FACTOID # 17: Though Rhode Island is the smallest state in total area, it has the longest official name: The State of Rhode Island and Providence Plantations.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Traffic shaping


Traffic shaping (also known as "packet shaping") is an attempt to control computer network traffic in order to optimize or guarantee performance, low latency, and/or bandwidth by delaying packets[1]. Traffic shaping deals with concepts of classification, queue disciplines, enforcing policies, congestion management, quality of service (QoS), and fairness. For the scientific and engineering discipline studying computer networks, see Computer networking. ... -1... In the fields of packet-switched networks and computer networking, the traffic engineering term Quality of Service (QoS) refers to control mechanisms that can provide different priority to different users or data flows, or guarantee a certain level of performance to a data flow in accordance with requests from the...

Contents

Summary

Traffic shaping provides a mechanism to control the volume of traffic being sent into a network (bandwidth throttling), and the rate at which the traffic is being sent (rate limiting). For this reason, traffic shaping schemes are commonly implemented at the network edges to control traffic entering the network. This control can be accomplished in many ways and for many reasons but traffic shaping always simply consists in delaying packets. Traffic policing is the related practice of packet dropping and packet marking. Traffic shaping can be applied by the traffic source (for example, computer or network card) or by an element in the network. For the scientific and engineering discipline studying computer networks, see Computer networking. ... Bandwidth throttling is a method of ensuring a bandwidth intensive device, such as a server, will limit (throttle) the number of requests it will respond to within a specified period of time. ... In computer networks, rate limiting is the function of controlling the maximum rate of traffic sent or received on a network interface. ... An application that wishes to use the broadband network to transport traffic must first request a connection, which involves informing the network about the characteristics of the traffic and the Quality of Service (QOS) required by the application [1]. This information is stored in a traffic contract. ... A network card, network adapter or NIC (network interface controller) is a piece of computer hardware designed to allow computers to communicate over a computer network. ...


Implementation

A traffic shaper works by delaying metered traffic such that each packet complies with the relevant traffic contract. Metering may be implemented with for example the leaky bucket or token bucket algorithms (the former typically in ATM and the latter in IP networks). Metered packets or cells are then stored in a buffer until they can be transmitted in compliance with the prevailing traffic contract. This may occur immediately (if the traffic arriving at the shaper is already compliant), after some delay (waiting in the buffer until its scheduled release time) or never (in case of buffer overflow). If a service (or application) wishes to use a broadband network (an ATM network in particular) to transport a particular kind of traffic, it must first inform the network about what kind of traffic is to be transported, and the performance requirements of that traffic[1]. The application presents this... Although the leaky bucket algorithm has several uses, it is best understood in the context of network traffic shaping or rate limiting. ... Although the token bucket algorithm has several uses, it is best understood in the context of network traffic shaping or rate limiting. ... Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and data link layer protocol which encodes data traffic into small (53 bytes; 48 bytes of data and 5 bytes of header information) fixed-sized cells. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ... Wiktionary has related dictionary definitions, such as: buffer Buffer can refer to: Buffer state, a country lying between two potentially hostile greater powers, thought to prevent conflict between them Buffer zone, any area that keeps two or more other areas distant from one another, may be demilitarized Buffer (rail transport...


Overflow Condition

All traffic shaper implementations have a finite buffer, and must cope with the case where the buffer is full . A simple and common approach is to drop traffic arriving while the buffer is full (tail drop), thus resulting in traffic policing as well as shaping. A more sophisticated implementation could apply a dropping algorithm such as Random Early Discard; a crude alternative would be to allow overflowing traffic through unshaped. Random early detection (RED) is a queue management algorithm. ...


Traffic Classification

Simple traffic shaping schemes shape all traffic uniformly by rate. More sophisticated shapers first classify traffic. 'Traffic classification categorises traffic (for example, based on port number or protocol number); each resulting traffic class can be treated differently to differentiate service. For example, each traffic class could be subject to a different rate limit, shaped separately and/or prioritised relative to other traffic classes. This differentiation can be used by a network operator to treat different types of application traffic differently (for example, prioritise voice over file sharing), and to offer premium services at a higher price point than basic ones[2]. In computing, a port (derived from seaport) is usually an interface through which data are sent and received. ...


