The most common type of traffic shaping is application-based traffic shaping.[4][failed verification] In application-based traffic shaping, fingerprinting tools are first used to identify applications of interest, which are then subject to shaping policies. Some controversial cases of application-based traffic shaping include bandwidth throttling of peer-to-peer file sharing traffic. Many application protocols use encryption to circumvent application-based traffic shaping.
Another type of traffic shaping is route-based traffic shaping. Route-based traffic shaping is conducted based on previous-hop or next-hop information.[5]
If a link becomes utilized to the point where there is a significant level of congestion, latency can rise substantially. Traffic shaping can be used to prevent this from occurring and keep latency in check. Traffic shaping provides a means to control the volume of traffic being sent into a network in a specified period (bandwidth throttling), or the maximum rate at which the traffic is sent (rate limiting), or more complex criteria such as generic cell rate algorithm. This control can be accomplished in many ways and for many reasons; however traffic shaping is always achieved by delaying packets.
Traffic shaping is commonly applied at the network edges to control traffic entering the network, but can also be applied by the traffic source (for example, computer or network card[6]) or by an element in the network.
Uses
Traffic shaping is sometimes applied by traffic sources to ensure the traffic they send complies with a contract which may be enforced in the network by traffic policing.
Shaping is widely used for teletraffic engineering, and appears in domestic ISPs' networks as one of several Internet Traffic Management Practices (ITMPs).[7] Some ISPs may use traffic shaping to limit resources consumed by peer-to-peer file-sharing networks, such as BitTorrent.[8]
Data centers use traffic shaping to maintain service level agreements for the variety of applications and the many tenants hosted as they all share the same physical network.[9]
Audio Video Bridging includes an integral traffic-shaping provision defined in IEEE 802.1Qav.
Nodes in an IP network which buffer packets before sending on a link which is at capacity produce an unintended traffic shaping effect. This can appear across, for example, a low bandwidth link, a particularly expensive WAN link or satellite hop.
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 FIFO buffer, one for each separately shaped class, until they can be transmitted in compliance with the associated traffic contract. Transmission 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 packet loss).
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 a strategy known as tail drop and which results in traffic policing as well as shaping. A more sophisticated implementation could apply a dropping algorithm such as random early detection.
Traffic classification
Simple traffic shaping schemes shape all traffic uniformly. More sophisticated shapers first classify traffic. Traffic classification categorises traffic (for example, based on port number or protocol). Different classes can then be shaped separately to achieve a desired effect.
Self-limiting sources
A self-limiting source produces traffic which never exceeds some upper bound, for example media sources which cannot transmit faster than their encoded rate allows.[10] Self-limiting sources shape the traffic they generate to a greater or lesser degree. Congestion control mechanisms can also affect traffic shaping of sorts - for example TCP's window mechanism implements a variable rate constraint related to bandwidth-delay product.
TCP Nice, a modified version of TCP developed by researchers at the University of Texas at Austin, allows applications to request that certain TCP connections be managed by the operating system as near zero-cost background transfers, or nice flows. Such flows interfere only minimally with foreground (non-nice) flows, while reaping a large fraction of spare network bandwidth.[11]
Relationship to bandwidth management
Traffic shaping is a specific technique and one of several which combined constitute bandwidth management.[12]
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 their attentions. They sometimes use traffic shaping to optimize the use of their network, sometimes by shaping traffic according to their assessment of importance and thus discouraging use of certain applications.[13]
Most companies with remote offices are now connected via a wide area network (WAN). Applications tend to be 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 other traffic. Traffic shaping is thus a good means for companies to avoid purchasing additional bandwidth while properly managing these resources.
Alternatives to traffic shaping in this regard are application acceleration and WAN optimization and compression, which are fundamentally different from traffic shaping. Traffic shaping defines bandwidth rules whereas application acceleration using multiple techniques like a TCP performance-enhancing proxy. WAN optimization, on the other hand, compresses data streams or sends only differences in file updates. The latter is quite effective for chatty protocols like CIFS.
