ISO/IEC/IEEE 8802-1Q:2016/Amd 4:2017

Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 1Q: Bridges and bridged networks - Amendment 4: Frame preemption

Technologies de l'information — Télécommunications et échange d'information entre systèmes — Réseaux locaux et métropolitains — Exigences spécifiques — Partie 1Q: Ponts et réseaux pontés — Amendement 4: Préemption de trame

General Information

• Status: Withdrawn
• Publication Date: 28-Nov-2017
• Withdrawal Date: 28-Nov-2017
• ICS: 35.110 - Networking
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 21-Aug-2020
• Completion Date: 30-Oct-2025

Relations

• Amends: ISO/IEC/IEEE 8802-1Q:2016 - Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 1Q: Bridges and bridged networks
• Effective Date: 01-Jan-2022
• Revised: ISO/IEC/IEEE 8802-1Q:2020 - Telecommunications and exchange between information technology systems - Requirements for local and metropolitan area networks - Part 1Q: Bridges and bridged networks
• Effective Date: 23-Apr-2020

Standards Content (Sample)

INTERNATIONAL ISO/IEC/
STANDARD IEEE
8802-1Q
First edition
2016-03-15
AMENDMENT 4
2017-11
Information technology —
Telecommunications and information
exchange between systems — Local
and metropolitan area networks —
Specific requirements —
Part 1Q:
Bridges and bridged networks
AMENDMENT 4: Frame preemption
Technologies de l'information — Télécommunications et échange
d'information entre systèmes — Réseaux locaux et métropolitains —
Exigences spécifiques —
Partie 1Q: Ponts et réseaux pontés
AMENDEMENT 4: Préemption de trame
Reference number
ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
©
IEEE 2016
ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)

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Foreword
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© IEEE 2016 – All rights reserved iii