Classification is achieved by various means. Matching bit patterns of data to those of known protocols is a simple, yet widely-used technique. An example to match the BitTorrent Protocol Handshaking phase would be a simple check to see if a packet began with character 19 which was then followed by the 19-byte string 'BitTorrent protocol'.[3] Upon classifying a traffic flow using a particular protocol, a policy can be applied to it and other flows to either guarantee a certain quality (as with VoIP or media streaming service[4]) or to provide best-effort delivery. This may be applied at the ingress point (the point at which traffic enters the network) with a granularity that allows the traffic-shaping control mechanism to separate traffic into individual flows and shape them differently [5]. This article is about the protocol. ... This article does not cite any references or sources. ... how VoIP works A typical analog telephone adapter for connecting an ordinary phone to a VoIP network Ciscos implementation of VoIP - IP Phone Voice over Internet Protocol, also called VoIP, IP Telephony, Internet telephony, Broadband telephony, Broadband Phone and Voice over Broadband is the routing of voice conversations over...


Relationship to Traffic Management

Traffic shaping is a specific technique and one of several which combined comprise Traffic Management[6]. Current common usage, particularly in discussion of domestic Internet service provision, frequently confuses traffic shaping with traffic management and traffic policing, with classification policies and in general with any measure deliberately taken by an ISP which is detrimental to the user's IP traffic performance.


ISPs

Traffic shaping is of interest especially to Internet Service Providers (ISPs). Their high-cost, high-traffic networks are their major assets, and as such, are the focus of all their attentions. They often use traffic shaping as a method to optimize the use of their network, sometimes by intelligently shaping traffic according to importance, other times by discouraging uses of applications by harsh means.[citation needed] “ISP” redirects here. ...


Benefits

To ISPs, mere protocol identification (a large part of modern traffic shaping mechanisms) gives the intangible yet significant benefit of seeing what internet traffic is flowing through the network. From this they can see which subscribers are doing what on their network and can target services to the subscriber base they have attracted.


In addition, intelligent shaping schemes can guarantee a particular Quality of Service (often measured in jitter, packet loss, and latency) for an application or a user while still allowing other traffic to use all remaining bandwidth. This allows ISPs to offer Differentiated services and to upsell existing services to subscribers (such as offering minimum-latency computer gaming for an additional fee on top of basic internet). In telecommunication, jitter is an abrupt and unwanted variation of one or more signal characteristics, such as the interval between successive pulses, the amplitude of successive cycles, or the frequency or phase of successive cycles. ... This page meets Wikipedias criteria for speedy deletion. ... Latency is a time delay between the moment something is initiated, and the moment one of its effects begins. ... This article does not cite any references or sources. ...


Three Types of Traffic

Internet traffic as viewed by ISPs can be thought of as placed into three categories: Sensitive, Best-Effort, and Undesired.


Sensitive Traffic

Sensitive traffic is traffic whose Quality of Service ISPs care about. This usually includes VoIP, online gaming, video streaming, and web surfing, but basically any application or protocol could fall under this umbrella. Shaping schemes are generally tailored in such a way that the Quality of Service of these selected uses is guaranteed, or at least prioritized over other classes of traffic. This can be accomplished by the absence of shaping schemes on these, or by positive shaping (prioritization over others).


Best-Effort Traffic

Best effort traffic is all other kinds of non-detrimental traffic. This is traffic that is either not sensitive to Quality of Service metrics (jitter, packet loss, latency) or traffic that is, and the ISP is not concerned about its Quality of Service. A typical example of the former would be peer-to-peer traffic, the latter: online gaming (though there are exceptions such as [1]). Shaping schemes are generally tailored in such a way that this traffic gets 'what is left' of the bandwidth after sensitive traffic has 'taken its share'. A peer-to-peer (or P2P) computer network is a network that relies on the computing power and bandwidth of the participants in the network rather than concentrating it in a relatively few servers. ...


