>> through to LACP-based load-balancing like agr(4),
> Please, does LACP (with agr or not) do also redundancy, or only
> increase throughput?

Honestly, I have no idea what LACP is for.  Presumably the standard
would say, but the IEEE demands payment to be allowed to look at their
standards (which actually makes me question whether we should want to
follow them, but that's an issue for a different day).

> That is, if two links are aggregated, and one fails, do all the
> frames go through the other, or is one half of them lost?

Everything I've seen indicates that the remaining link(s) pick(s) up
the load.  Whether this depends on LACP or not I couldn't say.

One of the most bothersome things about agr(4), to me, is that which
link a packet goes out seems to depend on nothing but a hash of
assorted data related to the packet.  This means that if links of
different speeds are aggregated, the slower one(s) will get overloaded.
I'd expect it to simply pick the interface with the shortest output
queue....

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