Re: [Qirg] Survey paper about the Quantum Internet Protocol Stack

[Alexandre Petrescu <[e-mail]>]

Le 13/06/2022 à 19:08, Joseph D Touch a écrit :
[...]

>> I would then say that IP needs electromagnetic waves (be them
>> through copper, fiber or through nothing, like WiFi) - in order to
>> transmit datagrams, otherwise IP would not work.
> 
> IP can use any boson or fermion; qubits can use any boson or fermion
> that can exhibit superposition.
> 
> E.g., I can run IP by sending notes by carrier pigeon (in the famous
> example); that does not use EM waves.

Fair enough.  There is an RFC for transmission of IP datagrams with
avian carriers (avian==pigeon).  There is also at least one
implementation visible on youtube.  That does not use electromagnetic waves.

IIRC the RFC with IP on avian carriers was an April's Fool.  It can be a
subject of joke.  However, the transmission of information with pigeons
can also be a serious matter.  This tool - sending information via avian
carriers - can be extremely useful under certain circumstances.

In that sense, it can be a serious matter to write an
IPv6-with-AvianCarriers I-D that takes into consideration an IPv6
address of the pigeon.  Sending a packet in that way: source -
intermediary - destination, each having an IP address, could be a novel
paradigm in the Internet, which is used to source-destination only.

Further, it can be considered that the data carried by a pigeon would be
encrypted, and if that used a quantum-resistant algorithm then we had an
approach between quantum networking and avian carriers.

>> I suspect the qubits dont need electromagnetic waves in order to
>> appear elsewhere (aka 'to be transmitted'), hence there is a
>> difference.
> 
> They do too. The collapse of entanglement of the superposition can
> happen later, BUT it also always relies on classical communication to
> be meaningful.

This is entirely unclear to me, I dont know(?)

I thought, really, that quantum communication did not involve
electromagnetic waves at all, but some other way of transmitting data.

Alex

> 
> I.e., collapsed entanglement that is not classically coordinated is
> useless; it's isomorphic to a spontaneous error.
> 
>> I would search which field in an IP header better expresses that
>> need of electromagnetic waves.  There is no field which tells that
>> it might need a certain power of these waves, or more Teslas than
>> Volts.
> 
> IP does use in-band labels for switching, but so does MPLS, Ethernet,
> etc. Qubits cannot because measuring them to use them for switching
> would collapse their state.
> 
>> But there is an enormous number of kinds of ways to transmit these 
>> eletromagnetic waves.  In this set, there are even more kinds of 
>> 'links'.  For example, for transmitting electromagnetic waves only 
>> through copper there are many Ethernet, USB and ATM kinds of links;
>> for 'wireless' too (transmit electromagnetic waves through nothing)
>> there are many kinds of 802.11 and 802.15.4 kinds of links.
>> 
>> There is a relationship that can be made between IP and the 
>> heterogeneity of the links carrying these electromagnetic waves.
>> IP exists only because there is heterogeneity of links.  If all
>> links were alike there would be no IP.
> 
> IP unifies a layer of message relaying above the link layer, not just
> above the physical layerEveryone could use the same Manchester
> encoded wires at the same speeds and one could run Ethernet and the
> other SONET. . Even if everyone in the world used 1G wired Ethernet,
> we'd still need IP to allow compartmentalization of the Ethernet
> subnet addresses.
>> 
>> The field 'Hop Limit' tells how far a packet could go, in terms of 
>> number of IP hops.
> 
> In IPv4, it's called a time-to-live for a reason. Routers that hold
> packets longer than 1 second are supposed to decrement the TTL
> accordingly, not just by 1.
> 
>> It is the number of intermediary hops - the different links - which
>> is decremented at each hop;
> 
> It is decremented for each IP router it passes through, not each link
> or different link. Packets from my laptop go through several Ethernet
> hops (one 802.11 WIFI, two wired Ethernet) but are not decremented at
> all until they get to an IP router.
> 
> In particular:
> 
>> if one sets that Hop Limit to 0, and tries to transmit it, it will
>> not go anywhere, because it would be 'dropped', like when grounding
>> a signal.
> 
> This is incorrect; it will go anywhere it can until it hits an IP
> router. If you don't believe me, try to ping your home router with a
> TTL of 0.
> 
>> In a quantum network, maybe one has to reset it like that (0) in
>> order to make it appear elsewhere (aka 'transmit' it).
> 
> I don't think that this makes sense; IP TTLs exist to prevent packets
> in the network from looping forever and thus clogging the network.
> Qubits don't have this problem.
> 
> Note that Ethernet packets don't have a TTL either, because their
> routing is prohibited from having loops.
> 
>> There might be other fields in IP headers that might be used as
>> help to illustrate that concept of IP needing electromagnetic waves
>> in classical Internet.  But the relationship of ND to an assumed
>> physical layer is probably less (hmm, maybe as much as)
>> appropriate.
> 
> ND correlates to the link layer, which is not the physical layer. It
> will reach everywhere a TTL 0 packet will reach.
> 
>> Of course, there would be a fundamental question of what the IP
>> address proper might mean when even a single bit of it might be a
>> qubit, actually.  When I manually assign an address to an
>> interface, that IP address is immuable: it is 1::1 forever.  But
>> with quantum addressing, this IP address is 1::1 'give or take'.
> 
> I don't think this equivalence has useful meaning. IP addresses are
> IP network endpoints. Qubits need physical endpoint identifiers too,
> which are equally immutable.
> 
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