Undesired Traffic

This category is generally limited to the delivery of spam and traffic created by worms, botnets, and other malicious attacks. In some countries (for example, China), this definition can (and does) expand to such traffic as non-local VoIP (Skype) or video streaming services, which are squelched to create a market for the 'in-house' services of the same type. Shaping schemes usually involve identifying and blocking this traffic entirely, or just by severely hampering its operation. Rogers Communications in Canada has been accused of applying this type of shaping to peer-to-peer traffic in violation of Canadian Radio-television and Telecommunications Commission (CRTC) regulations.[7] Skype (IPA pronunciation: , rhymes with type) is a software program created by the entrepreneurs Niklas Zennström and Janus Friis. ... Rogers Communications Inc. ... The Canadian Radio-television and Telecommunications Commission (CRTC, in French Conseil de la radiodiffusion et des télécommunications canadiennes) was established in 1968 by the Canadian Parliament to replace the Board of Broadcast Governors. ...


Peer-To-Peer

Peer-to-peer (P2P) traffic is particularly troublesome for traffic shaping efforts for ISPs because it is designed to use any and all available bandwidth which impacts QoS-sensitive applications (like online gaming) that use comparatively small amounts of bandwidth. Most, if not all, popular P2P applications are location-agnostic [citation needed](they care not/little if they download from a user halfway around the world or one next door) makes them even more problematic, as traffic outside of a network, which is the more expensive kind, will increase. This article does not cite any references or sources. ...


This has given P2P a bad reputation with internet service providers trying to roll out quality-dependent services (again, like VoIP). Some may even view P2P as an 'attack' on their networks[citation needed].


However, P2P is often listed as the reason subscribers choose broadband internet[citation needed]. Recent figures show that the usage of one-fifth of the highest-usage subscribers must be added together to make up only close to 80% of P2P traffic on ISP networks. [2] Sandvine Incorporated has determined through traffic analysis that P2P traffic accounts for up to 60% of traffic on most networks.[8] This shows, in contrast to previous studies and forecasts, that P2P has become more mainstream than a handful of P2P users on the network. Sandvine Incorporated (TSX: SVC, AIM: SAND), is a networking equipment company based in Waterloo, Ontario, Canada. ...


These figures have influenced service providers to consider subscriber experience when implementing traffic shaping.[citation needed] If P2P is being used by more than the top fifth of an ISP's subscriber base, a harsh anti-P2P policy may have disastrous consequences on subscriber numbers, increasing the subscriber Churn rate. In some extreme cases (like that of Rogers Communications and ihaterogers.ca) this may damage the ISPs reputation permanently. This does not cite any references or sources. ...


P2P protocols are designed specifically to avoid being identified and with enough robustness that it is agnostic to standard QoS metrics (out-of-order packets (jitter) just increase buffering, packet loss and latency just increase the download time) means that it is best classified as Best-Effort traffic. At peak times when sensitive traffic is at its height, download speeds will decrease. However, since P2P downloads are often background activities, it affects the subscriber experience little, so long as the download speeds increase to their full potential when all other subscribers hang up their VoIP phones.


Enterprises

Traffic Shaping and Prioritization is becoming more and more common in the corporate market. Most companies with remote offices are now connected via a WAN (Wide Area Network). Applications tend to become centrally hosted at the head office and remote offices are expected to pull data from central databases and server farms. As applications become more hungry in terms of bandwidth and prices of dedicated circuits being relatively high in most areas of the world, instead of increasing the size of their WAN circuits, companies feel the need to properly manage their circuits to make sure business-oriented traffic gets priority over best-effort traffic. Traffic shaping is thus a good means for companies to avoid purchasing additional bandwidth while properly managing these resources. Wide Area Network (WAN) is a computer network that covers a broad area (i. ...


Other upcoming technologies to this regards are Application Acceleration and WAN Optimization and Compression which are fundamentally different from Traffic Shaping. Traffic Shaping defines bandwidth rules (or partitions as some vendors call them) whereas Application Acceleration using multiple techniques like TCP Performance Enhancing Proxy. WAN Optimization and Compression (WOC) on the other hand would use compression and differential algorithms and techniques to compress data streams or send only differences in file updates. The latter is quite effective for chatty protocols like CIFS. Performance Enhancing Proxies (PEPs) are devices to improve the end-to-end performance of some communications protocol such as TCP. PEPs function by breaking the end-to-end connection into multiple connections and using different parameters to transfer data across the different legs. ... Server message block (SMB) is a network protocol mainly applied to share files, printers, serial ports, and miscellaneous communications between nodes on a network. ...


