Re: [LOOPS] Packet sequence numbers

[Carsten Bormann <[e-mail]>]

> Even though I originally suggested the QUIC method of continuously increasing sequence numbers, I think this assessment of the trade-offs is very good, and now I tend to agree that, for LOOPS, repeating sequence numbers would be better.

I think that this conclusion is a good basis for continuing the work.
I made the necessary changes (I think) in https://github.com/loops-wg/gen-info/commit/2dd7634

I also added some text about mitigating ACK ambiguity, which is facilitated if the ingress never sets “ACK desired” on a retransmission.

There is currently no detailed text on how to decide to retransmit.  The current spec is mute (a.k.a. “flexible”) on the implementation strategy.  For hole-based retransmission triggering, re-using the PSD needs to include a hold-off for packets that have recently been retransmitted so another copy of block 2 information that just confirms the existing hole doesn’t trigger another retransmission.  For a time-based retransmission scheme (as in RACK), retransmission would simply move forward the packet into the then appropriate slot.

> +1 on the need for more-than-once, for wireless links.

Right.  I think that single retransmission is a nice implementation strategy for some applications, so we should continue to pay attention that we don’t inadvertently make it harder to do than it is now.

Grüße, Carsten