to transmit again•After the frame is transmitted, the node continues to listen to the cable for any possible collisions•A collision occurs when another node on the network transmits a frame while the cable is in use•If a collision occurs, the frames are corrupted•Before the frames can be retransmitted, each node involved in the collision must back off and wait a random amount of time

Ethernet's CSMA/CD Protocol – Reception :

1.Each node must examine all the frames that pass by.2.When the packet is not intended for the node viewing it, the packet is passed on to the next station. 3.If the node receives a packet for which it is the recipient, the node confirms the integrity of the packet before the node processes it.4.Frame should not be longer than 1,518 bytes and lesser than 64 bytes.5.Frames should pass Cyclic Redundancy Check (CRC).