Re: [Qirg] Pull request for 'new challenges' subsection 'The first quantum networks may not be "routing and forwarding" networks.'

VAN DEN BOSSCHE Mathias <> Mon, 27 April 2020 14:34 UTC

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From: VAN DEN BOSSCHE Mathias <>
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Thread-Topic: [Qirg] Pull request for 'new challenges' subsection 'The first quantum networks may not be "routing and forwarding" networks.'
Date: Mon, 27 Apr 2020 14:34:25 +0000
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Subject: Re: [Qirg] Pull request for 'new challenges' subsection 'The first quantum networks may not be "routing and forwarding" networks.'
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Hi all,

Looking at the discussion on github, I am a bit puzzled at this idea of store-and-forward.  Actually, it deserves a motivation.
As we put it in the early generations, QIN establish an end-to-end entanglement link, and when it is ready, use it to send qbits directly end to end.
In a telephone network, it is like pulling a new copper or a new fiber anytime you want to make a call.

Later generations are proposed that tend to look more like classical networks (store-and-forward, i.e. routing, transport, etc).
It is clear that doing this will require progress in the nodes. But is it worth the pain? Of course in classical networks, pulling a new line is awfully costly.
Would it be so with entanglement ? Do we have to let us drive by analogy with classical networks? Aren’t there more options for
next generations (e.g. quantum broadcast with multipartite entanglement, etc)?

Just to get some light



De : Qirg [] De la part de Wojciech Kozlowski
Envoyé : lundi 27 avril 2020 14:20
À :
Cc :
Objet : Re: [Qirg] Pull request for 'new challenges' subsection 'The first quantum networks may not be "routing and forwarding" networks.'

Hi Shota,

Thanks for the update! I've just reviewed it:

Summary of my comments (follow the link for details):

I would like to spend some more time on the generation section though. I need to think more about what this section should contribute to the document. There is nothing wrong with what you wrote, I'd just rather not include it until I'm clear on what its contents should be and then I'll come back to your contribution.

However, the text about directionality, once you have a look at my proposed changes, can already be included. Since the generation section is currently in the same PR, if you would like your contributions merged sooner, please submit the section about generations as a separate PR, and I will merge the rest.



On Sat, 2020-04-18 at 08:35 +0900, Shota NAGAYAMA wrote:
Hi Wojtek,

I've updated the pull request.
I meant to clarify that routing would be the same, however, it might have been confusing. I have left out routing; just store-and-forward and store-and-swap are compared. And I added a section about generations. Please see other points on the pull request page and the document.

永山翔太 Shota Nagayama<><><><>

On Fri, Apr 3, 2020 at 6:32 PM Wojciech Kozlowski <<>> wrote:
Hi Shota,

Thanks for your contribution!

I've reviewed your update. My detailed review comments are on the GitHub repo:<>

In summary:

Overall, I think your contribution makes a very important point that will be very useful for people coming from a classical background. My comments are mostly about clarifying what you meant. With further clarifications, your contribution can be merged.

I am also not sure about this "routing and forwarding" and "routing and swapping" terminology. Is it common? I know of "store-and-forward" and perhaps we can say "store-and-swap" which highlights the need for memory (some proposals do not need a memory, not sure if they will be practical any time soon though). Also "store-and-swap" suggests we can keep things in memory for a long time which is not the case. I think this would be a good point to discuss. I would definitely suggest leaving routing completely out of this section as it is not actually discussed at all.


On Tue, 2020-03-31 at 14:02 +0900, Shota NAGAYAMA wrote:
Hi Wojtek,

How are things going? I'm looking forward to your review.

BTW, it's very nice that now you are a co-chair of the group :)

永山翔太 Shota Nagayama<><><><>

On Mon, Mar 9, 2020 at 5:53 PM Wojciech Kozlowski <<>> wrote:
Hi Shota,

Thanks for your contribution. I haven't had time to look at it yet so I won't include it in the draft I upload today. I will try to review it before Vancouver though so at least the work can still go on.


On Fri, 2020-03-06 at 01:51 +0900, Shota NAGAYAMA wrote:

I finally made a pull request for 'The first quantum networks may not be "routing and forwarding" networks.' subsection in the new challenges section. This subsection tells what is caused by the fact that Bell pairs are undirected network resources. Please find it.<>

永山翔太 Shota Nagayama<><><><>


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