Firstly, install the utility "axel" by :
cd /usr/ports/ftp/axel ;make install clean
Next, tell ports to use the external utility to perform downloading task. Insert the following lines into /etc/make.conf :
FETCH_CMD=axel FETCH_BEFORE_ARGS= -n 4 -a DISABLE_SIZE=yes
The parameter "-n 4" is to tell "axel" break the file into 4 parts and download simultaneously; "-a" is to show an alternate download progress bar. Do take note that, DO NOT set the simultaneously connection ("-n") too many as it takes time for the server to tear down the connection after the downloads terminate. This could block other people from downloading it. After all, these software are the "Best" & "Freely" available to everyone.