> 1. why the heavy ul traffic ? i can understand the
> dl part, but not the heavy ul.
> 
> 2. although the dl is at 270kb/s, httrack only
> reports transfer rate at less than 10kib/s ? there

If it's an update, httrack has to send the request which is the  upload
trafic. If the item hasn't been updated, then nothing but the acknologment is
sent back so no download and no transfer rate.