There are many types of data/packet routing or retransmission hardware and devices that networks can use for security purposes. Some use one or a combination of these for data transfer. However, each presents a level or type of vulnerability, additional unwanted threats, and countless types of risk. The ultimate design is to provide a means to control the flow of packet transfer. The main function of a switch, router, gateway or hub is the ability to process and forward data packets over the network. The creation and function is to ensure that each has its own unique functions and configurations that make one a more viable optional choice than the next to ensure data forwarding. For example, large networks will need routing protocols that will send the data packet to its intended destination and not transmit it across the entire network. Gateways provide nodes with a contactless connection to resources available to users. The basic gateways installed in many PCs are called NICs or network interface cards (Andrews, 2006, pp. 846-847). These gateways can be hardware or protocols within the particular installed equipment. It is essential that the data has the ability to traverse the network. However, to perform this function, data must be accepted/rejected and/or forwarded or deleted. In order to connect nodes, networks and interaction, gateways must be present. Without some form of gateway implementation, communications would be non-existent. However, the term gateway can also be referred to as routers, AP wiles, switches, and hubs. This is quite easy to distinguish as it indicates some form of access to network resources. The hubs are the base... middle of the card... there, however, with more precision involved. Nodes connected to the switch will not retransmit data to everyone. The switch will deliver its payload based on the listening destination, blocking everyone else from receiving the data. Essentially speaking and highly dependent on your network setup and configurations, each provides a single access point, entry/exit management, and some level of security. Works Cited (2006). Installing a network interface card. In J. Andrews, PC Management and Maintenance (pp. 846-847). Boston, MA: Technology Cengage Learning Course.Beasley, J. (2004). The mains switch. In J. Beasley, Network (pp. 92-93). Upper Saddle River, NJ: Prentice Hall.Institute, C. L. (2005). Switching and routing. In R. H. Ivy, Networking + Foundations and Certification (pp. 192-193). Upper Saddle River, NJ: Prentice Hall.