Uses

Traffic shaping is often used in combination with:

This article does not cite any references or sources. ... In computer networking, IntServ or integrated services is an architecture, which specifies the elements to guarantee quality of service (QoS) on networks. ... Weighted round robin (WRR) is a best-effort connection scheduling discipline. ... Random early detection (RED) is a queue management algorithm. ... Ports on the Apple iBook (Early 2003) In computer hardware, a port serves as an interface between the computer and other computers or devices. ... Tail Drop, or Drop Tail, is a simple queue management algorithm. ... TCP global synchronization in data networking can happen to TCP/IP flows during periods of congestion because each sender will reduce their transmission rate at the same time when packet loss occurs. ... A virtual LAN, commonly known as a VLAN, is a logically segmented network mapped over physical hardware. ...

See also

This article is about the protocol. ... Teletraffic Engineering is a well-understood discipline in the traditional voice network, where traffic patterns are established, growth rates can be predicted, and vast amounts of detailed historical data are available for analysis. ... Network congestion avoidance is a process used in computer networks to avoid congestion. ... In the fields of packet-switched networks and computer networking, the traffic engineering term Quality of Service (QoS) refers to control mechanisms that can provide different priority to different users or data flows, or guarantee a certain level of performance to a data flow in accordance with requests from the... Bandwidth throttling is a method of ensuring a bandwidth intensive device, such as a server, will limit (throttle) the number of requests it will respond to within a specified period of time. ... It has been suggested that layer 4 router be merged into this article or section. ... In computer networks, rate limiting is the function of controlling the maximum rate of traffic sent or received on a network interface. ... Although the token bucket algorithm has several uses, it is best understood in the context of network traffic shaping or rate limiting. ... Although the leaky bucket algorithm has several uses, it is best understood in the context of network traffic shaping or rate limiting. ... Future telecommunication networks should have the following characteristics: broadband, multi-media, multi-point, multi-rate and economical implementation for a diversity of services (multi-services) [1][2]. The Broadband Integrated Services Digital Network (B-ISDN) provides these characteristics to a network. ... The tone or style of this article or section may not be appropriate for Wikipedia. ... Squid is a proxy server and web cache daemon. ... Network neutrality (equivalently net neutrality, Internet neutrality or NN) refers to a principle that is applied to residential broadband networks, and potentially to all networks. ...

Companies With Products Employing Traffic Shaping

Cogeco Cable Inc. ... Crescendo Networks is an Israeli company dealing in the Application Front End Acceleration market. ... F5 Networks, Inc. ... Juniper Networks NASDAQ: JNPR is a telecommunications equipment company. ... NetEqualizer appliances are bandwidth shaping systems designed for voice and data networks developed by APconnections. ... Nortel Networks Corporation TSX: NT NYSE: NT, formerly known as Northern Telecom Limited and now known simply as Nortel, is a multinational telecommunications equipment manufacturer headquartered in Toronto, Canada. ... “Cisco” redirects here. ... Categories: | ... Packeteer (NASDAQ: PKTR), founded in 1996 by Craig Elliott, is an I.T. company based in Cupertino, CA listed on the NASDAQ. Hardware products focus on Application Traffic Management and optimization for wide area networks. ... Radware (NASDAQ: RDWR), engages in the development, manufacture, and sale of intelligent application switching solutions worldwide. ... Riverbed Technology, Inc. ... Sandvine Incorporated (TSX: SVC, AIM: SAND), is a networking equipment company based in Waterloo, Ontario, Canada. ... Tellabs, Inc. ... TurnTide Inc. ... Symantec Corporation NASDAQ: SYMC, founded in 1982, is an international corporation which sells computer software, particularly in the realms of security and information management. ...