Traffic shaping detection
There are several methods to detect and measure traffic shaping. Tools have been developed to assist with detection.[14][15]
^IETF RFC 2475 "An Architecture for Differentiated Services" section 2.3.3.3 - Internet standard definition of "Shaper"
^ITU-T Recommendation I.371: Traffic control and congestion control in B-ISDN Section 7.2.7 defines traffic shaping as a traffic control mechanism which "alters the traffic characteristics of a stream of cells on a VCC or a VPC to achieve a desired modification of those traffic characteristics, in order to achieve better network efficiency whilst meeting the QoS objectives or to ensure conformance at a subsequent interface. ... Shaping modifies traffic characteristics of a cell flow with the consequence of increasing the mean cell transfer delay."
^"Cisco Tech Notes: Comparing Traffic Policing and Traffic Shaping for Bandwidth Limiting. Document ID: 19645". Cisco Systems. Aug 10, 2005. Retrieved 2014-03-08. Graphs illustrate differences in typical output
^Dischinger, Marcel; Mislove, Alan; Haeberlen, Andreas; Gummadi, Krishna P. (October 2008). "Detecting BitTorrent Blocking" (PDF). Proceedings of the 8th ACM SIGCOMM conference on Internet measurement conference - IMC '08. ACM Internet Measurement Conference 2008. p. 3. doi:10.1145/1452520.1452523. ISBN978-1-60558-334-1. S2CID 429226.
^Ascertaining the Reality of Network Neutrality Violation in Backbone ISPs, ACM HotNets 2008
^IEEE INFOCOM 2001. Arsenic: a user-accessible gigabit Ethernet interface Pratt, I., Fraser, K., Computer Laboratory, Cambridge University; Twentieth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings 2001 Volume 1, pages: 67-76 vol.1. Describes a gigabit Ethernet NIC with transmit traffic shaping.
^Review of the Internet traffic management practices of Internet service providers (Telecom. Reg. Policy CRTC 2009-657) Canadian telecomms regulator CRTC ruling relating to traffic shaping usage by domestic ISPs.
^. FLOSS Manuals. Archived from the original on 14 July 2014. Retrieved 7 March 2014.
^M. Noormohammadpour, C. S. Raghavendra, "Datacenter Traffic Control: Understanding Techniques and Trade-offs," IEEE Communications Surveys & Tutorials, vol. PP, no. 99, pp. 1-1.
^Helzer, Josh; Xu, Lisong (2009-02-27), (PDF), archived from the original (PDF) on 2009-02-27
^Venkataramani, Arun; Kokku, Ravi; Dahlin, Mike. "TCP Nice: Self-tuning Network Support for Background Applications". CiteSeerX10.1.1.81.5905. {{cite journal}}: Cite journal requires |journal= (help)
^ATM Forum Traffic Management Specification, Version 4.0 Approved Specification 0056.00, Section 5.5, Traffic Shaping
^CNet: Is Comcast's BitTorrent filtering violating the law? Analysis of Comcast's impersonation techniques for limiting BitTorrent usage.
John Evans; Clarence Filsfils (2007). Deploying IP and MPLS QoS for Multiservice Networks: Theory and Practice. Morgan Kaufmann. ISBN978-0-12-370549-5.
