



quic                                                         X. Gao, Ed.
Internet-Draft                                               M. Han, Ed.
Intended status: Informational                              Z. Ruan, Ed.
Expires: 23 January 2026                                    China Unicom
                                                                  H. Shi
                                                                  Huawei
                                                            22 July 2025


               QUIC bandwidth awareness Acknowledgements
                   draft-gao-quic-network-awareness-ack-01

Abstract

   This document defines a quic ACK frame format for notifying path
   available bandwidth.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on 23 January 2026.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
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   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.




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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
   3.  Overview of ACK mechanism . . . . . . . . . . . . . . . . . .   3
   4.  Perception process of path available bandwidth  . . . . . . .   4
   5.  Path available bandwidth awareness ACK frame  . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   In the actual operation of intelligent computing services, high
   bandwidth demand scenarios are commonly present, while data
   transmission faces significant challenges in terms of efficiency and
   stability.

   Scenario 1：With the development of AI technology, some large-scale AI
   projects require computing resources from multiple data centers to
   participate in training together.  For example, data centers in
   different cities may have different types of data or computing power
   advantages, and in order to fully utilize these resources, data needs
   to be transmitted and shared between multiple data centers.

   Scenario 2：In order to balance flexible expansion of computing power
   scale and reduce cost investment, enterprises will distribute storage
   and computing resources in different geographical locations.  For
   example, placing storage resources in areas with lower costs, while
   deploying computing resources near user or business needs.  In this
   case, the transmission of data between storage and computing nodes
   becomes crucial.

   These scenarios all have a common feature, which is long data
   transmission distance and large data volume.  Therefore, it is
   necessary to fully utilize network bandwidth resources and improve
   data transmission efficiency.

   Certain nodes on the forwarding path may experience traffic
   congestion when the network traffic is high.  The actual maximum
   forwarding traffic of this path will become smaller than expected.
   Once this situation occurs,The sender needs to adjust the sending
   strategy based on the available resources of the current path to
   avoid packet loss due to exceeding the bandwidth.

   The perception of available path bandwidth is an important part of
   reducing network congestion and ensuring network reliability.  The
   sender perceives changes in the network environment and status in



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   real time, adjusts the speed in a timely manner, and achieves rapid
   response.The Quic protocol relies on feedback information provided by
   the ACK mechanism to achieve congestion control and reliable
   transmission functions.  This document is based on an extension of
   the quic ACK mechanism, which supports carrying the available
   bandwidth of the path and quickly notifies the sender of this
   indicator.  It is used to directly perform rate control and other
   operations on the sender, making data transmission more efficient and
   network resource utilization higher, greatly improving network
   service quality.

2.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Overview of ACK mechanism

   The triggering condition of ACK determines the timing of ACK
   generation and transmission.  The confirmation mechanism of the quic
   protocol generally involves the receiver immediately replying to an
   ACK message after receiving a specified number of data packets, or
   waiting for a specified time delay to reply to an ACK message
   regardless of whether a data packet has arrived.  [RFC9000] specifies
   a simple delay ACK mechanism, where the receiver can send an ACK
   every other packet, or send an ACK when the max_ck_delay timer
   expires.

   This document extends the quic ACK mechanism and adds conditions for
   triggering ACK: when the message received by the receiver carries
   information about the available bandwidth of the path, an ACK message
   is generated and sent to the sender, and the ACK message contains the
   specific value of the available bandwidth of the path, which is used
   by the sender to adjust the data transmission strategy.The specific
   value of the available bandwidth of the path in the ACK message is
   obtained from the available bandwidth information of the path in the
   message received by the receiver.











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4.  Perception process of path available bandwidth

 +-------+  pkt +--------+ pkt+tlm +--------+ pkt+tlm +--------+
 |  Data | ---->| network| ------> |network | ------> |  Data  |
 | Sender| ==== | device |  ====   | device |  ====   |receiver|
 +-------+      +--------+         +--------+         +--------+ 
      /|\                                                 |
       |                                                  |
       +--------------------------------------------------+
                         Notification Packets/ACKs

   The data packet is transmitted between the sender and the receiver,
   and the network device on the transmission path adds the detected
   available bandwidth information of the path to the data packet
   originating from the sender.  Specifically, network devices detect
   network status information based on device configuration information.
   Device configuration information is used to indicate the collection
   of network status parameters, or network status information is
   detected through network status collection instructions in business
   packets.  Network status collection instructions are used to indicate
   the collection of network status parameters.

   The available bandwidth information of the path is detected by the
   network device and added to the network layer header.  After
   receiving the message, the receiver peels off the network layer
   header, obtains network status information, and forms the specific
   value of the available bandwidth of the path, which is added to the
   transport layer quic ACK message.

   When the sender receives an ACK message from the receiver and adjusts
   the data transmission strategy, based on the specific value of the
   available bandwidth of the path, the data transmission rate of the
   data packet is increased or decreased.

5.  Path available bandwidth awareness ACK frame

   The extended ACK frame format also includes: 
  1)The type field represents the that contains path available bandwidth
  2)The specific value of available bandwidth for the path

   Network awareness ACK Frame {
  Type (i) = 0x20, 
  Largest Acknowledged (i),
  ACK Delay (i),
  ACK Range Count (i), 
  First ACK Range (i), 
  ACK Range (..) …,
  Path available bandwidth（..）, 
  }

   *  Type: type=0x20，Indicates that ACK carries path available
      bandwidth.






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   *  Largest Acknowledged ：A variable-length integer representing the
      largest packet number the peer is acknowledging.  This is usually
      the largest packet number that the peer has received prior to
      generating the ACK frame，Unlike the packet number in the QUIC long
      or short header, the value in an ACK frame is not truncated.

   *  ACK Delay: It represents the time it takes for the receiver to
      receive a message and for the receiver to send the ACK Frame.

   *  ACK Range Count:A variable-length integer specifying the number of
      ACK Range fields in the frame.

   *  First ACK Range: A variable-length integer indicating the number
      of contiguous packets preceding the Largest Acknowledged that are
      being acknowledged.  That is, the smallest packet acknowledged in
      the range is determined by subtracting the First ACK Range value
      from the Largest Acknowledged field.

   *  ACK Range:Contains additional ranges of packets that are
      alternately not acknowledged (Gap) and acknowledged (ACK Range).

   *  Path available bandwidth：The maximum data transmission rate that a
      path can provide for subsequent data transmission.

6.  Security Considerations

   TBD

7.  IANA Considerations

   The following frame types have requested to be provisionally added to
   the "QUIC Frame Types" registry under the "QUIC Protocol" heading.  +
+--------------+-----------------------------+---------------------+ 
|    value     |         Frame Name          |   specification     | 
+--------------+-----------------------------+---------------------+
|    0x20      |  path available bandwidth   |     section5        |
+--------------+-----------------------------+---------------------+ 
                Table1: Addition to QUIC Frame Types Entries

   When this document is approved, IANA is requested to change the
   registration to a permanent allocation of these frame types with the
   values described above.

Authors' Addresses







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   Xing Gao (editor)
   China Unicom
   Beijing
   China
   Email: gaox60@chinaunicom.cn


   Mengyao Han (editor)
   China Unicom
   Beijing
   China
   Email: hanmy12@chinaunicom.cn


   Zheng Ruan (editor)
   China Unicom
   Beijing
   China
   Email: ruanz6@chinaunicom.cn


   Hang Shi
   Huawei
   Beijing
   China
   Email: shihang9@huawei.com

























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