[Bloat] ECN issues

[Juliusz Chroboczek]

> The conventional wisdom certainly is that ECN should be left off simple 
> 1-RTT request-response protocols,

Just to avoid any misunderstandings:

   - Babel does not use ECN; the marking is due to Dave's local hack;

   - Babel is an asynchronous protocol that runs (mostly) over multicast,
     not a request-response protocol, so there's no obvious way to carry
     an echo bit in it;

   - Babel is designed to work well over extremely lossy links (with the
     standard implementation working reasonably well at 85% pre-ARQ loss).

[Shouldn't we be dropping people from the CC?]

-- Juliusz