Bandwidth throttling
Encyclopedia
Bandwidth throttling is a reactive measure employed in communication networks 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. This can be used to actively limit a user's upload and download rates on programs such as 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 to spread 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
.
, which host data and provide services to clients
. The Internet is a good example, in which web server
s 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.
, 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 ISP's, Cox and Comcast, have stated that they engage in this practice, where they limit users' bandwidth by up to 99%. Today most if not all Internet Service Providers throttle their users bandwidth, with or without the user ever even realizing it. In the specific case of Comcast
, an equipment vendor called Sandvine
developed the network management technology that throttled P2P file transfers. Comcast was not even the originator of the "throttling" technique.
Those that could have their bandwidth throttled are typically someone who is constantly downloading and uploading torrents, or someone that 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 ISP's. By throttling the people who are using so much bandwidth, the ISPs enable their regular users to have a better overall quality of service.
is the guiding principle that preserves the free and open Internet. Net Neutrality means that Internet service providers may not discriminate between different kinds of content and applications online. It guarantees a level playing field for all Web sites and Internet technologies. With Net Neutrality, the network's only job is to move data -- not to choose which data to privilege with higher quality service. The network neutrality principle protects the consumer's right to use any equipment, content, application or service without interference from the network provider.
) accepts data. If this limit is not in place, the device can overload its processing capacity.
Contrary to throttling, in order to use bandwidth when available, but prevent excess, each node in a proactive system should set an outgoing bandwidth cap that appropriately limits the total number of bytes sent per unit time. There are two types of bandwidth capping. A standard cap limits the bitrate
or speed of data transfer on a broadband internet connection. Standard capping is used to prevent individuals from consuming the entire transmission capacity of the medium. A lowered cap reduces an individual user’s bandwidth cap as a defensive measure and/or as a punishment for heavy use of the medium’s bandwidth
. Sometimes this happens without notifying the user.
The difference is that bandwidth throttling regulates a bandwidth intensive device (such as a server
) by limiting how much data that device can accept or receive. Bandwidth capping on the other hand limits the total transfer capacity, upstream or downstream, of data over a medium.
took steps to ease network congestion by interfering with peer-to-peer traffic. Specifically, it falsified packets of data that fooled users and their peer-to-peer programs into thinking they were transferring files. Comcast initially denied that it interfered with its subscribers’ uploads, but later admitted it. The FCC held a hearing and concluded that Comcast violated the principles of the Internet Policy Statement because Comcast’s “discriminatory and arbitrary practice unduly squelched the dynamic benefits of an open and accessible Internet and did not constitute reasonable network management.” The FCC also provided clear guidelines to any ISP wishing to engage in reasonable network management. The FCC suggested ways that Comcast could have achieved its goal of stopping network congestion, including capping the average user’s capacity and charging the most aggressive users overage fees, throttling back the connections of all high capacity users, or negotiating directly with the application providers and developing new technologies.
However, in 2008 Comcast
amended their Acceptable Usage Policy and placed a specific 250 GB monthly cap in an attempt to constrain excessive bandwidth users. Comcast has also announced a new bandwidth-throttling plan. The scheme includes a two-class system of Priority-best-effort and best-effort where “sustained use of 70% of your up or downstream throughput triggers the BE state, at which point you'll find your traffic priority lowered until your usage drops to 50% of your provisioned upstream or downstream bandwidth for "a period of approximately 15 minutes." A throttled Comcast user being placed in a BE state "may or may not result in the user's traffic being delayed or, in extreme cases, dropped before PBE traffic is dropped." Comcast explained to the FCC that “If there is no congestion, packets from a user in a BE state should have little trouble getting on the bus when they arrive at the bus stop. If, on the other hand, there is congestion in a particular instance, the bus may become filled by packets in a PBE state before any BE packets can get on. In that situation, the BE packets would have to wait for the next bus that is not filled by PBE packets. “
to single out P2P
traffic for bandwidth throttling between the hours of 4:30pm to 2am.