External links
BBC News - Traffic Shaping and BitTorrent
article comparing traffic management techniques circa 2001
Web based traffic shaping bridge/router
Dynamisches Bandbreitenmanagement im Chemnitzer StudentenNetz (German work about "DynShaper-Software" used at (student network at Chemnitz University of Technology): )
January 06, 2023
traffic, shaping, bandwidth, management, technique, used, computer, networks, which, delays, some, datagrams, bring, them, into, compliance, with, desired, traffic, profile, used, optimize, guarantee, performance, improve, latency, increase, usable, bandwidth,. Traffic shaping is a bandwidth management technique used on computer networks which delays some or all datagrams to bring them into compliance with a desired traffic profile 1 2 Traffic shaping is used to optimize or guarantee performance improve latency or increase usable bandwidth for some kinds of packets by delaying other kinds It is often confused with traffic policing the distinct but related practice of packet dropping and packet marking 3 The most common type of traffic shaping is application based traffic shaping 4 failed verification In application based traffic shaping fingerprinting tools are first used to identify applications of interest which are then subject to shaping policies Some controversial cases of application based traffic shaping include bandwidth throttling of peer to peer file sharing traffic Many application protocols use encryption to circumvent application based traffic shaping Another type of traffic shaping is route based traffic shaping Route based traffic shaping is conducted based on previous hop or next hop information 5 Contents 1 Functionality 2 Uses 3 Implementation 3 1 Overflow condition 3 2 Traffic classification 3 3 Self limiting sources 3 4 Relationship to bandwidth management 4 ISPs and traffic management 5 Enterprises 6 Traffic shaping detection 7 See also 8 References 9 External linksFunctionality EditIf a link becomes utilized to the point where there is a significant level of congestion latency can rise substantially Traffic shaping can be used to prevent this from occurring and keep latency in check Traffic shaping provides a means to control the volume of traffic being sent into a network in a specified period bandwidth throttling or the maximum rate at which the traffic is sent rate limiting or more complex criteria such as generic cell rate algorithm This control can be accomplished in many ways and for many reasons however traffic shaping is always achieved by delaying packets Traffic shaping is commonly applied at the network edges to control traffic entering the network but can also be applied by the traffic source for example computer or network card 6 or by an element in the network Uses EditTraffic shaping is sometimes applied by traffic sources to ensure the traffic they send complies with a contract which may be enforced in the network by traffic policing Shaping is widely used for teletraffic engineering and appears in domestic ISPs networks as one of several Internet Traffic Management Practices ITMPs 7 Some ISPs may use traffic shaping to limit resources consumed by peer to peer file sharing networks such as BitTorrent 8 Data centers use traffic shaping to maintain service level agreements for the variety of applications and the many tenants hosted as they all share the same physical network 9 Audio Video Bridging includes an integral traffic shaping provision defined in IEEE 802 1Qav Nodes in an IP network which buffer packets before sending on a link which is at capacity produce an unintended traffic shaping effect This can appear across for example a low bandwidth link a particularly expensive WAN link or satellite hop Implementation EditA 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 FIFO buffer one for each separately shaped class until they can be transmitted in compliance with the associated traffic contract Transmission 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 packet loss Overflow condition Edit 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 a strategy known as tail drop and which results in traffic policing as well as shaping A more sophisticated implementation could apply a dropping algorithm such as random early detection Traffic classification Edit Simple traffic shaping schemes shape all traffic uniformly More sophisticated shapers first classify traffic Traffic classification categorises traffic for example based on port number or protocol Different classes can then be shaped separately to achieve a desired effect Self limiting sources Edit A self limiting source produces traffic which never exceeds some upper bound for example media sources which cannot transmit faster than their encoded rate allows 10 Self limiting sources shape the traffic they generate to a greater or lesser degree Congestion control mechanisms can also affect traffic shaping of sorts for example TCP s window mechanism implements a variable rate constraint related to bandwidth delay product TCP Nice a modified version of TCP developed by researchers at the University of Texas at Austin allows applications to request that certain TCP connections be managed by the operating system as near zero cost background transfers or nice flows Such flows interfere only minimally with foreground non nice flows while reaping a large fraction of spare network