Simple Defination of Networking

Networking is process to connect one computer to many computer and share the information between these computer which is connected to each other.

Networking Device List :-

• Router
• Bridge
• Switch
• Hub
• Repeater
• Multilayer Switch
• Protocol Converter
• Bridge Router(Brouter)
• Digital media receiver
• Proxy
• Firewall
• network Address Translator
• Multiplexer
• Network Card
• modem
• ISDN terminal adapter
• line Driver

Router

Router is a networking device. Its use to connect two different network.We can share the information of two different sites with help of router.
There are many companies who makes the router.But mostly companies are use Cisco Routers only.
There are many series of router in the market.

• Cisco 800 Series Routers
• Cisco 1600 Series Routers
• Cisco 1700 Series Routers
• Cisco 2500 Series Routers
• Cisco 2600 Series Routers
• Cisco 3600 Series Routers
• Cisco 3700 Series Routers
• Cisco 6400 Series Routers
• Cisco 7200 Series Routers
• Cisco 7300 Series Routers
• Cisco 7400 Series Routers
• Cisco 7500 Series Routers
• Cisco 7600 Series Routers
• Cisco 10000 Series Routers
• Cisco 12000 Series Routers

Bridge

bridge is a product that connects a local area network (LAN) to another local area network that uses the same protocol (for example, Ethernet or Token Ring).

Switch

A network switch is a small hardware device that joins multiple computers together within one local area network (LAN). Technically, network switches operate at layer two (Data Link Layer) of the OSI model.

Hub

Hub is commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

Repeater

a repeater is a device that receives a digital signal on an electromagnetic or optical transmission medium and regenerates the signal along the next leg of the medium. In electromagnetic media, repeaters overcome the attenuation caused by free-space electromagnetic-field divergence or cable loss. A series of repeaters make possible the extension of a signal over a distance.

Multilayer Switch

A multilayer switch (MLS) is a computer networking device that switches on OSI layer 2 like an ordinary network switch and provides extra functions on higher OSI layers.

Protocol Converter

A Protocol Converter is a device used to convert standard or proprietary protocol of one device to the protocol suitable for the other device or tools to achieve the interoperability.

Bridge Router(Brouter)

A network device that combines the functions of a bridge and a router in one unit. It may support multiple protocols by routing routable packets and bridging non-routable packets. Or, it may support a variety of bridging requirements while providing routing.

Digital media receiver

A digital media receiver (DMR), also commonly referred to as a media extender, media streamer, or digital media adapter (DMA), is a home entertainment device that can connect to a home network to retrieve digital media files (such as music, pictures, or video) from a personal computer or other networked media server and play them back on a home theater system or TV. The DLNA organization refers to these devices as digital media renderers (DMR).

Proxy

A proxy is a web page that provides Internet users with the ability to browse web sites that may be blocked by a content filter, such as WebSense or SmartFilter. By making use of the proxy as the portal to the blocked site, it is possible to circumvent the work of whatever content filter is in place. At the same time, the proxy site also helps to mask the visit to the site, so that there is less evidence that the content filter was not successful in preventing the visit.

Firewall

A firewall is a part of a computer system or network that is designed to block unauthorized access while permitting authorized communications. It is a device or set of devices that is configured to permit or deny network transmissions based upon a set of rules and other criteria. Firewalls are thus a specialized type of router focusing on specific types of network security functions.

Figure 1-1. The two major classes of firewall design

Network Address Translator

network address translation (NAT) is the process of modifying network address information in datagram (IP) packet headers while in transit across a traffic routing device for the purpose of remapping one IP address space into another.

Figure 1-2. Example of network address translation

Multiplexer

a multiplexer or mux is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n select lines, which are used to select which input line to send to the output.

Figure 1-3. Function of Multiplexer.

Network Card

A network card is an expansion card which installs into a computer and enables that computer to physically connect to a local area network.

Figure 1-4. Network Card

Modem

A modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used over any means of transmitting analog signals, from driven diodes to radio.