ISP's in Canada that currently throttle bandwidth:
launched an investigation into internet service providers’ methods for managing traffic on their networks. Some ISPs, for instance, restrict access to services such as Skype
or the BBC iPlayer at peak times so that their users all receive an equal service. The EU's commissioner for the digital agenda, Neelie Kroes, said: "I am absolutely determined that everyone in the EU should have the chance to enjoy the benefits of an open and lawful internet, without hidden restrictions or slower speeds than they have been promised.” The Body of European Regulators for Electronic Communications (Berec) will examine the issues for the EU, and will ask both businesses and consumers for their views. The EU will publish the results of its investigation by the end of 2011.
Län
Län and lääni refer to the administrative divisions used in Sweden and previously in Finland. The provinces of Finland were abolished on January 1, 2010....
), a sysadmin may employ bandwidth throttling to help limit network congestion and server crashes. On a broader level, the Internet Service Provider
Internet service provider
An Internet service provider is a company that provides access to the Internet. Access ISPs directly connect customers to the Internet using copper wires, wireless or fiber-optic connections. Hosting ISPs lease server space for smaller businesses and host other people servers...
may use bandwidth throttling to help reduce a user's usage of bandwidth that is supplied to the local network. This can be used to actively limit a user's upload and download rates on programs such as 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
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
applications, in order to spread 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
Crash (computing)
A crash in computing is a condition where a computer or a program, either an application or part of the operating system, ceases to function properly, often exiting after encountering errors. Often the offending program may appear to freeze or hang until a crash reporting service documents...
.
Operation
A computer network typically consists of a number of serversServer (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
, which host data and provide services to clients
Client (computing)
A client is an application or system that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the service by way of a network....
. The Internet is a good example, in which web server
Web server
Web server can refer to either the hardware or the software that helps to deliver content that can be accessed through the Internet....
s 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
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
. 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
Server administrator
----A server administrator, or admin has the overall control of a server. This can be in the context of a business organization, where often a server administrator oversees the performance and condition of multiple servers in the business, or it can be in the context of a single person running a...
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 serverServer (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
, 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
Deep packet inspection
Deep Packet Inspection is a form of computer network packet filtering that examines the data part of a packet as it passes an inspection point, searching for protocol non-compliance, viruses, spam, intrusions or predefined criteria to decide if the packet can...
(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 ISP's, Cox and Comcast, have stated that they engage in this practice, where they limit users' bandwidth by up to 99%. Today most if not all Internet Service Providers throttle their users bandwidth, with or without the user ever even realizing it. In the specific case of Comcast
Comcast
Comcast Corporation is the largest cable operator, home Internet service provider, and fourth largest home telephone service provider in the United States, providing cable television, broadband Internet, and telephone service to both residential and commercial customers in 39 states and the...
, an equipment vendor called Sandvine
Sandvine
Sandvine Incorporated , in Waterloo, Ontario, Canada.Sandvine network policy control products are designed to implement broad network policies, ranging from service creation, billing, congestion management, and security...
developed the network management technology that throttled P2P file transfers. Comcast was not even the originator of the "throttling" technique.
Those that could have their bandwidth throttled are typically someone who is constantly downloading and uploading torrents, or someone that 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 ISP's. By throttling the people who are using so much bandwidth, the ISPs enable their regular users to have a better overall quality of service.
Network Neutrality
Network NeutralityNetwork neutrality
Network neutrality is a principle that advocates no restrictions by Internet service providers or governments on consumers' access to networks that participate in the Internet...
is the guiding principle that preserves the free and open Internet. Net Neutrality means that Internet service providers may not discriminate between different kinds of content and applications online. It guarantees a level playing field for all Web sites and Internet technologies. With Net Neutrality, the network's only job is to move data -- not to choose which data to privilege with higher quality service. The network neutrality principle protects the consumer's right to use any equipment, content, application or service without interference from the network provider.
Throttling vs. Capping
Bandwidth throttling works by limiting (throttling) the rate at which a bandwidth intensive device (a serverServer (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
) accepts data. If this limit is not in place, the device can overload its processing capacity.
Contrary to throttling, in order to use bandwidth when available, but prevent excess, each node in a proactive system should set an outgoing bandwidth cap that appropriately limits the total number of bytes sent per unit time. There are two types of bandwidth capping. A standard cap limits the bitrate
Bitrate
In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....
or speed of data transfer on a broadband internet connection. Standard capping is used to prevent individuals from consuming the entire transmission capacity of the medium. A lowered cap reduces an individual user’s bandwidth cap as a defensive measure and/or as a punishment for heavy use of the medium’s bandwidth
Bandwidth
Bandwidth is the difference between the upper and lower frequencies in a contiguous set of frequencies. It is typically measured in hertz, and may sometimes refer to passband bandwidth, sometimes to baseband bandwidth, depending on context...
