



RTGWG                                                        Z. Han, Ed.
Internet-Draft                                                   R. Pang
Intended status: Informational                                     T. He
Expires: 1 January 2026                                     China Unicom
                                                            30 June 2025


 Terminology for Implementing Lossless Techniques in Wide Area Networks
                 draft-han-rtgwg-wan-lossless-terms-01

Abstract

   This document compiles a glossary of terminology commonly used in
   discussions about enhancing lossless transmission capabilities and
   network performance in Wide Area Networks, especially those terms
   already in related IETF drafts without further explanation.  To aid
   operators and implementers in reading contemporary drafts, this
   document attempts to provide an overview of terms and definitions for
   clarifying the current understanding, so as to facilitate the ongoing
   research.

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
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 1 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
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   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components



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   extracted from this document must include Revised BSD License text as
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   6
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   With the emerging of big data and intelligent computing, data-
   intensive applications such as high-performance computing (HPC),
   genetic sequencing, multimedia content production and distributed
   training, have growing demand for efficient and reliable network over
   thousands of kilometers during massive data transfers.  Implementing
   lossless techniques in Wide Area Networks is often associated with
   these scenarios that require high timeliness and reliability of data
   transmission, as well as network performance such as high throughput
   and extremely low packet loss rate.

   This document compiles a glossary of terminology commonly used in
   discussions about enhancing lossless transmission capabilities and
   network performance in Wide Area Networks, especially those terms
   already in related IETF drafts without further explanation.  The goal
   of this document is to provide an overview of terms and definitions
   for clarifying the current understanding, so as to facilitate the
   ongoing research.

   It is likely that the document will be refined in the future as
   understanding improves through increased insights and changes in
   practice.

2.  Terminology

   Lossless WAN: applies to scenarios that require high timeliness and
   reliability of data transmission across large geographical areas,
   providing on-demand,efficient and lossless data transmission across
   for user services.




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   Lossless Technique: The network technology that guarantees high
   throughput, extremely low packet loss rate, and low latency of the
   network through capabilities such as flow control, congestion
   notification, and flow scheduling, thus realizing lossless bearing of
   applications.

   PFC: Priority-based Flow Control.  It allows for selective pausing of
   traffic according to its class, enabling more granular flow control
   and preventing data loss due to congestion in data centers and other
   high-priority network environments [IEEE 802.1Qbb].  It is based on
   hop-by-hop, port-level feedback, pausing or resuming specific
   priority queues to prevent congestion.

   Fine-grained flow control: An enhanced PFC mechanism that enables
   precise flow control at flow/tenant or other granular levels, limits
   flow control to specified paths and slices, and provides intelligent
   congestion backpressure to prevent network congestion.

   ECN: Explicit Congestion Notification.  It is a mechanism that allows
   end nodes to be notified of congestion in the network without packet
   loss as described in [RFC3168].

   Rigid Bandwidth: The allocation of a fixed amount of network
   resources for specific traffic, ensuring a consistent and guaranteed
   level of service regardless of network congestion.  It can be zero,
   which means no bandwidth resource is reserved, but a forwarding
   resource object (eg,SQ/VOQ...) is still allocated to the user for
   flow control.

   Elastic bandwidth: The bandwidth is dynamically adjusted according to
   the network conditions to improve network bandwidth utilization and
   network transmission efficiency.  When the network is lightly loaded,
   users can fully utilize the available bandwidth resources to achieve
   peak traffic rates; when the network load is heavy, the bandwidth of
   user is limited.

   Network congestion: It occurs when the number of packets is too
   large, the network transmission performance deteriorates due to the
   limited resources of storage and forwarding nodes.  The congestion is
   usually determined by buffer occupancy at the output interface, which
   can in data loss, increased latency, decreased throughput, and even
   congestion collapse.









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   Buffer: It is used to store and forward packets, including single
   device buffer and multi-level network buffer.  The device buffer is
   shared and competed use by all ports.  When the buffer of single
   device is insufficient, multi-level network buffer can absorb burst
   traffic using buffers collectively across multiple network devices
   along the path.

   Packet loss rate: The ratio of the number of lost packets to the
   number of sent packets.  Lossless WAN needs to consider the influence
   of micro-burst and ensure extremely low or zero packet loss rate in a
   certain period of time.