ISDN Terminal Adapter

A terminal adapter (TA) is a hardware interface between a computer and an Integrated Services Digital Network line. It’s what replaces a modem when you are using an ISDN connection. Unlike “plain old telephone service,” which carries signal in analog (voice) form between your computer and the telephone company’s office, ISDN carries signals in digital form so there is no need to modulate and demodulate between analog and digital signals. The terminal adapter is what you have to install on a computer so that data can be fed directly into the ISDN line in digital form. Since ISDN service is not available from telephone companies in all areas, the terminal adapter is not usually built into a computer. You purchase and install it when you sign up for ISDN service.

Line Driver

In electronics, a line driver is an amplifier used to improve the strength of an analog or digital signal at its source by driving the input to the transmission line with a higher than normal signal level. This increases the quality of a transmission over a long run of cable. An example of a line driver is an amplifier used to extend the range of an RS-232C digital signal beyond 15 m (50ft) while maintaining a specified bit error ratio. In mobile audio, use of a line driver allows an amplifier’s gain to be set lower, reducing low-level noise. Line drivers may also be used to enhance distortion in guitar amplifiers.

What is SQL Server

SQL Server is a relational database management system (RDBMS) from Microsoft that’s designed for the enterprise environment. SQL Server runs on T-SQL (Transact -SQL), a set of programming extensions from Sybase and Microsoft that add several features to standard SQL,

including transaction control, exception and error handling, row processing, and declared variables.

Code named Yukon in development, SQL Server 2005 was released in November 2005. The 2005 product is said to provide enhanced flexibility, scalability, reliability, and security to database applications, and to make them easier to create and deploy, thus reducing the complexity and tedium involved in database management. SQL Server 2005 also includes more administrative support.

The original SQL Server code was developed by Sybase; in the late 1980s, Microsoft, Sybase and Ashton-Tate collaborated to produce the first version of the product, SQL Server 4.2 for OS/2. Subsequently, both Sybase and Microsoft offered SQL Server products. Sybase has since renamed their product Adaptive Server Enterprise.

What can Sql Do.

• SQL can execute queries against a database
• SQL can retrieve data from a database
• SQL can insert records in a database
• SQL can update records in a database
• SQL can delete records from a database
• SQL can create new databases
• SQL can create new tables in a database
• SQL can create stored procedures in a database
• SQL can create views in a database
• SQL can set permissions on tables, procedures, and views

Sql Select Statement

The select command is the most important for most users. Its purpose is to retrieve data.

select * from table_name
or
select columnlist
from tablelist

Sql Distinct Statement

The SQL DISTINCT command used along with the SELECT keyword retrieves only unique data entries depending on the column list you have specified after it.

select distinct columnlist


from tablelist

Sql where Clause

The WHERE clause is used to extract only those records that fulfill a specified criterion.

select * from table_name

where column_name

or

select * from tablelist

where columnlist

Sql And & OR Operators

The AND operator displays a record if both the first condition and the second condition is true.

SELECT * FROM table_name

WHERE column_name

OR column_name

The OR operator displays a record if either the first condition or the second condition is true.

SELECT * FROM table_name

WHERE column_name

OR column_name

Combine use of AND & OR Operators

You can also combine AND and OR (use parenthesis to form complex expressions).


SELECT * FROM Persons WHERE

column_name

AND (column_name OR column_name)

Sql ORDER BY Keyword

The ORDER BY keyword is used to sort the result-set.


The ORDER BY keyword is used to sort the result-set by a specified column.

The ORDER BY keyword sort the records in ascending order by default.

If you want to sort the records in a descending order, you can use the DESC keyword.

SELECT column_name(s)


FROM table_name

ORDER BY column_name(s) ASC
DESC

Sql INSERT INTO Statement

The INSERT INTO statement is used to insert new records in a table.


There is two form of INSERT INTO statement.

The first form doesn’t specify the column names where the data will be inserted, only their values:-

INSERT INTO table_name

Values (Value 1,Value 2,Value 3,…..)

The second form specifies both the column names and the values to be inserted:-

INSERT INTO table_name

(column1, column2, column3,…)

Values (Value 1,Value 2,Value 3,…..)

Sql UPDATE statement

The UPDATE statement is used to update records in a table.


UPDATE table_name

SET column1=value, column2=value2,…

WHERE some_column=some_value

Sql DELETE Statement

The DELETE statement is used to delete records in a table.


