What limitations be placed on bzr if paramiko is not used?

[Ghee Teo]

Hi,

I have been reading and playing with bzr (the version in RHEL).
The documentation said that paramiko providing sftp support for bzr.
Is that the only functionality that it provides?
Can bzr utilize openssh for ssh operations ?

Thanks,

-Ghee
P.S. If would be good if you can reply to me directly since I am not 
subscribed to the alias.