bandwidth 11 Relationship to bandwidth management Edit Traffic shaping is a specific technique and one of several which combined constitute bandwidth management 12 ISPs and traffic management EditSee also Bandwidth throttling Teletraffic engineering and Traffic management 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 their attentions They sometimes use traffic shaping to optimize the use of their network sometimes by shaping traffic according to their assessment of importance and thus discouraging use of certain applications 13 Enterprises EditThis section does not cite any sources Please help improve this section by adding citations to reliable sources Unsourced material may be challenged and removed March 2020 Learn how and when to remove this template message Most companies with remote offices are now connected via a wide area network WAN Applications tend to be 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 other traffic Traffic shaping is thus a good means for companies to avoid purchasing additional bandwidth while properly managing these resources Alternatives to traffic shaping in this regard are application acceleration and WAN optimization and compression which are fundamentally different from traffic shaping Traffic shaping defines bandwidth rules whereas application acceleration using multiple techniques like a TCP performance enhancing proxy WAN optimization on the other hand compresses data streams or sends only differences in file updates The latter is quite effective for chatty protocols like CIFS Traffic shaping detection EditThere are several methods to detect and measure traffic shaping Tools have been developed to assist with detection 14 15 See also EditNetwork congestion avoidance Quality of service Multilayer switch TCP pacing Broadband networks Net neutrality Tc Linux command used to manage traffic shapingReferences Edit IETF RFC 2475 An Architecture for Differentiated Services section 2 3 3 3 Internet standard definition of Shaper ITU T Recommendation I 371 Traffic control and congestion control in B ISDN Section 7 2 7 defines traffic shaping as a traffic control mechanism which alters the traffic characteristics of a stream of cells on a VCC or a VPC to achieve a desired modification of those traffic characteristics in order to achieve better network efficiency whilst meeting the QoS objectives or to ensure conformance at a subsequent interface Shaping modifies traffic characteristics of a cell flow with the consequence of increasing the mean cell transfer delay Cisco Tech Notes Comparing Traffic Policing and Traffic Shaping for Bandwidth Limiting Document ID 19645 Cisco Systems Aug 10 2005 Retrieved 2014 03 08 Graphs illustrate differences in typical output Dischinger Marcel Mislove Alan Haeberlen Andreas Gummadi Krishna P October 2008 Detecting BitTorrent Blocking PDF Proceedings of the 8th ACM SIGCOMM conference on Internet measurement conference IMC 08 ACM Internet Measurement Conference 2008 p 3 doi 10 1145 1452520 1452523 ISBN 978 1 60558 334 1 S2CID 429226 Ascertaining the Reality of Network Neutrality Violation in Backbone ISPs ACM HotNets 2008 IEEE INFOCOM 2001 Arsenic a user accessible gigabit Ethernet interface Pratt I Fraser K Computer Laboratory Cambridge University Twentieth Annual Joint Conference of the IEEE Computer and Communications Societies Proceedings 2001 Volume 1 pages 67 76 vol 1 Describes a gigabit Ethernet NIC with transmit traffic shaping Review of the Internet traffic management practices of Internet service providers Telecom Reg Policy CRTC 2009 657 Canadian telecomms regulator CRTC ruling relating to traffic shaping usage by domestic ISPs HOW TO BYPASS INTERNET CENSORSHIP FLOSS Manuals Archived from the original on 14 July 2014 Retrieved 7 March 2014 M Noormohammadpour C S Raghavendra Datacenter Traffic Control Understanding Techniques and Trade offs IEEE Communications Surveys amp Tutorials vol PP no 99 pp 1 1 Helzer Josh Xu Lisong 2009 02 27 Congestion Control for Multimedia Streaming with Self Limiting Sources PDF archived from the original PDF on 2009 02 27 Venkataramani Arun Kokku Ravi Dahlin Mike TCP Nice Self tuning Network Support for Background Applications CiteSeerX 10 1 1 81 5905 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help ATM Forum Traffic Management Specification Version 4 0 Approved Specification 0056 00 Section 5 5 Traffic Shaping CNet Is Comcast s BitTorrent filtering violating the law Analysis of Comcast s impersonation techniques for limiting BitTorrent usage ShaperProbe Retired Glasnost Retired John Evans Clarence Filsfils 2007 Deploying IP and MPLS QoS for Multiservice Networks Theory and Practice Morgan Kaufmann ISBN 978 0 12 370549 5 External links EditBBC News Traffic Shaping and BitTorrent IT world com Traffic Shaping article comparing traffic management techniques circa 2001 Network World 03 05 01 Where should traffic shaping occur Network World 03 07 01 WAN side traffic shaping Linux Kernel Traffic Control Shaping and QoS A Practical Guide to Linux Traffic Control Web based traffic shaping bridge router Dynamisches Bandbreitenmanagement im Chemnitzer StudentenNetz German work about DynShaper Software used at CSN student network at Chemnitz University of Technology Manuals Retrieved from https en wikipedia org w index php title Traffic shaping amp oldid 1079591890, wikipedia, wiki, book, books, library,