DELETE FROM table_name

WHERE some_column=some_value

Sql ALL Commands

SQL Statement	Syntax
AND / OR	SELECT column_name(s)
	FROM table_name
	WHERE condition
	AND|OR condition
ALTER TABLE	ALTER TABLE table_name
	ADD column_name datatype
	or
	ALTER TABLE table_name
	DROP COLUMN column_name
AS (alias)	SELECT column_name AS column_alias
	FROM table_name
	or
	SELECT column_name
	FROM table_name AS table_alias
BETWEEN	SELECT column_name(s)
	FROM table_name
	WHERE column_name
	BETWEEN value1 AND value2
CREATE DATABASE	CREATE DATABASE database_name
CREATE TABLE	CREATE TABLE table_name
	(
	column_name1 data_type,
	column_name2 data_type,
	column_name2 data_type,
	...
	)
CREATE INDEX	CREATE INDEX index_name
	ON table_name (column_name)
	or
	CREATE UNIQUE INDEX index_name
	ON table_name (column_name)
CREATE VIEW	CREATE VIEW view_name AS
	SELECT column_name(s)
	FROM table_name
	WHERE condition
DELETE	DELETE FROM table_name
	WHERE some_column=some_value
	or
	DELETE FROM table_name
	(Note: Deletes the entire table!!)
	DELETE * FROM table_name
	(Note: Deletes the entire table!!)
DROP DATABASE	DROP DATABASE database_name
DROP INDEX	DROP INDEX table_name.index_name (SQL Server)
	DROP INDEX index_name ON table_name (MS Access)
	DROP INDEX index_name (DB2/Oracle)
	ALTER TABLE table_name
	DROP INDEX index_name (MySQL)
DROP TABLE	DROP TABLE table_name
GROUP BY	SELECT column_name, aggregate_function(column_name)
	FROM table_name
	WHERE column_name operator value
	GROUP BY column_name
HAVING	SELECT column_name, aggregate_function(column_name)
	FROM table_name
	WHERE column_name operator value
	GROUP BY column_name
	HAVING aggregate_function(column_name) operator value
IN	SELECT column_name(s)
	FROM table_name
	WHERE column_name
	IN (value1,value2,..)
INSERT INTO	INSERT INTO table_name
	VALUES (value1, value2, value3,....)
	or
	INSERT INTO table_name
	(column1, column2, column3,...)
	VALUES (value1, value2, value3,....)
INNER JOIN	SELECT column_name(s)
	FROM table_name1
	INNER JOIN table_name2
	ON table_name1.column_name=table_name2.column_name
LEFT JOIN	SELECT column_name(s)
	FROM table_name1
	LEFT JOIN table_name2
	ON table_name1.column_name=table_name2.column_name
RIGHT JOIN	SELECT column_name(s)
	FROM table_name1
	RIGHT JOIN table_name2
	ON table_name1.column_name=table_name2.column_name
FULL JOIN	SELECT column_name(s)
	FROM table_name1
	FULL JOIN table_name2
	ON table_name1.column_name=table_name2.column_name
LIKE	SELECT column_name(s)
	FROM table_name
	WHERE column_name LIKE pattern
ORDER BY	SELECT column_name(s)
	FROM table_name
	ORDER BY column_name [ASC|DESC]
SELECT	SELECT column_name(s)
	FROM table_name
SELECT *	SELECT *
	FROM table_name
SELECT DISTINCT	SELECT DISTINCT column_name(s)
	FROM table_name
SELECT INTO	SELECT *
	INTO new_table_name [IN externaldatabase]
	FROM old_table_name
	or
	SELECT column_name(s)
	INTO new_table_name [IN externaldatabase]
	FROM old_table_name
SELECT TOP	SELECT TOP number|percent column_name(s)
	FROM table_name
TRUNCATE TABLE	TRUNCATE TABLE table_name
UNION	SELECT column_name(s) FROM table_name1
	UNION
	SELECT column_name(s) FROM table_name2
UNION ALL	SELECT column_name(s) FROM table_name1
	UNION ALL
	SELECT column_name(s) FROM table_name2
UPDATE	UPDATE table_name
	SET column1=value, column2=value,...
	WHERE some_column=some_value
WHERE	SELECT column_name(s)
	FROM table_name
	WHERE column_name operator value