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.
LANs that are larger than one. -use more than one switch-an organization with several floors would place a switch in each floor (and computers would then be connected to this switch w/ UTP cable) -switches on each floor connect to each other via faster-speed optical cable.