What is IP Address and Subnet Masks?

IP Address is the set of numbers which uniquely identifies the machine on a network and the network to which it is attached. IP Address identifies the machine's connection to the network but not the machine itself. When a machine's location on the network changes,the IP address also changes. TCP/IP uses this 32 bit IP Address to identify a machine on a network and the network to which it is attached.

The machine on a network is called as Host. Each TCP/IP host is identified by a unique IP Address. Internally each IP Address is separated into two parts network ID and a Host ID.

The network ID identifies a single network segment within the larger internetwork. Internetwork is a network of networks. All machines that are access to the same network have a common network ID. The host ID identifies a TCP/IP node within each network. A node may be a workstation or server or router or other TCP/IP device.

IP Addresses are four sets of 8 bits,totally 32 bits. IP Addresses are usually expressed in decimal notation instead of long binary strings. These 8 bit octets are converted to decimal numbers and separated by periods. For example 192.168.1.2 is an IP Address.

There are 5 IP Address classes. Out of these 5 three classes are used for assignment to TCP/IP nodes. They are Class A,B and C.

The IP Address class defines which bits are used for network ID and host ID parts of each address. It also defines howmany networks and hosts per network can be supported.

For example p.q.r.s represent the four octet values in any IP Address.

For Class A the value of p is 1-126. First octet p represents network ID. The remaining 3 octets q.r.s represents Host ID. Class A supports 126 networks and 16,777,214 hosts per network.

For Class B the value of p is 128-191. First two octets p.q represents network ID. The last two octets r.s represents Host ID. Class B supports 16,384 networks and 65,534 hosts per network.

For Class C the value of p is 192-223. First three octets p.q.r represents network ID. The last octet s represents Host ID. Class C supports 20,97,152 networks and 254 hosts per network.

Subnet Masks:

Subnet Mask is also a 32 bit number. Subnet Mask identifies Network ID and Host ID parts within the IP Address. Subnet Mask uses bit groups of all ones to identify the network ID and uses bit groups of all zeroes to identify the Host ID parts of an IP Address.

For example take IP Address 192.168.1.2 The value of first octet is 192. So this is Class C IP Address. p.q.r represents network ID and s represents Host ID. So for above IP address network ID is 192.168.1 and Host ID is 2.

For the above IP Address Subnet Mask number is 11111111 11111111 11111111 00000000 In decimal notation it is 255.255.255.0

For Class A IP Address Subnet mask is 255.0.0.0
For Class B IP Address Subnet mask is 255.255.0.0

Note: Articles on Windows NT,Windows 2000 Server,Windows 2003 Server will come soon on my blog under the same NETWORKING section.

What is TCP/IP Protocol?

Protocol is a pre defined set of rules. When nations conduct business between them then they follow certain rules so that everything proceeds smoothly. Similarly if one computer is communicating with another one then they both must follow a pre defined set of rules called protocol. If they follow the protocol properly then only message will be transferred from one machine to other,regardless of what type of machines they are and what operating systems they run. Communications are possible with the help of a software that can manage the protocol. That software is nothing but TCP/IP.

TCP/IP is a software based communications protocol that provides network services such as remote logins,remote file transfers, and electronic mail. It transfers information from one machine to another. It provides reliable transfer of data. TCP/IP handle errors in transmission.manage the routing of data,manage the delivery of data and control the transmission by the use of predetermined status signals. TCP/IP was designed with layers. TCP/IP responsible for assembling data passed from higher layer applications into standard packets and ensuring that the data is transferred correctly.

TCP/IP is a combination of two protocols transmission control protocol and Internet protocol. Internet protocol is responsible for moving the packets of data assembled by TCP across networks. It uses a set of unique addresses(IP Addresses)for every device on the network to determine routing and destinations. Internet protocol main tasks are addressing of datagrams of information between computers and managing the fragmentation process of these datagrams. The protocol has a formal definition of the layout of a datagram of information and the information of a header composed of information about the datagram. IP is responsible for the routing of a datagram and determines where it will be sent .

IP does not guarantee datagram's delivery. It has no reliability. It simply handles the routing of datagrams. If problem occurs IP discards the packet and generate an ICMP error message to the sender. But TCP takes the charge if problems occur. TCP provides reliable transfer of data. TCP is responsible for ensuring the transfer of a datagram from the source to the destination machine and receive acknowledge receipt of the datagram from the destination machine.

Note: Articles on Windows NT,Windows 2000 Server,Windows 2003 Server will come soon on my blog under the same NETWORKING section.

What is a Wide Area Network?