   Throughput: The amount of data (measured in bits, bytes, packets,
   etc.) that a network, device, or port can successfully transmit per
   unit time.  The throughput of data transmission is affected by
   transmission distance, packet loss rate, effective data length and
   sending window size.

   BDP network: Bandwidth-Delay Product network.  It refers to a network
   in which the product of bandwidth and delay is significant,in a high
   BDP network, a large amount of data that can be in transit at any
   given time[I-D.liu-rtgwg-mdt-in-high-bdp].  BDP reflects the amount
   of data that can exist simultaneously on the transmission path in the
   network, which can help determine appropriate buffer sizes, flow
   control mechanisms, and congestion avoidance strategies to ensure
   efficient data transmission.

   Elephant flow: In computer networking, an elephant flow is an
   extremely large (in total bytes) continuous flow set up by a TCP (or
   other protocol) flow measured over a network link.

3.  Security Considerations

   This document does not have any specific security considerations.

4.  IANA Considerations

   This document does not have any IANA considerations.

5.  References

5.1.  Normative References

   [RFC3168]  Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
              of Explicit Congestion Notification (ECN) to IP",
              RFC 3168, DOI 10.17487/RFC3168, September 2001,
              <https://www.rfc-editor.org/rfc/rfc3168>.




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5.2.  Informative References

   [I-D.huang-rtgwg-wan-lossless-uc]
              Zhengxin, H., He, T., Huang, H., and T. Zhou, "Use Cases
              and Requirements for Implementing Lossless Techniques in
              Wide Area Networks", Work in Progress, Internet-Draft,
              draft-huang-rtgwg-wan-lossless-uc-01, 8 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-huang-rtgwg-
              wan-lossless-uc-01>.

   [I-D.he-huang-rtgwg-wan-lossless-framework]
              He, T., Huang, H., Zhengxin, H., Wang, N., and T. Zhou,
              "Framework for Implementing Lossless Techniques in Wide
              Area Networks", Work in Progress, Internet-Draft, draft-
              he-huang-rtgwg-wan-lossless-framework-00, 5 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-he-huang-
              rtgwg-wan-lossless-framework-00>.

   [I-D.liu-rtgwg-mdt-in-high-bdp]
              Ying, "Use Cases and Requirements of Massive Data
              Transmission(MDT) in High Bandwidth-delay Product (BDP)
              Network", Work in Progress, Internet-Draft, draft-liu-
              rtgwg-mdt-in-high-bdp-01, 5 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-liu-rtgwg-
              mdt-in-high-bdp-01>.

   [I-D.xiong-hpwan-uc-req-problem]
              Xiong, Q., Yao, K., Huang, C., Zhengxin, H., and J. Zhao,
              "Use Cases, Requirements and Problems for High Performance
              Wide Area Network", Work in Progress, Internet-Draft,
              draft-xiong-hpwan-uc-req-problem-00, 12 October 2024,
              <https://datatracker.ietf.org/doc/html/draft-xiong-hpwan-
              uc-req-problem-00>.

   [I-D.xiong-rtgwg-use-cases-hp-wan]
              Xiong, Q., Du, Z., He, T., Zhang, H., and J. Zhao, "Use
              Cases for High-performance Wide Area Network", Work in
              Progress, Internet-Draft, draft-xiong-rtgwg-use-cases-hp-
              wan-00, 3 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-xiong-rtgwg-
              use-cases-hp-wan-00>.










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   [I-D.xiong-rtgwg-requirements-hp-wan]
              Xiong, Q., Gao, C., Zhengxin, H., Zhao, G., and W. Qu,
              "Requirements for High-performance Wide Area Networks",
              Work in Progress, Internet-Draft, draft-xiong-rtgwg-
              requirements-hp-wan-00, 3 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-xiong-rtgwg-
              requirements-hp-wan-00>.

Acknowledgements

   TBD.

Contributors

   TBD.

Authors' Addresses

   Zhengxin Han (editor)
   China Unicom
   Beijing
   China
   Email: hanzx21@chinaunicom.cn


   Ran Pang
   China Unicom
   Beijing
   China
   Email: pangran@chinaunicom.cn


   Tao He
   China Unicom
   Beijing
   China
   Email: het21@chinaunicom.cn














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