> If i wanted to avoid adding the new field t_extra, won't the
> following  work too ? 

Um.  I'm still thinking about it.  I am not sure that it is the
same...  And, I am thinking of other's comments.

> Also, is there a simple way to count the number of times the
> 'Limited Transmit' code helped avoid a retransmit timeout ? That
> is, helped a fast retransmit to occur when otherwise it would have
> resulted in a retransmit timeout ?

As a heuristic, fast retransmit when cwnd is less than four packets
would qualify.  Hmm...  Due to my current state of mind I can't come
up with a concrete algorithm, but I would guess that you could
cleverly count ACKs and figure it out.  Why?  Are you thinking of a
counter or something?

Thanks,
allman