. Sometimes this happens without notifying the user.
The difference is that bandwidth throttling regulates a bandwidth intensive device (such as a server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
) by limiting how much data that device can accept or receive. Bandwidth capping on the other hand limits the total transfer capacity, upstream or downstream, of data over a medium.
Comcast Corporation vs. FCC and U.S.
In 2007, the Free Press and Public Knowledge, along with the Federal Communications Commission, filed a complaint against Comcast’s Internet service. Several subscribers claimed that the company was interfering with their use of peer-to-peer networking applications. The Commission it had jurisdiction over Comcast’s network management practices and that it could resolve the dispute through negotiation rather than through rulemaking. The Commission believed that Comcast has “significantly impeded consumers’ ability to access the content and use the applications of their choice”, and that because Comcast “ha[d] several available options it could use to manage network traffic without discriminating” against peer-to-peer communications, its method of bandwidth management “contravene[d] . . . federal policy,”. At this time, “Comcast had already agreed to adopt a new system for managing bandwidth demand, the Commission simply ordered it to make a set of disclosures describing the details of its new approach and the company’s progress toward implementing it.” Comcast complied with this Order but petitioned for a review and presented several objections. “First, it contends that the Commission has failed to justify exercising jurisdiction over its network management practices. Second, it argues that the Commission’s adjudicatory action was procedurally flawed because it circumvented the rulemaking requirements of the Administrative Procedure Act and violated the notice requirements of the Due Process Clause. Finally, it asserts that parts of the Order are so poorly reasoned as to be arbitrary and capricious.” In 2010, the court decided that “because the Commission has failed to tie its assertion of ancillary authority over Comcast’s Internet service to any “statutorily mandated responsibility,” Comcast would be granted the petition for review and the Order would be cleared.United States
In 2007, ComcastComcast
Comcast Corporation is the largest cable operator, home Internet service provider, and fourth largest home telephone service provider in the United States, providing cable television, broadband Internet, and telephone service to both residential and commercial customers in 39 states and the...
took steps to ease network congestion by interfering with peer-to-peer traffic. Specifically, it falsified packets of data that fooled users and their peer-to-peer programs into thinking they were transferring files. Comcast initially denied that it interfered with its subscribers’ uploads, but later admitted it. The FCC held a hearing and concluded that Comcast violated the principles of the Internet Policy Statement because Comcast’s “discriminatory and arbitrary practice unduly squelched the dynamic benefits of an open and accessible Internet and did not constitute reasonable network management.” The FCC also provided clear guidelines to any ISP wishing to engage in reasonable network management. The FCC suggested ways that Comcast could have achieved its goal of stopping network congestion, including capping the average user’s capacity and charging the most aggressive users overage fees, throttling back the connections of all high capacity users, or negotiating directly with the application providers and developing new technologies.
However, in 2008 Comcast
Comcast
Comcast Corporation is the largest cable operator, home Internet service provider, and fourth largest home telephone service provider in the United States, providing cable television, broadband Internet, and telephone service to both residential and commercial customers in 39 states and the...
amended their Acceptable Usage Policy and placed a specific 250 GB monthly cap in an attempt to constrain excessive bandwidth users. Comcast has also announced a new bandwidth-throttling plan. The scheme includes a two-class system of Priority-best-effort and best-effort where “sustained use of 70% of your up or downstream throughput triggers the BE state, at which point you'll find your traffic priority lowered until your usage drops to 50% of your provisioned upstream or downstream bandwidth for "a period of approximately 15 minutes." A throttled Comcast user being placed in a BE state "may or may not result in the user's traffic being delayed or, in extreme cases, dropped before PBE traffic is dropped." Comcast explained to the FCC that “If there is no congestion, packets from a user in a BE state should have little trouble getting on the bus when they arrive at the bus stop. If, on the other hand, there is congestion in a particular instance, the bus may become filled by packets in a PBE state before any BE packets can get on. In that situation, the BE packets would have to wait for the next bus that is not filled by PBE packets. “
Canada
In 2008, the Canadian Radio-television and Telecommunications Commission (CRTC) famously decided to allow Bell CanadaBell Canada
Bell Canada is a major Canadian telecommunications company. Including its subsidiaries such as Bell Aliant, Northwestel, Télébec, and NorthernTel, it is the incumbent local exchange carrier for telephone and DSL Internet services in most of Canada east of Manitoba and in the northern territories,...
to single out P2P
Peer-to-peer
Peer-to-peer computing or networking is a distributed application architecture that partitions tasks or workloads among peers. Peers are equally privileged, equipotent participants in the application...
traffic for bandwidth throttling between the hours of 4:30pm to 2am.