IEEE Std 802.1Qbu™-2016
(Amendment to
IEEE Std 802.1Q™-2014)
IEEE Standard for
Local and metropolitan area networks—
Bridges and Bridged Networks—
Amendment 26: Frame Preemption
Sponsor
LAN/MAN Standards Committee
of the
IEEE Computer Society
Approved 30 June 2016
IEEE-SA Standards Board
ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
Abstract: Enhancements to the forwarding process that support frame preemption are provided in
this amendment to IEEE Std 802.1Q-2014.
Keywords: Bridged Local Area Networks, IEEE 802.1Q™, LANs, local area networks, MAC
Bridges, metropolitan area networks, preemption, Virtual Bridged Local Area Networks, virtual
LANs
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PDF: ISBN 978-1-5044-2257-4 STD21074
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© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
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ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
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ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
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ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
Participants
At the time this standard was completed, the IEEE 802.1 working group had the following membership:
Glenn Parsons, Chair
John Messenger, Vice-Chair
Michael Johas Teener, Chair, Time Sensitive Networking Task Group
Tony Jeffree, Editor
Christian Boiger Stephan Kehrer Jessy Rouyer
Marcel Kiessling
Paul Bottorff Panagiotis Saltsidis
David Chen Philippe Klein Michael Seaman
Feng Chen Jouni Korhonen Daniel Sexton
Weiying Cheng Yizhou Li Johannes Specht
Rodney Cummings Christophe Mangin Wilfried Steiner
Janos Farkas Tom McBeath Patricia Thaler
Norman Finn James McIntosh David Thornburg
Geoffrey Garner Hiroki Nakano Jeremy Touve
Eric Gray Bob Noseworthy Paul Unbehagen
Craig Gunther Donald R. Pannell Karl Weber
Stephen Haddock Walter Pienciak Brian Weis
Karen Randall Jordon Woods
Mark Hantel
Marc Holness Maximilian Riegel Helge Zinner
Hal Keen Dan Romascanu Juan Carlos Zuniga
The following members of the individual balloting committee voted on this standard. Balloters may have
voted for approval, disapproval, or abstention.
Michael Johas Teener
Thomas Alexander Dan Romascanu
Adri Jovin
Butch Anton Jessy Rouyer
Shinkyo Kaku Larry Samberg
Lee Armstrong
Stefan Aust Piotr Karocki Bartien Sayogo
Christian Boiger Stuart Kerry Michael Seaman
Nancy Bravin Yongbum Kim David Solomon
William Byrd Robert Landman Kevin Stanton
Juan Carreon Mark Laubach Thomas Starai
Rodney Cummings David Lewis Eugene Stoudenmire
Janos Farkas Arthur H. Light Walter Struppler
Yukihiro Fujimoto William Lumpkins Michael Swearingen
David Gregson Michael Lynch Patricia Thaler
Randall Groves Elvis Maculuba Mark-Rene Uchida
Stephen Haddock Arthur Marris Lorenzo Vangelista
Marek Hajduczenia Jonathon Mclendon Dmitri Varsanofiev
Jerome Henry Richard Mellitz George Vlantis
Khurram Waheed
Marco Hernandez Charles Moorwood
Guido Hiertz Michael Newman Stephen Webb
Werner Hoelzl Nick S.A. Nikjoo Karl Weber
C. Huntley Satoshi Obara Hung-Yu Wei
Noriyuki Ikeuchi Alon Regev Natalie Wienckowski
Atsushi Ito Robert Robinson Oren Yuen
Tony Jeffree Benjamin Rolfe Zhen Zhou
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
When the IEEE-SA Standards Board approved this standard on 30 June 2016, it had the following
membership:
Jean-Philippe Faure, Chair
Ted Burse, Vice-Chair
John D. Kulick, Past Chair
Konstantinos Karachalios, Secretary
Chuck Adams
Ronald W. Hotchkiss Mehmet Ulema
Masayuki Ariyoshi Michael Janezic Yingli Wen
Stephen Dukes Joseph L. Koepfinger* Howard Wolfman
Don Wright
Jianbin Fan Hung Ling
J. Travis Griffith Kevin Lu Yu Yuan
Annette D. Reilly Daidi Zhong
Gary Hoffman
Gary Robinson
*Member Emeritus
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
Introduction
This introduction is not part of IEEE Std 802.1Qbu-2016, IEEE Standard for Local and metropolitan area networks—
Media Access Control (MAC) Bridges and Virtual Bridged Local Area Networks—Amendment 26: Frame Preemption.
This amendment to IEEE Std 802.1Q-2014 provides enhancements to the forwarding process that support
frame preemption.
This standard contains state-of-the-art material. The area covered by this standard is undergoing evolution.
Revisions are anticipated within the next few years to clarify existing material, to correct possible errors, and
to incorporate new related material. Information on the current revision state of this and other IEEE 802
standards may be obtained from
Secretary, IEEE-SA Standards Board
445 Hoes Lane
Piscataway, NJ 08854
USA
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
Contents
2. Normative references. 13
3. Definitions . 14
4. Abbreviations. 15
5. Conformance. 16
5.4 VLAN Bridge component requirements. 16
5.13 MAC Bridge component requirements. 16
5.26 End station requirements—enhancements for frame preemption. 16
6. Support of the MAC Service . 17
