In standard computer networking there are two different addresses associated with each host on the network; they are termed logical and physical addresses. The physical hardware address is a 48-bit , 12-digit number that is burned into the memory of each network interface card, and it works on the data link layer of the OSI model. An example of this “hexadecimal” number is 02-C3-7E-3D-0A-B4. This MAC address is unchangeable and unique to each system, and assigned to each device by the manufacturer. In addition, if you move a device to another network this address stays the same, as long as the network card has not been changed (Addressing Facts, n.d.). The MAC address is used mostly for identifying and sending information to hosts that are on the same network, or Ethernet. If you need to connect to a device on a network outside of your home or business ...view middle of the document...
When you travel to somebody’s house that you have never been to, or even are visiting out-of-town family, you need to know the city, state, and street number address to find the house and plan your route. This is similar to using the logical address of a device/host to route to an outside network and then finding the device on a different network. After you find that house (host) on another network (city, town, neighborhood, etc.), you will not need the logical address to find it again (Press, 2000). Your system will remember the route used to get there and use the physical address going forward.
Two logical addresses are used for any device:
1) The logical network address- this is called a subnet, and is the same for all devices on that same network segment. There are five different classes of the default subnet mask. An example of the subnet mask address could be 255.255.255.0, which is a Class C address.
2) The logical host address- this identifies a specific host on the network and each device needs a unique host address (Addressing Facts, n.d.).
In the TCP/IP network protocol, the IP address that is assigned to each device on a network contains both the host and network addresses. An IP address example could be 192.168.18.9. This is a Class C address, the network address is 192.168.18.0 and the host address is 9 (Addressing Facts, n.d.).
Another very effective way to picture how addresses work is, again, from Barry Press: “Logical addresses let the message travel to the destination LAN; physical addresses (derived from the logical address) get the message onto the destination computer; and port addresses get the message to the right software.” (Press, 2000).
Press, B., and Press, M. (2000). Physical and Logical Addresses. Retrieved from an excerpt of the book “Networking by Example” on http://www.informit.com/articles/article.aspx?p=20012.
Addressing Facts. (2014). Retrieved April 27, 2015 from http://content.testout.com/client/labsimanywhere.html?mincachedate=04-30-2015-23-00.