Bandwidth Throttling, What is ?

Bandwidth throttling is the intentional slowing of Internet service by an Internet service provider . It is a reactive measure employed in communication networks in an apparent attempt to regulate network traffic and minimize bandwidth congestion. Bandwidth throttling can occur at different locations on
the network. On a local area network ( LAN), a sysadmin may employ bandwidth throttling to help limit network congestion and server crashes. On a broader level, the Internet service provider may use bandwidth throttling to help reduce a user's usage of bandwidth that is supplied to the local network.
Throttling can be used to actively limit a
user's upload and download rates on
programs such as video streaming, BitTorrent
protocols and other file sharing applications,
as well as even out the usage of the total bandwidth supplied across all users on the network. Bandwidth throttling is also often
used in Internet applications, in order tospread a load over a wider network to reduce local network congestion, or over a number of servers to avoid overloading individual ones, and so reduce their risk of crashing, and gain additional revenue by compelling users to use more expensive pricing schemes where bandwidth is not throttled.

Operation
A computer network typically consists of a number of servers, which host data and provide services to clients . The Internet is a good example, in which web servers are used to host websites, providing information to a
potentially very large number of client
computers. Clients will make requests to servers, which will respond by sending the required data. As there will typically be many clients per server, the data processing demand on a server will generally be considerably greater than on any individual client. And so servers are typically implemented using computers with high data capacity and processing power. The traffic on such a network will vary over time, and there will be periods when client requests will peak, sometimes exceeding the capacity of parts of network and causing congestion, especially in parts of the network that form bottlenecks . This can cause data
request failures, or in worst cases, server crashes.
In order to prevent such occurrences, a server administrator may implement bandwidth throttling to control the number of requests a server responds to within a specified period of time.
When a server using bandwidth throttling reaches the specified limit, it will offload new requests and not respond to them. Sometimes they may be added to a queue to be processed once the bandwidth use reaches an acceptable level, but at peak times the request rate can even exceed the capacities of such queues and requests have to be thrown away.

Application
A bandwidth intensive device, such as a
server, might limit, or throttle, the rate at
which it accepts data, in order to avoid
overloading its processing capacity. This can
be done both at the local network servers or
at the ISP servers. ISPs often employ deep
packet inspection (DPI), which is widely
available in routers or provided by special DPI
equipment. Additionally, today’s networking
equipment allows ISPs to collect statistics on
flow sizes at line speed, which can be used to
mark large flows for traffic shaping. Two
ISPs, Cox and Comcast, have stated that they
engage in this practice, where they limit users'
bandwidth by up to 99%. [2] Today most if not
all Internet Service Providers throttle their
users' bandwidth, with or without the user ever
even realizing it. [3] In the specific case of
Comcast, an equipment vendor called
Sandvine developed the network management
technology that throttled P2P file transfers. [4]
Those that could have their bandwidth
throttled are typically someone who is
constantly downloading and uploading
torrents, or someone who just watches a lot of
online videos. Many consider this as an unfair
method of regulating the bandwidth because
consumers not getting the required bandwidth
even after paying the prices set by the ISPs.
By throttling the people who are using so
much bandwidth, the ISPs enable their regular
users to have a better overall quality of
service