-########## make sync PLCHOST=hostname
-########## make sync PLCHOST=hostname
-ifdef PLCHOST
-ifdef VSERVER
-PLCSSH:=root@$(PLCHOST):/vservers/$(VSERVER)
+########## sync
+# 2 forms are supported
+# (*) if your plc root context has direct ssh access:
+# make sync PLC=private.one-lab.org
+# (*) otherwise, entering through the root context
+# make sync PLCHOST=testbox1.inria.fr GUEST=vplc03.inria.fr
+
+PLCHOST ?= testplc.onelab.eu
+
+ifdef GUEST
+SSHURL:=root@$(PLCHOST):/vservers/$(GUEST)
+SSHCOMMAND:=ssh root@$(PLCHOST) vserver $(GUEST) exec