Re: [Detnet] [Detnet ] Fwd: New draft on A Queuing Mechanism with Multiple Cyclic Buffers

Mohammadpour Ehsan <> Wed, 03 March 2021 08:31 UTC

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From: Mohammadpour Ehsan <>
To: Dangjuanna <>
CC: "" <>, "Liubingyang (Bryan)" <>
Thread-Topic: [Detnet] [Detnet ] Fwd: New draft on A Queuing Mechanism with Multiple Cyclic Buffers
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Subject: Re: [Detnet] [Detnet ] Fwd: New draft on A Queuing Mechanism with Multiple Cyclic Buffers
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Hello Joanna,

I think this is an interesting topic to be studied. The CQF with two buffers is addressed in IEEE802.1Q (annex T); however, it is not discussing multiple-queue version that leads to increase bandwidth utilisation when the dead time is large. From my understanding, this document covers CQF with multiple queues that is very nice. Regarding that, I have two questions:

1) Is the proposed mechanism operating in non-synchronised network?
2) Does the proposed mechanism allow different cycle times throughout a network? If so, how does the buffer allocation work (I didn’t get it well from the document)?



On 3 Mar 2021, at 08:01, Dangjuanna <<>> wrote:

Hi All,

Network forwarding with bounded latency and zero congestion loss is important for various industrial applications.  The DetNet working group draft "DetNet Bounded Latency"[draft-ietf-detnet-bounded-latency] describes requirements for queuing mechanisms.  To cope with long link delay, more than two cyclic buffers can be used.  Among the referenced queuing mechanisms, Cyclic Queuing and Forwarding (CQF) requires no per-flow dynamic state at core nodes, which is scalable when the number of flows grows.  This draft<> discusses the details of the cyclic queuing mechanisms. We propose a queuing model and mechanism with multiple cyclic buffers, which can improve bandwidth utilization without sacrificing latency and jitter.

I list a few points as follows for discussion.

1.       The mechanism with multiple cyclic buffers can be used for bounded latency guarantee.

2.       In actual deployment, we need to know which nodes have this mechanism. Therefore, both the controller and YANG model need to be extended.

3.       While the latency is guaranteed, network bandwidth utilization and long-distance deployment should be the key considerations.

I hope that those above issues will arouse our attention.



-----Original Message-----
From:<> []
Sent: 2021年2月22日 20:07
To: Liubingyang (Bryan) <<>>; Dangjuanna <<>>
Subject: New Version Notification for draft-dang-queuing-with-multiple-cyclic-buffers-00.txt

A new version of I-D, draft-dang-queuing-with-multiple-cyclic-buffers-00.txt
has been successfully submitted by Joanna Dang and posted to the IETF repository.

Name:               draft-dang-queuing-with-multiple-cyclic-buffers
Revision:  00
Title:                  A Queuing Mechanism with Multiple Cyclic Buffers
Document date:       2021-02-22
Group:               Individual Submission
Pages:               6

   This document presents a queuing mechanism with multiple cyclic

Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at<>g/>.

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