ISP's in Canada that currently throttle bandwidth:
- Bell Canada: Yes (only P2P between 4:30pm and 2am)
- Cogeco Cable: Yes
- MTS Allstream: No
- Rogers Cable: Yes
- Saskatchewan Telecom: No
- Primus Telecom: No
- Shaw: Yes
- Barrett Xplore: Yes, and also prioritizes VoIP
- TELUS: No
- Bragg: Confidential
- Teksavvy Cable: No
- Teksavvy DSL: Yes (only P2P between 4:30pm and 2am)
- Teksavvy DSL MLPPP: No
Europe
In April of 2011, the European UnionEuropean Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
launched an investigation into internet service providers’ methods for managing traffic on their networks. Some ISPs, for instance, restrict access to services such as Skype
Skype
Skype is a software application that allows users to make voice and video calls and chat over the Internet. Calls to other users within the Skype service are free, while calls to both traditional landline telephones and mobile phones can be made for a fee using a debit-based user account system...
or the BBC iPlayer at peak times so that their users all receive an equal service. The EU's commissioner for the digital agenda, Neelie Kroes, said: "I am absolutely determined that everyone in the EU should have the chance to enjoy the benefits of an open and lawful internet, without hidden restrictions or slower speeds than they have been promised.” The Body of European Regulators for Electronic Communications (Berec) will examine the issues for the EU, and will ask both businesses and consumers for their views. The EU will publish the results of its investigation by the end of 2011.
Workarounds For Bandwidth Throttling
Although ISP's may actively throttle bandwidth, there are several known methods to bypass the throttling of a user's bandwidth. These methods include:- Virtual Private NetworkVirtual private networkA virtual private network is a network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network....
(VPN) - Generally cost a monthly fee to rent, but offers users a secure connection where data cannot be intercepted. - Force Encryption - Free method that works for some users.
- SeedboxSeedboxA seedbox is a private dedicated server used for the uploading and downloading of digital files.Seedboxes generally make use of the BitTorrent protocol for uploading and downloading, although they have also been used on the eDonkey2000 network. Seedboxes are usually connected to a high speed...
- A dedicated private server, usually hosted offshore, that offers high speed upstream and downstream rates and often storage for a relatively high monthly cost. - SSH Tunneling - Tunneling protocolTunneling protocolComputer networks use a tunneling protocol when one network protocol encapsulates a different payload protocol...
See also
- Bandwidth capBandwidth capA bandwidth cap, also known as a bit cap, limits the transfer of a specified amount of data over a period of time. Internet service providers commonly apply a cap when a channel intended to be shared by many users becomes overloaded, or may be overloaded, by a few users...
- Bandwidth managementBandwidth managementBandwidth management is the process of measuring and controlling the communications on a network link, to avoid filling the link to capacity or overfilling the link, which would result in network congestion and poor performance of the network.- Management :Bandwidth management mechanisms may be...
- Traffic shapingTraffic shapingTraffic shaping is the control of computer network traffic in order to optimize or guarantee performance, improve latency, and/or increase usable bandwidth for some kinds of packets by delaying other kinds of packets that meet certain criteria...
- Rate limitingRate limitingIn computer networks, rate limiting is used to control the rate of traffic sent or received on a network interface. Traffic that is less than or equal to the specified rate is sent, whereas traffic that exceeds the rate is dropped or delayed...
- Network NeutralityNetwork neutralityNetwork neutrality is a principle that advocates no restrictions by Internet service providers or governments on consumers' access to networks that participate in the Internet...
- Data discriminationData discriminationData discrimination is the selective filtering of information by a service provider. This has been an new issue in the recent debate over network neutrality...