The influenza vaccine is unusual in that most years a different vaccine is made. Because strains of influenza virus that circulate in the community can differ from one season to the next, the vaccine must change to best protect against those different strains.
In VMware, switches are used to establish a connection between the virtual network and the physical network. With ESX and ESXi, two different kinds of switches can be used: standard switches and distributed switches.
How network works - Network switches and broadcast packets. Network switches - A network switch is an Ethernet device that can divided an Ethernet network up in different zones. Within one zone all computers will se each others traffic but outside the zone only traffic that is aimed for computer in that zone is transferred.