For reference, my libvirt managed virbr0 has forwarding delay 0. This is the default: http://libvirt.org/formatnetwork.html#elementsConnect I know that my VM is a leaf node (it only has one NIC and isn't going to create a loop in the network) and therefore it makes sense to eliminate the forwarding delay entirely. You might be interested in this link about STP delay on physical networks: http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00800b1500.shtml Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html