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.
The network card in each machine must support the same protocols as the network router so that all devices are speaking the same language. A network adapter can substitute for an internal network card when a card is not present, or when the internal card does not support the required standard. There are two basic types of networks: wired and wireless. Network adapters are made for both types of networks, with more variety among the wireless flavor as there are different types of wireless networks. A network adapter made for a wired connection is a small USB dongle that features an Ethernet port. Ethernet cabling connects computers in wired networks, with the RJ45 Ethernet port resembling a standard RJ11 telephone jack on steroids.