6.7 Support of the Internal Sublayer Service by specific MAC procedures. 17
8. Principles of bridge operation. 18
8.6 The Forwarding Process . 18
12. Bridge management . 20
12.30 Managed objects for frame preemption . 20
17. Management Information Base (MIB) . 22
17.2 Structure of the MIB . 22
17.3 Relationship to other MIBs. 22
17.4 Security considerations . 23
17.7 MIB modules . 23
Annex A (normative) PICS proforma—Bridge implementations . 43
A.5 Major capabilities . 43
A.14 Bridge management . 43
A.24 Management Information Base (MIB) . 43
A.44 Frame preemption . 44
Annex B (normative) PICS proforma—End station implementations . 45
B.5 Major capabilities . 45
B.15 Scheduled traffic . 45
Annex Q (informative) Preemption and IEEE Std 802.1AE MAC Security. 46
Annex R (informative) Preemption and scheduled traffic. 48
R.1 Scheduling used in isolation . 48
R.2 Preemption used in isolation. 48
R.3 Scheduling and preemption used in combination, no HOLD/RELEASE . 49
R.4 Scheduling and preemption used in combination, with HOLD/RELEASE . 49
R.5 Bandwidth allocation and express traffic. 50
Annex S (informative) Bibliography . 51
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
Tables
Table 8-6 Gate operations . 19
Table 12-29 Frame Preemption Parameter Ttable . 20
Table 17-29 IEEE8021-Preemption-MIB Structure and relationship to this standard . 22
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
IEEE Standard for
Local and metropolitan area networks—
Bridges and Bridged Networks—
Amendment 26: Frame Preemption
(This amendment is based on IEEE Std 802.1Q™-2014 as amended by IEEE Std 802.1Qbv-2015.)
NOTE—The editing instructions contained in this amendment define how to merge the material contained here into the
base document and its other amendments to form the new comprehensive standard.
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instructions, change markings, and this NOTE will not be carried over into future editions because the changes will be
incorporated into the base standard.
IMPORTANT NOTICE: IEEE Standards documents are not intended to ensure safety, health, or environmental pro-
tection, or ensure against interference with or from other devices or networks. Implementers of IEEE Standards doc-
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This IEEE document is made available for use subject to important notices and legal disclaimers. These notices and
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Notes in text, tables, and figures are given for information only, and do not contain requirements needed to implement the standard.
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
2. Normative references
Insert the following reference in the appropriate collating sequence:
TM
IEEE Std 802.3br , IEEE Approved Draft Standard for Ethernet—Amendment 5: Specification and
Management Parameters for Interspersing Express Traffic.
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
3. Definitions
Insert the following definition in the appropriate collating sequence and renumber
appropriately:
3.x preemption: The suspension of the transmission of a preemptable frame to allow one or more express
frames to be transmitted before transmission of the preemptable frame is resumed.
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
4. Abbreviations
Insert the following definitions in the appropriate collating sequence and renumber
appropriately:
eMAC express Media Access Control
pMAC preemptable Media Access Control
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
5. Conformance
5.4 VLAN Bridge component requirements
5.4.1 VLAN Bridge component options
Insert the following list item at the end of the list, relettering as necessary:
ae) Support frame preemption as specified in 6.7.1, 6.7.2, and 8.6.8.
5.13 MAC Bridge component requirements
5.13.1 MAC Bridge component options
Insert the following list item at the end of the list, relettering as necessary:
n) Support frame preemption as specified in 6.7.1, 6.7.2, and 8.6.8.
Insert the following new subclause at the end of Clause 5, renumbering as necessary:
5.26 End station requirements—enhancements for frame preemption
An end station implementation that conforms to the provisions of this standard for frame preemption shall
a) Support the provisions of 6.7.1, 6.7.2, and 8.6.8.
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
6. Support of the MAC Service
6.7 Support of the Internal Sublayer Service by specific MAC procedures
6.7.1 Support of the Internal Sublayer Service by IEEE Std 802.3 (Ethernet)
Change the first paragraph of 6.7.1 as follows:
In addition to the provisions of 12.1.1 of IEEE Std 802.1AC-2012, an M_CONTROL.request primitive is
mapped to an IEEE 802.3 MA_CONTROL.request primitive having the same parameters. If the MAC
supports IEEE 802.3br Interspersing Express Traffic, then PFC M_CONTROL.requests are mapped onto
the MAC control interface associated with the express MAC (eMAC). An IEEE 802.3
MA_CONTROL.indication primitive is mapped to an M_CONTROL.indication primitive having the same
