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{{short description|IEEE task group active from 1995 to 1998}}
{{Short description|Network standards task group, 1995–1998}}
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'''IEEE P802.1p''' is the name of a task group active from 1995 to 1998 and responsible for adding traffic class expediting and dynamic [[multicast]] filtering to the [[IEEE 802.1D]] standard. Essentially, the task group provided a mechanism for implementing [[quality of service]] (QoS) at the [[media access control]] (MAC) level. Although this technique is commonly referred to as '''IEEE 802.1p''', the group's work with the new priority classes and [[Generic Attribute Registration Protocol]] (GARP) was not published separately but was incorporated<ref name="802.1p published in 802.1D-1998">{{cite web|title=IEEE 802.1|url=http://www.ieee802.org/1/|page=802.1p section}}</ref> into a major revision of the standard, IEEE 802.1D-1998,<ref>[http://standards.ieee.org/getieee802/download/802.1D-2004.pdf IEEE 802.1D-1998]</ref> which got later on incorporated<ref>{{cite web|title=802.1Q-2014 - Bridges and Bridged Networks|url=http://www.ieee802.org/1/pages/802.1Q-2014.html|publisher=IEEE}}</ref> into IEEE 802.1Q-2014 standard.<ref>[http://standards.ieee.org/getieee802/download/802-1Q-2014.pdf IEEE 802.1Q-2014]</ref> The work also required a short amendment extending the frame size of the Ethernet standard by four bytes which was published as '''IEEE 802.3ac''' in 1998.


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'''IEEE P802.1p''' was a task group active from 1995 to 1998, responsible for adding traffic class expediting and dynamic [[multicast]] filtering to the [[IEEE 802.1D]] standard. The task group developed a mechanism for implementing [[quality of service]] (QoS) at the [[media access control]] (MAC) level. Although this technique is commonly referred to as '''IEEE 802.1p''', the group's work with the new priority classes and [[Generic Attribute Registration Protocol]] (GARP) was not published separately but was incorporated<ref name="802.1p published in 802.1D-1998">{{cite web|title=IEEE 802.1|url=http://www.ieee802.org/1/|page=802.1p section}}{{fv|reason=Current version of page does not mention 802.1p. We could look for an archived version but that would still be [[WP:PRIMARY]].|date=June 2021}}</ref> into a major revision of the standard, IEEE 802.1D-1998,<ref>[https://web.archive.org/web/20051210051119/http://standards.ieee.org/getieee802/download/802.1D-2004.pdf IEEE 802.1D-1998]</ref> which subsequently was incorporated into IEEE 802.1Q-2014 standard.<ref>{{cite web|title=802.1Q-2014 - Bridges and Bridged Networks|url=http://www.ieee802.org/1/pages/802.1Q-2014.html|publisher=IEEE}}</ref> The work also required a short amendment extending the frame size of the Ethernet standard by four bytes which was published as '''IEEE 802.3ac''' in 1998.
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The QoS technique developed by the working group, also known as [[class of service]] (CoS), is a 3-[[bit]] field called the Priority Code Point (PCP) within an [[Ethernet frame]] header when using [[VLAN]] tagged frames as defined by [[IEEE 802.1Q]]. It specifies a priority value of between 0 and 7 inclusive that can be used by QoS disciplines to differentiate traffic.

⚫
The QoS technique developed by the working group, also known as [[class of service]] (CoS), is a 3-[[bit]] field called the Priority Code Point (PCP) within an [[Ethernet frame header]] when using [[VLAN]] tagged frames as defined by [[IEEE 802.1Q]]. It specifies a priority value of between 0 and 7 inclusive that can be used by QoS disciplines to differentiate traffic.


