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Internet service provider
An Internet service provider (abbr. ISP, also called Internet access provider or IAP) is a business or organization that provides to consumers access to the Internet and related services. In the past, most ISPs were run by the phone companies. Now, ISPs can be started by just about any individual or group with sufficient money and expertise. In addition to Internet access via various technologies such as dial-up and DSL, they may provide a combination of services including Internet transit, domain name registration and hosting, web hosting, and colocation.
ISP connection options
ISPs employ a range of technologies to enable consumers to connect to their network. For "home users", the most popular options include dial-up, DSL (typically ADSL), Broadband wireless access, Cable modem, and ISDN (typically BRI). For customers who have more demanding requirements, such as medium-to-large businesses, or other ISPs, DSL (often SHDSL or ADSL), Ethernet, Metro Ethernet, Gigabit Ethernet, Frame Relay, ISDN (BRI or PRI), ATM, satellite Internet access and SONET are more likely. With the increasing popularity of downloading music and online video and the general demand for faster page loads, higher bandwidth connections are becoming more popular.
 How ISPs connect to the Internet
Just as their customers pay them for Internet access, ISPs themselves pay upstream ISPs for Internet access. In the simplest case, a single connection is established to an upstream ISP using one of the technologies described above, and the ISP uses this connection to send or receive any data to or from parts of the Internet beyond its own network; in turn, the upstream ISP uses its own upstream connection, or connections to its other customers (usually other ISPs) to allow the data to travel from source to destination.
In reality, the situation is often more complicated. For example, ISPs with more than one Point of Presence (PoP) may have separate connections to an upstream ISP at multiple PoPs, or they may be customers of multiple upstream ISPs and have connections to each one at one or more of their PoPs. ISPs may engage in peering, where multiple ISPs interconnect with one another at a peering point or Internet exchange point (IX), allowing the routing of data between their networks, without charging one another for that data - data that would otherwise have passed through their upstream ISPs, incurring charges from the upstream ISP. ISPs who require no upstream, and have only customers and/or peers, are called Tier 1 ISPs, indicating their status as ISPs at the top of the Internet hierarchy. Routers, switches, Internet routing protocols, and the expertise of network administrators all have a role to play in ensuring that data follows the best available route and that ISPs can "see" one another on the Internet.
Virtual ISP
A Virtual ISP (vISP) purchases services from another ISP (sometimes called a wholesale ISP or similar within this context) that allow the vISP's customers to access the Internet via one or more Points of Presence (PoPs) that are owned and operated by the wholesale ISP. There are various models for the delivery of this type of service, for example, the wholesale ISP could provide network access to end users via its dial-up modem PoPs or DSLAMs installed in telephone exchanges, and route, switch, and/or tunnel the end user traffic to the vISP's network, whereupon they may route the traffic toward its destination. In another model, the vISP does not route any end user traffic, and needs only provide AAA (Authentication, Authorization and Accounting) functions, as well as any "value-add" services like email or web hosting. Any given ISP may use their own PoPs to deliver one service, and use a vISP model to deliver another service, or, use a combination to deliver a service in different areas. The service provided by a wholesale ISP in a vISP model is distinct from that of an upstream ISP, even though in some cases, they may both be one and the same company. The former provides connectivity from the end user's premises to the Internet or to the end user's ISP, the latter provides connectivity from the end user's ISP to all or parts of the rest of the Internet.
A vISP can also refer to a completely automated white label service offered to anyone at no cost or for a minimal set-up fee. The actual ISP providing the service generates revenue from the calls and may also share a percentage of that revenue with the owner of the vISP. All technical aspects are dealt with leaving the owner of vISP with the task of promoting the service. This sort of service is however declining due to the popularity of unmetered internet access also known as flatrate.
What is an ISP?
An ISP (Internet Service Provider) is a company that collects a monthly or yearly fee in exchange for providing the subscriber with Internet access.
An ISP might provide dial-up service, cable, DSL, or other types of Internet access. Some ISPs are local while others are national. A national ISP will provide access throughout most of the nation, while a local ISP will only serve subscribers in a limited geographical region.
When looking for an ISP the initial consideration is the type of access desired. Some ISPs only offer dial-up access which is the slowest type of connection. If you want cable service, you'll be checking with your local cable TV provider to see if cable access is offered. For DSL service, you may have multiple choices - or it could be that DSL is not yet available in your area. Often this can be remedied with a call to the phone company to upgrade local telephone lines.
Every ISP has a privacy policy and Terms of Service (TOS) contract that subscribers must agree to before subscription will be accepted. The privacy policy will state what the company will and will not do with personal information collected at the time of sign-up. Name, address, and normally a credit card number are required. The privacy policy should also state under what conditions your personal information might be shared with third parties, government officials, or others. The TOS contract stipulates how you can use the service. For example, dial-up access is often sold as "unlimited access" but this is not to be taken literally. Dial-up accounts normally limit hours per month to 250-400, depending on the ISP. Truly unlimited access (leaving your computer on and actively connected to the Internet 24/7) is called dedicated access. Most DSL or cable subscriptions allow dedicated access.
The Terms of Service contract of the ISP will also state rules about hacking, protecting copyrighted materials, denial of service attacks, harassing other people, spam, compromising the service, and many other issues. These are as much for the legal protection of the ISP as to let potential subscribers know what the ISP will and will not tolerate. If you are planning on using web space provided by the ISP, check for limitations here too. Many ISPs do not allow commercial websites to be set up on their servers. This usually means that nothing can be sold from your personal webspace, including for example, a software program you wrote, original music, or any other item. ISP websites are normally for personal use only, to blog, post pictures, and so on.
Once you find an ISP that offers the services, privacy policy and TOS you can live with, you can sign up online through a public terminal, or call. From here all that needs to be done is to enter the ISP access number and a few other parameters into the networking software on your computer.
ISP services range in price according to the package offered, and type of service. Dial-up is least expensive, and perks will vary greatly between ISPs. Some offer multiple email accounts, others vast amounts of webspace, and still others discounts for paying in advance. DSL and cable companies will also differ, so carefully read through offerings before deciding. If you are getting an ISP other than cable, you will likely have choices. There are many websites that offer reviews from present subscribers of various ISPs, which might be helpful in making a decision.