parameters.
Insert new text at the end of 6.7.1 as follows:
If frame preemption (6.7.2) is supported on a Port, then the IEEE 802.3 MAC provides the following two
MAC service interfaces (99.4 of IEEE Std 802.3br):
a) A preemptable MAC (pMAC) service interface, and
b) An express MAC (eMAC) service interface.
For priority values that are identified in the frame preemption status table (6.7.2) as preemptable, frames that
are selected for transmission shall be transmitted using the pMAC service instance, and for priority values
that are identified in the frame preemption status table as express, frames that are selected for transmission
shall be transmitted using the eMAC service instance.
In all other respects, the Port behaves as if it is supported by a single MAC service interface. In particular, all
frames received by the Port are treated as if they were received on a single MAC service interface regardless
of whether they were received on the eMAC service interface or the pMAC service interface, except with
respect to frame preemption.
If the value of the holdRequest managed object (12.30.1.5) transitions from FALSE to TRUE, a
MM_CTL.request(hold_req) primitive is issued to the underlying IEEE 802.3 MAC, with a hold_req
parameter value of HOLD, as described in Clause 99 of IEEE Std 802.3br. If the value of the holdRequest
managed object (12.30.1.5) transitions from TRUE to FALSE, a MM_CTL.request(hold_req) primitive is
issued to the underlying IEEE 802.3 MAC, with a hold_req parameter value of RELEASE.
NOTE—This additional material will be moved to IEEE Std 802.1AC in a future revision.
Insert new subclause 6.7.2 as follows:
6.7.2 Frame preemption
If the Port supports frame preemption, then a value of frame preemption status is assigned to each value of
priority via a frame preemption status table. The possible values of frame preemption status are express or
preemptable.
The frame preemption status table can be changed by management as described in 12.30.1.1. The default
value of frame preemption status is express for all priority values.
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
8. Principles of bridge operation
8.6 The Forwarding Process
8.6.8 Transmission selection
Insert the following immediately after NOTE 2:
In a port of a Bridge or station that supports frame preemption, a frame of priority n is not available for
transmission if that priority is identified in the frame preemption status table (6.7.2) as preemptable and
either the holdRequest object (12.30.1.5) is set to the value hold, or the transmission of a prior preemptable
frame has yet to complete because it has been interrupted to allow the transmission of an express frame.
8.6.8.2 Credit-based shaper algorithm
Change the text of list items e) and f), and insert new NOTEs, renumbering subsequent NOTEs,
as follows:
e) transmit. Takes the value TRUE for the duration of a frame transmission from the queue; FALSE
when any frame transmission from the queue has completed. If the credit-based shaper algorithm is
used in combination with frame preemption (6.7.2), transmit only takes the value TRUE while the
frame is actually being transmitted by the MAC. If the frame transmission is delayed or interrupted
(e.g., the frame is a preemptable frame and its transmission is interrupted to allow the transmission
of an express frame from a different queue, or the frame is an express frame and there is a delay
before transmission can start because a preemptable frame was being transmitted) transmit takes the
value FALSE until transmission of the frame commences or is resumed. Transmit also takes the
value FALSE during the transmission of any overhead that is a consequence of frame preemption;
i.e., any additional frame overhead that is added to the preemptable frame when preemption occurs.
NOTE 1—The consequence of this is that any overhead associated with preemption does not come out of the reserved
bandwidth for the credit-based shaper.
f) credit. The transmission credit, in bits, that is currently available to the queue. If, at any time, there
are no frames in the queue, and the transmit parameter is FALSE, and the transmission gate for the
queue is open (8.6.8.4), and credit is positive, and there is no preemptable frame from this queue for
which transmission is in progress but has been interrupted, then credit is set to zero.
NOTE 2—The condition that the transmit parameter is FALSE and a preemptable frame or part-frame is waiting in the
MAC for transmission can only occur if the credit-based shaper algorithm is used in combination with Preemption.
8.6.8.4 Enhancements for scheduled traffic
Change the second paragraph of 8.6.8.4 as follows:
A gate control list associated with each Port contains an ordered list of gate operations. Each gate operation
changes the transmission gate state for the gate associated with each of the Port’s traffic class queues and
allows associated control operations to be scheduled. In an implementation that does not support
