Packet routing in quantum networks

Q&A

Jessica Illiano: Are the classical header separated from the quantum
payload? If yes, how does the coupling between the the header and its
payload takes place? How do you manage a payload or a classical header
loss?

Stephen: Depends on multiplexing scheme: time or wavelength. In both
cases use classical data header. Want to investigate this further, not
clear what's the best way. Coupling is some optical scheme and/or
multiplexing. Payload/header loss: depends on the protocol. If header is
lost, not much you can do - must drop the payload. If the payload is
lost, if the application allows for it, you ask for retransmission
(doable with generic states like QKD).

Patrick Gelard: Isn't QEC a challenge for your approach ? Indeed it is
necessary to transmit on the same virtual circuit the quibt with its
redundant qbits to apply the error correction

Stephen: Same challenges as third generation quantum repeaters.

Roland Bless: It seems that you implicitly consider hop-by-hop routing
decisions for packet-switching, however other schemes may be possible,
e.g., source routing or label switching. Do you consider the latter
out-of-scope?

Stephen: We're not restricting. Not out-of-scope.

RdV: At WQRN in Chicago, a participant was adamant that the quantum
channel will have to be at 1310 otherwise the cross-talk won't be
manageable.

Stephen: We need to experiment, we consider future hardware.

Bruno: Experimental results data muxing classical and quantum on the
same fiber for QKD: https://arxiv.org/abs/2112.14254. Using Cisco
multiplexers. 1310 for quantum, 1550 for classical. Standard fiber.