Networks and the Internet generally rely on the asynchronous, software handshake protocols
described above but add a few more formalities to the process. Ethernet, for example,
has become a ubiquitous asynchronous network protocol widely used throughout
hospitals. The nature of a network, however, requires that many devices are able to share
the digital signal capacity of a single set of wires that run throughout a building. This minimizes
the cost of sending the signals throughout the building but requires that the devices
have a way to discern the messages that belong to it, and those it should ignore. To accomplish
this, a combination of hardware and software is required.
A great deal of specific detailed networking information is available in textbooks and
online sources like wwwcisco.com, so only a brief overview is provided here. At the software
level, one fundamental network design concept is that data are sent in finite length
packets of bits with a digital address for the recipient at the beginning of the packet.
Regardless of the network details, one basic networking rule is that all other devices
should ignore messages that are not addressed to them. However, this does not mean that
other devices cannot detect and read the messages, which creates significant security and
privacy challenges in the health care setting. Every computer on the network has an internal
network adapter card (Network Interface Card (NIC)) that handles the electrical
design and communication protocols (Network Access Method (NAM) for the network it
connects to. That card also has a unique ID number, known as the “MAC address”
(network Method Access Control).