enhancements for scheduled traffic, all gates are assumed to be permanently in the open state. Table 8-6
identifies the gate operation types, their parameters, and the actions that result from their execution. The
state machines that control the execution of the gate control list, along with their variables and procedures,
are specified in 8.6.9.
The base text of 8.6.8.4 is to be found in IEEE Std 802.1Qbv-2016.
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
Insert two new rows at the end of Table 8-6 as follows:
Table 8-6—Gate operations
Operation name Parameter(s) Action
Set-And-Hold-MAC GateState, TimeInterval Performs all of the actions defined for the SetGateStates
operation; in addition, the start of this operation marks
the point in the sequence of gate operations at which the
MAC associated with the port is to have stopped trans-
mitting preemptable frames. This is achieved by setting
the holdRequest managed object to the value hold (1), at
holdAdvance (Table 12-29) nanoseconds in advance of
this point for the hold to have taken effect at this point. If
frame preemption is not supported or not enabled (pre-
emptionActive is FALSE), this operation behaves the
same as SetGateStates.
Set-And-Release-MAC GateState, TimeInterval Performs all of the actions defined for the SetGateStates
operation; in addition, the start of this operation marks
the point in the sequence of gate operations at which the
MAC associated with the port is permitted to resume
transmitting preemptable frames; if an express frame is
currently being transmitted by the MAC, the release
takes effect at the end of that transmission. This is
achieved by setting the holdRequest managed object to
the value release (2), at releaseAdvance (Table 12-29)
nanoseconds in advance of this point for the release to
have taken effect at this point. If frame preemption is
not supported or not enabled (preemptionActive is
FALSE), this operation behaves the same as SetGateS-
tates.
The SetGateStates operation is defined in IEEE Std 802.1Qbv-2016.
The releaseAdvance parameter allows the timing of when the release command is issued to vary depending upon the
constraints of a particular implementation. Its value should be less than the minimum frame size so that release does
not occur too early and interfere with transmission of the last express frame.
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
12. Bridge management
Insert new subclause 12.30 and its subclauses and tables, as follows, renumbering as necessary:
12.30 Managed objects for frame preemption
The Bridge enhancements for support of frame preemption are defined in 8.6.8, 8.6.8.4, and 6.7.2. The
objects that comprise this managed resource are as follows:
a) Frame Preemption Parameter Table (12.30.1)
12.30.1 Frame Preemption Parameter table
There is one Frame Preemption Parameter table per Port of a Bridge component or end station. Each table
row contains a set of parameters that supports the enhancements for frame preemption (6.7.2), as detailed in
Table 12-29. Rows in the table can be created or removed dynamically in implementations that support
dynamic configuration of ports and components.
Table 12-29—Frame Preemption Parameter table
Operations
b
Name Data type Conformance References
a
supported
framePreemp- sequence of framePreemptionAd- RW BE 6.7.2,
tionStatusTable minStatus values 12.30.1.1,
12.30.1.1.1.
holdAdvance Integer, nanoseconds R BE Table 8-6,
12.30.1.2
releaseAdvance Integer, nanoseconds R BE Table 8-6,
12.30.1.3
preemptionActive Boolean R BE 12.30.1.4
holdRequest Interger {hold (1), release (2)} R BE Table 8-6,
12.30.1.5
a
R = Read only access; RW = Read/Write access
b
B = Required for Bridge or Bridge component support of enhancements for frame preemption.
E = Required for end station support of enhancements for frame preemption.
12.30.1.1 framePreemptionStatusTable structure and data types
The framePreemptionStatusTable (6.7.2) consists of 8 framePreemptionAdminStatus values (12.30.1.1.1),
one per priority.
12.30.1.1.1 framePreemptionAdminStatus
This parameter is the administrative value of the preemption status for the priority. It takes value express if
frames queued for the priority are to be transmitted using the express service for the Port, or preemptable if
frames queued for the priority are to be transmitted using the preemptable service for the Port and
preemption is enabled for the Port.
© IEEE 2016 – All rights reserved

ISO/IEC/IEEE 8802-1Q:2016/Amd.4:2017(E)
IEEE Std 802.1Qbu-2016
IEEE Standard for Local and Metropolitan Area Networks—Bridges and Bridged Networks—
Amendment 26: Frame Preemption
Priorities that all map to the same traffic class should be constrained to use the same value of preemption
status.
12.30.1.2 holdAdvance object
The holdAdvance object contains an integer value representing the maximum number of nanoseconds that
can elapse between issuing a HOLD (12.30.1.5) to the MAC and the MAC cea
...