 ISP Connection

ISP connections split into two main categories: Dialup ISP and Broadband Internet.
Dialup ISP

Dialup is the most basic type of ISP in which you require phone line to connect to internet. Dialup internet intended to provide 56 Kbps or lower speed. For internet connection you require a modem that connected to a computer and telephone link to ring up to your internet service provider. With dial up connection your internet surfing speed restrict to 56 Kbps but in actual you will never surf faster than 52 kbs because of FCC regulation and overhead.

Dialup connection requires only telephone line so you can connect to internet even you are in any rural areas. For connecting to internet using your dialup you need to call to your ISP Provider, this is called handshaking mode. Once connection established you can start surfing internet. The handshaking mode is a source of frustration because many dialup users dial same number than your chance of getting connection will be less or it will take to connect. Dialup connection is the cheapest solution for your internet need but your telephone line gets engaged when you are using your dialup connection. So, it will cost you higher because call duration incurs cost.

High speed dial up is little bit faster than any regular dial up connection. High speed dialup use V92 modem technology which compress the image, files and web pages. So you can access website faster than any regular dialup. But in actual with high speed dialup your internet speed will never exceed to 56Kbps.

Broadband Internet

Broadband internet is many time faster than dial up connection. Broadband internet is high data transmission internet connection and is capable of providing 256 Kbps speed.

Broadband internet mainly divides into: DSL and Cable Modem

DSL: - DSL is abbreviation of “Digital Subscriber Line”. DSL is a type of Broadband Internet with which you can start surfing from 128 Kbps. Maximum speed of 24000 Kb/s you expect from DSL.
DSL is intended to provide high speed internet connection for home users, companies, offices or organization. DSL can be divided into ADSL, HDSL and RADSL. DSL connection requires telephone line for getting internet connection. Data transfer using your telephone line without engaging your phone, means you can make call even when you are using internet.

