"There are several significant changes in LTSP 5 which
make the system much more usable. You will get enhanced security as
now the GUI is exported using ssh -X and not the old XDMCP. SSH
offers encryption of course which is actually faster and safer. The
remote connection is made with LDM a python application that
connects using SSH and not the old KDM or GDM. NFS has been dropped
and replaced with NBD. NBD or Network Block Device is a network
block device which emulates a block device like a hard drive over
the network. This allows you to either use this space as swap or
use it as network diskspace."