CIS512-Week 7 Assignment Part A - Critical Thinking

- Explain Subnet Mask?

Subnet mask is very easily understood if you think about a network of main highway Interstates (network ID), leading to local county roads (subnetwork ID), down to the road where your house sits (host ID). A subnet mask is a 32-bit value of "1" bits, or 255, for the network ID and subnetwork ID, and "0" bits for the host ID portion. Subnetting looks at the "1" bit or 255 route, and says, we are not looking at that value of the road directions but we are looking at the portion of the IP address that is masked with a "0" value. That "0" value is getting you down to street address fidelity after unmasking the IP address. Taking into account the subnet mask and netmask of an routing schema is like telling someone to drive a major Interstate Highway, possibly I-95, to another lesser known route, possibly Route 1, on down to your local Main Street. For example, use the following address; 63.34.12.42, that has a net mask of: 255.255.0.0, and a sub net of 255.255.255.0. Someone that lives in your local neighborhood would know that 63.34.12.42 will take you to a host ID of .42, or right to your neighborhood street. However if you are giving your distant cousin your address, and she lives in another part of the country you would have to give her more information. Your major Interstate would be the net ID of 63.34, your minor county road would be the subnet ID of .12, and your local street would be a host ID of .42. The sub net mask portion would tell the local neighbor you are right around the corner, and would tell your cousin in a remote area that they need to use the main network ID, subnetwork ID, and host ID to find you.

- Explain Class A, Class B, Class C IP Address?

Classes of IP addresses are like explaining big fancy iconic celebrities, local well-known "sort of celebrity" types, down to the average fella down the street. A Class A IP address is like saying, WOW, that is someone important. They are so important and big that they can purchase and use an entire Class A IP range, the Elvis and Marilyn Monroe's of the icon world. High level big shots, like the US Government or major Universities might be fancy enough to have a Class A range. Not many Class A types floating around anymore, truth be told. A Class B IP range is like saying we are sort of like hot shots, we have some importance but we don't need nearly the routing firepower of a Class A address, so we'll take up a comfortable second in the Class B range. Class B ranges might be used by smaller Internet Service Providers (ISP's) or possibly by mid-range business entities that can use so many addresses. Now lets talk about the rest of us normal folk, we likely live in the Class C range. It is not so bad down here in the Class C range. Class C out numbers the other classes of IP in a serious way, given that IP ranges can be further broken down by subnetting, NAT'ing (network address translation's), and by using a proxy. Class D address are reserved for broadcasting messages, like the local town news service, and Class E is reserved for research and development by the mad scientist down the street.

A specific break down as follows;
Class Range
A "Elvis type icons" 0.0.0.0 to 127.255.255.255
B "Local heroes" 128.0.0.0 to 191.255.255.255
C "Ma and Pa" 192.0.0.0 to 223.255.255.255
D "News service" 224.0.0.0 to 239.255.255.255
E "Spooky scientist down the street" 240.0.0.0 to 247.255.255.255

- Explain Classless vs. Classful Routing Protocols?

CIDR or Classless Inter-Domain Routing is something that was started in 1993 when the old IP routing protocol schema's designed in 1970 were determined to be too limiting. Basically the world wide web was running out of unique addresses to put on the outside wrapper of a package and the delivery guys (routers) that sent around the packages were getting very confused. Imagine of mailing addresses were limited to the same number combinations as IP addresses, and you could only send mail to people in your same state (same subnet). How would you ever send a delivery to your Grandma in Alaska?. You would only be able to have as many mailing addresses as possible number combinations in the following scheme; XXX.XXX.XXX.XXX. When taken at face value that is around 4.3 billion possible combinations, and that seemed nearly endless back in 1970. Now fast forward to today, when phones, printers, vending machines, and television services all require an IP and you will quickly see that 4.3 billion IP's might not be enough to route IP's around all the network devices on the entire planet, and those delivery guys would be really confused and frustrated. So what happens when you need to send a package or mail outside of your state? Do we just say too bad, you are out of luck, no mail for you. No sir, something had to be figured out and quickly. Classless routing is when subnet mask information is transmitted with the package to be delivered, basically telling the delivery man, this package is destined for another state. Or classful routing when you tell the delivery service, this bugger is staying right here in my good ol' state.

- Explain Link State vs. Distant Vector Routing Algorithm?

You are getting ready to go on a trip. First thing you need to decide is how to get there? Do you want to take a plane, train, boat, or automobile? Do you have ton's of time to get to your destination, or is your boss greedy and you can't get any time off work? Or do you need to get to the destination as cheaply as possible because you are poor and have no money, so your car is the only option. Is this a vacation or possibly a trip to attend a funeral in your hometown? Your start point is Philadelphia, PA, and your end point is Virginia Beach, VA. With a Link State routing algorithm you might travel from Philly to VA Beach in any manner of routes and transportation modes, but you want it to be FAST. You might hop on a boat (dial-up routing) and stop in Baltimore and Washington DC first to pick up a high-speed jet liner, then head on down to the beach. Or you might just want to go point to point, Distance Vector, and get in a private car in Philadelphia and drive directly to your final destination in VA Beach. Link state is like saying you really don't care how you get to the destination just get me there as quickly as possible, car/taxi on one side, jet in the middle, and shuttle service on the other side. Where as Distance Vector is like saying hey, I own a super efficient hybrid car that can't go over 65 mph, and I'm going to drive myself from Philly to VA beach on one tank of gas direct. Using no other modes of transportation. It might not be the fastest way, but it is as direct as possible and via one mode.

- Explain Bandwidth vs. Throughput?

My eyes are bigger then my stomach!! Perfect thing to describe bandwidth, and throughput. Bandwidth is described as the maximum rate that information (data) can be moved, where as throughput is how fast the information really moves. In this case, my eyes are ENORMOUS and I'm starving. I have just entered a hot-dog eating contest and I want to shove down as many hot-dogs as I can eat as quickly as I can get them in my hands and down my throat. I dream that my bandwidth is 100 hot dogs, and I'm so HUNGARY I can eat them ALL. However throughput will be my arch-nemesis, I have to chew these suckers, they have to go down my throat, which surely can't handle as many as my big hands can shove in my big mouth. Soon my jaws will get tired of chewing, my mouth will become dry, and things will not go down my throat so easily. Those hot-dogs will start to jam up mid-way down the long road to my stomach. Soon my stomach will start to fill up, and things will generally start to clog up. My big dreams of maximum input (those 100 hot dogs), will soon be governed by the physical structure of my body. My throughput in the end might only be 25 hot dogs, though I have 100 sitting in front of me, and my brain is still saying ... "Hey, I can eat those dogs, keep them coming!!". However your body is now straining, screaming at you, and possibly saying (physically via some gage reflexes), you are not stuffing anymore hot-dogs down this mouth, into this throat, and down to settle in this stomach.