== Priority levels ==
== Priority levels ==
Eight different classes of service are available as expressed through the 3-bit PCP field in an [[IEEE 802.1Q]] header added to the frame. The way traffic is treated when assigned to any particular class is undefined and left to the implementation. The IEEE, however, has made some broad recommendations:<ref>{{Citation |title=IEEE Std 802.1Q-2014, Bridges and Bridged Networks |url=http://ieeexplore.ieee.org/servlet/opac?punumber=6991460 |format=PDF |at=Table I&#8209;2 - Traffic type acronyms}}</ref>
Eight different classes of service are available as expressed through the 3-bit PCP field in an [[IEEE 802.1Q]] header added to the frame. The way traffic is treated when assigned to any particular class is undefined and left to the implementation. The IEEE, however, has made some broad recommendations:<ref>{{Citation |title=IEEE Std 802.1Q-2014, Bridges and Bridged Networks |url=https://ieeexplore.ieee.org/document/6991462 |format=PDF |at=Table I-2 - Traffic type acronyms}}</ref>


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Note that the above recommendations have been in force since IEEE 802.1Q-2005 and were revised from the original recommendations in IEEE 802.1D-2004 to better accommodate [[Differentiated services|IP DiffServ]].
Note that the above recommendations have been in force since IEEE 802.1Q-2005 and were revised from the original recommendations in IEEE 802.1D-2004 to better accommodate [[differentiated services]] for [[IP network]]ing.


== See also ==
== See also ==
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== References ==
== References ==
{{reflist}}
{{reflist}}

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{{IEEE standards}}


==External links==
==External links==
* [http://standards.ieee.org/getieee802/download/802.1D-2004.pdf IEEE 802.1D-2004] (contains original 802.1p changes - now part of 802.1Q-2014)
* [https://web.archive.org/web/20051210051119/http://standards.ieee.org/getieee802/download/802.1D-2004.pdf IEEE 802.1D-2004] (contains original 802.1p changes - now part of 802.1Q-2014)
* [http://standards.ieee.org/getieee802/download/802-1Q-2014.pdf IEEE 802.1Q-2014] (incorporates 802.1D)
* [http://standards.ieee.org/getieee802/download/802-1Q-2014.pdf IEEE 802.1Q-2014]{{dead link|date=July 2024|bot=medic}}{{cbignore|bot=medic}} (incorporates 802.1D)

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{{IEEE standards}}


[[Category:Computer network technology]]
[[Category:Quality of service]]
[[Category:Quality of service]]
[[Category:IEEE 802|IEEE 802.1p]]
[[Category:IEEE 802|IEEE 802.1p]]

Revision as of 18:58, 27 August 2024

IEEE P802.1p was a task group active from 1995 to 1998, responsible for adding traffic class expediting and dynamic multicast filtering to the IEEE 802.1D standard. The task group developed a mechanism for implementing quality of service (QoS) at the media access control (MAC) level. Although this technique is commonly referred to as IEEE 802.1p, the group's work with the new priority classes and Generic Attribute Registration Protocol (GARP) was not published separately but was incorporated[1] into a major revision of the standard, IEEE 802.1D-1998,[2] which subsequently was incorporated into IEEE 802.1Q-2014 standard.[3] The work also required a short amendment extending the frame size of the Ethernet standard by four bytes which was published as IEEE 802.3ac in 1998.

The QoS technique developed by the working group, also known as class of service (CoS), is a 3-bit field called the Priority Code Point (PCP) within an Ethernet frame header when using VLAN tagged frames as defined by IEEE 802.1Q. It specifies a priority value of between 0 and 7 inclusive that can be used by QoS disciplines to differentiate traffic.

Priority levels

Eight different classes of service are available as expressed through the 3-bit PCP field in an IEEE 802.1Q header added to the frame. The way traffic is treated when assigned to any particular class is undefined and left to the implementation. The IEEE, however, has made some broad recommendations:[4]

PCP value Priority Acronym Traffic types
1 0 (lowest) BK Background
0 1 (default) BE Best effort
2 2 EE Excellent effort
3 3 CA Critical applications
4 4 VI Video, < 100 ms latency and jitter
5 5 VO Voice, < 10 ms latency and jitter
6 6 IC Internetwork control
7 7 (highest) NC Network control

Note that the above recommendations have been in force since IEEE 802.1Q-2005 and were revised from the original recommendations in IEEE 802.1D-2004 to better accommodate differentiated services for IP networking.

See also

References

  1. ^ "IEEE 802.1". p. 802.1p section.[failed verification]
  2. ^ IEEE 802.1D-1998
  3. ^ "802.1Q-2014 - Bridges and Bridged Networks". IEEE.
  4. ^ IEEE Std 802.1Q-2014, Bridges and Bridged Networks (PDF), Table I-2 - Traffic type acronyms
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