-xend-config.sxp: isolate patch
-files/etc/xen/scripts/vif-sipbroute: isolate patch
-files/etc/xen/scripts/vif-sipbroute: gateway, interface (for arpspoof)
+sysvms/*: MAC addresses
+vif-sipbroute: isolate patch
+vif-sipbroute: gateway, interface (for arpspoof)