How expansive "bzr update" for Emacs trunk?

[Oleksandr Gavenko]

  $ cat ~/devel/emacs/trunk/.bzr/branch/branch.conf
parent_location = http://bzr.savannah.gnu.org/r/emacs/trunk/
submit_branch = http://bzr.savannah.gnu.org/r/emacs/trunk/
bound_location = http://bzr.savannah.gnu.org/r/emacs/trunk/
bound = True

I mark that "bzr update" take about 1 MiB for
"Finding Revisions" and a lot MiB
(5.5 MiB between yesterday and today).

Is really bzr so dumb that require a lot of network traffic?
Or into Emacs sources go a lot of commit?

I restricted with 3G or GPRS Internet connection.
One time a month commit I get about 5 hours
(~7 KiB/sec download speed)!

Is bzr use plain (uncompressed) schema for
propagating changes?

So may be good switch to ssh protocol and set compression?

I also heir (but sorry if not correct) that bzr
developed for local network connection.
And for example if exist new changes it send
last 50 changeset even new only 1!

--
Best regards!