Introduction:

A set of computers and peripherals connected together by a medium is called a network. All these devices on the netwok communicate with each other through a protocol. All these devices on a netwok can be in the same room or scattered through a building or scattered in different buildings or different cities. All these devices can be separated by many miles by the use of dedicated telephone lines or microwave etc.

Peripherals are nothing but Printers,Scanners,Modems,Plotters etc.
Protocol is a predefined set of rules.

Wide area network:

If these devices on a network are scattered in different buildings,or different cities and these devices setup into several LAN's that are joined together into a larger structure called a Wide area network(WAN).

A Wan is composed of two or more Lan's. All these Lan's joined by a telephone line or dedicated cable. One or more machines act as the link between each Lan and Wan. These linking machines are called gateways. Depending on tasks perfomed by these linking machines,they are also called as Router and Bridge.

We all know Internet is not a single network. Internet is a collection of networks that communicate with each other through gateways.Gateways act as a relay between networks. It passes data from network to network searching for a destination address. Networks talk to each other through gateways. Gateways perform protocol translation from one network to another.

Bridge connects two or more networks that use the same protocol.

Router forwards datagrams around the network.

Note: Articles on Windows NT,Windows 2000 Server,Windows 2003 Server will come soon on my blog under the same NETWORKING section.

What is a Local Area Network?

Introduction:

A set of computers and peripherals connected together by a medium is called a network. All these devices on the netwok communicate with each other through a protocol. All these devices on a netwok can be in the same room or scattered through a building or scattered in different buildings or different cities. All these devices can be separated by many miles by the use of dedicated telephone lines or microwave etc.

Peripherals are nothing but Printers,Scanners,Modems,Plotters etc.
Protocol is a predefined set of rules.

Local Area Network:

If the devices on a network are located in a single place such as a building or a group of rooms,they are called a local area network. Usually all these devices on the network are connected by a single type of network cable in Lan's.

LAN Topologies:

The main dominant Lan topologies are Bus,Hub(Star) and ring.

Bus Topology:

Bus network consists of a single linear cable called a Bus(or Backbone). Each device is attached to this backbone through a junction box or transceiver. From each transceiver another short cable runs to the device's netwok adapter. Signal bounce is eliminated by a terminator at each end of the bus. Barrel connectors can be used to lengthen the cable. For regenerating signals Repeaters are used.Each device has a special address. Data is sent to all devices on the backbone. Each device examines every packet and accepts only messages addressed to them.

Main advantage of bus network is that it allows for a high speed bus. But performance degrades when more devices are added to the bus. Bus topology is good for small network. The entire network goes down if the backbone goes down.

Hub Topology:

This network uses a main cable called the backplane. From the backplane set of cables goes to hubs. All devices are connected to the ports of these hubs. We can set up small hub network with standard Ethernet cables. Also we can set up large hub network by using a high speed fibre optic backplane.The hub networks are easy to set up and maintain.

In this network all devices are connected by cable segments to a centralized hub. Signal travels through the hub to all the computers. The network functions normally if a computer goes down. This network requires more cable.

Ring Topology:

All the devices are connected on a single circle of cable. No termination required as in Bus topology. For regenerating signals no repeaters are used. The computers act as repeaters. The Ring networks are easy to set up and maintain.

Note: Articles on Windows NT,Windows 2000 Server,Windows 2003 Server will come soon on my blog under the same NETWORKING section.

How to make stock charts open in www.nseindia.com,www.bseindia.com and any other Web sites for Windows Xp users?

For any serious stock investor stock charts are very important. Before buying or selling stocks,stock investors analyze stock charts. After analyzing the charts they will take decision whether to buy,sell or not. So stock charts are one of the key points at the time of buying or selling stocks.

Unfortunately for Windows Xp users stock charts are not opening from nseindia.com,bseindia.com and some other sites. By default Win Xp is bundled with internet Explore 6.0. Unfortunately Sun Micro systems withdrawn support of J2SE Runtime Environment(JRE) to Win Xp. So java applications like stock charts are not opening for windows Xp users.

We have to download that software JRE 5.0 Update 9 for running stock charts. Go to http://java.sun.com site. On the main page you will find Downloads tab. Click downloads. Under Java technology click java SE. In this window you will find Java Run time environment(JRE) 5.0 Update 9. By the side of it you will find Download button. Just click it. In this window click the radio button “Accept license agreement”. Below this button you will find Windows Platform - J2SE Runtime Environment 5.0 Update 9. Below this you will find two files. You can download any one of the two files.

First file will download complete(JRE) 5.0 Update 9 software. After downloading this file you can install it.

Where as second file downloads only application file(245.76 kb). First download it. Then double click that file and install JRE from net. So while installing your computer must be connected to internet.

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