Ben K comment on FEC/RTX

[juberti]

Section 8

Because use of FEC always causes redundant data to be transmitted,
and the total amount of data must remain within any bandwidth limits
indicated by congestion control and the receiver, this will lead to
less bandwidth available for the primary encoding, even when the
redundant data is not being used. This is in contrast to methods
like RTX [RFC4588] or flexfec [I-D.ietf-payload-flexible-fec-scheme]
retransmissions, which only transmit redundant data when necessary,
at the cost of an extra roundtrip.

This seems to imply that "FEC" is a specific usage and that flexfec is
not
a subset of generic FEC. If so, this could probably be reworded to be
less confusing to the reader (though my suspicion is that the "always
causes redundant data to be transmitted" is only intended to apply to
specific mechanisms from Section 3).

flexfec is not quite a subset of generic FEC, since it also has a
retransmission format. Thoughts on how this could be reworded?

I think it would need to be "Because use of FEC in the form of
always causes [...]", but I'm not entirely sure what is. Is it
just "this document" or is there a broader framework or structure to which
this document adheres?

This document incorporates multiple FEC schemes, so there isn't another
overarching document (to my knowledge) that captures all of the mechanisms.

The intent here was to say "Because FEC, in general, always causes...", but
open to other phrasings.

Ah, I see now. I think what would help is "in contrast to methods like RTX
or flexfec (when retransmissions are used) [I-D.<...>]"