Major Internet Service Providers Using Traffic Shaping

Rogers Communications Inc. ... Clearwire is a wireless broadband Internet service provider (ISP) headquartered in Kirkland, Washington. ... Comcast Corporation, NASDAQ: CMCSA based in Philadelphia, Pennsylvania, is both the largest cable company and the largest broadband (2nd overall) Internet Service Provider in the United States. ... Shaw is Canadas second largest cable television operator, after Rogers Communications. ... Cogeco Cable Inc. ... Insight Commuications in a cable provider in the United States. ... Road Runner is a nationwide Internet service provider focused on providing service over DOCSIS-compatible cable modems. ... Time Warner Cable (NYSE: TWC) is an American national cable television company that operates in 27 states and has 31 operating divisions. ... PIPEX Communications PLC is an Internet Service Provider in the United Kingdom. ... TM Net headquarters TM Net is a Malaysian ISP which is a wholly owned subsidiary of TM Bhd. ... PlusNet is an Internet Service Provider (ISP) based in Sheffield in the UK and owned as of 2006 by BT Group. ... Eclipse Internet is a UK Internet Service Provider based out of Exeter, Devon. ... BT Group plc (formerly British Telecommunications plc) which trades as BT (pronounced Bee tee) (also previously as British Telecom and is still commonly known as such amongst the general public) is the privatised UK state telecommunications operator. ... Virgin Media Inc. ... Clearwire is a wireless broadband Internet service provider (ISP) headquartered in Kirkland, Washington. ... TalkTalk is the consumer telephone business of The Carphone Warehouse Group plc. ... TV Cabo, a subsidiary of PT Multimedia, is the leader in the Portuguese pay-tv market and one of the most important operators in Europe. ... Telenet is the largest provider of broadband cable services in Belgium. ... The Carphone Warehouse Group PLC (LSE: CPW), known as The Carphone Warehouse, is Europes largest independent mobile phone retailer, with over 1,700 stores across Europe. ... UPC-Astral is a Romanian telecommunications company, a cable television network, internet service provider and telephone operator. ...

References

  1. ^ IETF RFC 2475 "An Architecture for Differentiated Services" section 2.3.3.3 - definition of "Shaper"
  2. ^ PlusNet's Traffic Classes show classification and prioritisation policies used to differentiate between more and less expensive Internet service
  3. ^ BitTorrent Protocol
  4. ^ SIN 450 Issue 1.2 May 2007 Suppliers' Information Note For The BT Network BT Wholesale - BT IPstream Advanced Services - End User Speed Control and Downstream Quality of Service - Service Description
  5. ^ Ferguson P., Huston G., Quality of Service: Delivering QoS on the Internet and in Corporate Networks, John Wiley & Sons, Inc., 1998. ISBN 0-471-24358-2.
  6. ^ ATM Forum Traffic Management Specification, Version 4.0 Approved Specification 0056.00, Section 5.5, Traffic Shaping
  7. ^ Geist, Michael. The Unintended Consequences of Rogers' Packet Shaping.
  8. ^ Leydon, John. P2P swamps broadband networks.
  • "Deploying IP and MPLS QoS for Multiservice Networks: Theory and Practice" by John Evans, Clarence Filsfils (Morgan Kaufmann, 2007, ISBN 0-12-370549-5)
  • "Peer-to-Peer File Sharing: The Impact of File Sharing on Service Provider Networks", Sandvine Incorporated, copyright 2002

External links


  Results from FactBites:
 
Traffic Shaping (370 words)
Traffic shaping is an attempt to control computer network traffic in order to optimize or guarantee performance, low latency, and/or bandwidth.
Traffic shaping provides a mechanism to control the volume of traffic being sent into a network (bandwidth throttling), and the rate at which the traffic is being sent (rate limiting).
For this reason, traffic shaping schemes need to be implemented at the network edges to control the traffic entering the network.
Traffic Shaping (3436 words)
All four traffic shaping methods are similar in implementation, though their command line interfaces (CLIs) differ somewhat and they use different types of queues to contain and shape traffic that is deferred.
Traffic shaping allows you to control outgoing traffic on an interface to match the traffic speed of the remote target interface and to ensure that the traffic conforms to specific policies.
Peak and average traffic shaping is configured on a per-interface or per-class basis, and cannot be used in conjunction with commands used to configure GTS from previous versions of Cisco IOS.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m