Copper wire that used to connect your home or office to a telephone company is used to carry both data and voice signals. Telephone use analog signals to transfer voice from one phone user to another. Computer can read only binary codes so we need a modem between your telephone line and computer for demodulating analog signal into binary numbers 0 and 1.

DSL Advantages

• You can use telephone line even when you are surfing internet.
• You can have DSL connection with your old telephone wiring. You don't need new wiring for getting DSL internet.
• Your surfing experience increase significantly than regular dialup or ISDN.
• You can view high flash website, download songs or movies, play online games with DSL connection.

DSL Disadvantage

• Its not possible to have DSL internet in all areas. For having a DSL connection you need to have telephone line.
• Your surfing speed decrease if you are not leaving closer to your telephone company office.
• Price is little higher than regular dial up.
• Downloading speed is higher compare to uploading speed.
Wireless Internet
Wireless internet is a type of broadband internet in which you do not need wired connection for internet access. You can access Internet via wireless networks. Wireless internet use WAP (Wireless Application Protocol) to give you wireless internet connection. Wireless internet uses Radio Frequency signal for accessing World Wide Web or Internet. Wireless application protocol use WAP-enabled device that connect you to wireless service provider by detecting radio signals. When internet surfer requesting a web page the request is send by a Web Server to a WAP gateway. Wireless Application Protocol has WAP encoder, script compiler and protocol adapters to convert HTTP request into WML. And WAP Gateway than send sent encoded data to your wireless device.
Wireless Internet Advantages

• Wireless internet does not require any cable for internet connection.
• You are able to get internet connection when you are traveling.
• Internet surfing speed is higher than dialup connection.
Wireless Internet Disadvantages

• Wireless internet is more expensive.
• Wireless internet depends on weather for its optimum performance.
Cable Internet
Cable Internet is a kind of Broadband Internet in which Internet connection brought to you by means of cable TV line. Anyone who has cable TV connection can get Internet connection from their existing cable provider. Cable connection that used to carry television signal is capable of transmitting hundred Mega signals. Some cable use coaxial cable for transmitting signal and some other system use fiber-optic cable that come from cable provider and than distributed to different areas.
Your cable internet provider use same cable that is responsible for cable TV. Cable modem comes into role and it downstream data into 6 MHz channel. Upstream data that internet surfer sent back to internet don't use more than 2 MHz. Cable internet company require two types of equipments for transmitting signals. Fist one is cable modem that to be fixed at internet buyers place and second one is cable modem termination system in their company.
Cable Internet Advantages
• Cable internet is faster than any dialup internet connection.
• Cable internet is always on, means you can access internet whenever you want. You don't need to dial at your internet service provider for getting internet connection.
• You can use your phone even you are using internet.
• Able to surf faster and its easy to download movies, music, images, files, etc. Also with cable internet you can even play online games.
Cable Internet Disadvantages
• You can get cable internet connection only through your cable TV service provider.
• Cost of having cable internet is much higher than dialup internet connection.
• You can not use it while you are traveling.
ISDN Internet
ISDN is an abbreviation of Integrated Services Digital Network. ISDN is a transmission system that use traditional telephone network for carrying voice, data, image and signals. ISDN is easy to use digital communication system that is capable of transferring 128 Kbps which is faster than a 28.8 Kbps modem.
ISDN connection has three different services 1. Basic Rate Interface 2. Primary Rae Interface and 3. Broadband Interface. Basic Rate Interface is widely used ISDN type that most suitable for home users.
ISDN Internet Advantages
• ISDN uses traditional telephone line for connection. You don't need any extra cable connection for it.
• ISDN bandwidth-on-demand feature make it capable of transferring data at 128 Kbps speed.
• Price is low compare to other broadband internet connection.
ISDN Internet Disadvantages
• ISDN is not an always on connection.
• It will be costly if you don't know exact tariffs of phone calls because the charge is per call.
• You can not use ISDN connection when you are traveling.








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