NETWORKING. What is a packet-switching network?

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1 NETWORKING What is a packet-switching network? The internet is an example of a packet-switching network! All internet traffic is broken down into packets, which are small chunks of data that are sent individually from point A to point B and reassembled at their destination. The first network to use packet-switching was called ARPANet, named after the government agency ARPA that invented the technology! Absolutely all internet communications use packets. What is encryption? How does it relate to a password? Encryption means your data has been put into secret code, or "locked" so that other people can't see it. You can encrypt specific files, an entire device, or your wifi packets! If you're using a wifi that has a password, you know encryption is running on that network and your actions can't be easily observed. A password is not the same thing as encryption: it is what allows the encryption to become unlocked (a password is like a key). What precautions should you take with Public Wifi? Why? It is O.K. to use public wifi! Really! However, your transmissions can be easily intercepted by anyone within range of that wifi network. So, purchasing things online (your name/address/payment info) or signing onto a password-based account (your username/password) may be things you want to avoid on an non-encrypted open network such as most public wifi hotspots. Is your IP Address a secret? What's one example of when it becomes known to someone? Your IP Address is what identifies you on the internet, so that you can send/receive packets. Since every single internet communication (including apps of course) uses packets, your IP Address is actually known to anyone/anything that you've communicated with! Every website you visit instantly knows your IP Address. Any message you send is tagged with your IP Address. Who can actually find you in real life if they know your IP Address? How? An IP Address can reveal your approximate location to anyone who looks it up. Someone can determine the county/state you live in with high accuracy, just by knowing your IP address. However, your IP address does not disclose your true identity or exact location. Since IP addresses are "loaned" when you connect to the Internet, your internet provider generally knows both who you are and what IP address you were assigned. Thus, law enforcement will often require internet providers (such as Comcast, Verizon, Sprint, etc) to match an IP address with a billing address if there is suspicion of a crime.

2 What two addresses are used to get packets to their destinations? How are they different? An IP Address is loaned to a device and used to send/receive packets across the internet. A MAC Address is built into a device and identifies it to equipment that is physically nearby. When you connect an ipad to a Wifi Router: they "see" each other's MAC Address first, then use that to work out a loan for an IP Address. What do "private browsing" or "incognito mode" actually do? What don't they do? From Google Chrome: Pages you view in incognito tabs won t stick around in your browser s history, cookie store, or search history after you ve closed all of your incognito tabs. Going incognito doesn t hide your browsing from your employer, your internet service provider, or the websites you visit. How can your internet traffic be protected from information thieves intercepting it? The word is encryption. If you're using an encrypted wifi network (one where you typed a password to connect) you can be reasonably sure people within range aren't intercepting your internet traffic. Additionally, some website have additional encryption built into them! How do people attempt to mask their true identities online? Does it work? Most internet activities leave a trail. Depending on if a crime is suspected and the severity of that crime, law enforcement might attempt to follow that trail of packets back to where they originated, and they often succeed. However, there are ways in which people attempt to obscure their identity online by forwarding all of their packets through a third-party. This is called a proxy-server and these services often claim to forward your packets and then delete the record of that transaction. It appears to others that the traffic originated from the proxy-server and not from you. It is the concept of using a "middle man" for your internet traffic. However, some proxies are actually setup by law enforcement just to catch people committing crimes!

3 Additionally, there is a service called TOR which uses multiple proxy-servers, hosted by community users and chosen at random for each communication, and with a different encryption put on for each leg of the journey! TOR is perhaps the most anonymous way to use the internet, but recent information has shown that it still might not keep you 100% anonymous. IMAGING What is resolution? Resolution is how many pixels there are in a picture or image, or how many pixels there are within a certain amount of space (like a square inch). High resolution will look clearer, low resolution can look grainy or pixelated. Why do people want high resolution for a camera or screen? High resolution images will appear sharper, and humans like a crisp image! It more closely resembles what we see in the real world around us. For a screen, resolution will affect how many pixels are shown. On a camera, resolution will affect how many pixels are captured. Photographs taken in extremely high resolution also allow the user to zoom into a small section of the image and still retain good quality. Is resolution the only measure of image quality? (Can something be high-res but poor quality?) There's a reason professional photographers don't shoot pictures with their phones! The more dots of color that are captured, the greater the resolution but you can have a lot of pixels and picture that is still blurry or out-of-focus! Professional grade cameras have better lenses for capturing and focusing light, before it is captured by the chip that turns it into digital pixels. In short, resolution isn't the only thing that matters. What are Megapixles and why are they used? A Megapixel is a measurement meaning about one million pixels. Instead of saying, "my iphone shoots eight million pixels per shot" you could say, "my iphone shoots in 8 megapixels." The more megapixels a device has, the higher the resolution. Why can resolution be measured with pixel dimensions (such as 1200 x 1000) or Dots Per Inch (such as 300DPI)? How does screen size relate to these two different ways of measuring?

4 One way to measure resolution is to count the total number of pixels in the image or video. This is how screen, image, or video resolutions are often measured. However, imagine you had a 70" TV and a 4" phone, and both of them had HD screens with the same number of pixels. Wouldn't the 4" phone be a lot sharper? The answer is YES! The pixels on the phone would have to be much smaller, since it has to fit the same number of pixels as the TV but into a smaller space. So another way to measure resolution is how many pixels fit into one square inch: dots per inch. Printer resolutions are always measured in DPI. What is a disadvantage to extremely high-resolution images or videos? The more resolution you have, the more storage space is needed. This is the greatest disadvantage! In a related matter, more processing power is needed to update more pixels, so in something like a video game a higher resolution requires a faster device! If you had a 4K UHD (Ultra High Def) screen, would everything you watched appear clearer? Every screen has a maximum number of pixels it can display at one time, but they can always show images that are of a lower resolution. With HD TVs, you can tune to channels that are not broadcast in HD, and you will see a lower resolution. With 4K TVs: when you tune to a regular HD channel, it will look exactly the same as it does on a HD TV. You will only see the 4K resolution when you tune to content actually broadcast in 4K (of which there is some, but not a ton yet).

5 STORAGE What is storage? Storage is what is sounds like: a way for storing data. There are many different types of storage devices, both built-in and removable! What is binary code? What data is stored in binary? Binary code are the 1's and 0's that all computer data is stored in. Pictures, sounds, video, text, apps, and everything else is encoded as a series of 1's and 0's to be stored or read! For example, the letter 'A' is stored in a computer as How do we measure storage? Why do we measure storage? We need to measure storage so that we can determine how much room is needed to save our files in various situations! We measure storage by grouping the bits (1's and 0's) together into larger units. Eight bits is one byte. From there the conversion goes: 1,024 Bytes = 1 Kilobyte 1,024 Kilobyes = 1 Megabyte 1,024 Megabytes = 1 Gigabyte 1,024 Gigabytes = 1 Terabyte How much storage is "enough" for a typical person in the year 2016? Explain your rationale. It depends on what you're saving! I think 500 Gigabytes or one Terabyte is generally plenty of storage for an individual. You could save millions of photos and songs on a terabyte. Of course, if you were downloading or recording 4K movies you might eventually fill up a Terabyte! Your answers can vary on this one, as this is an opinion question.

6 What is an advantage of Solid State Flash Storage? What is an advantage of traditional magnetic hard drives? Solid State Storage (Flash Storage) has no moving parts, thus giving is longer battery life and a lower failure rate due to physical impacts. It can also be faster in some situations! However, magnetic hard drive (the traditional kind with spinning discs inside) are cheaper per Gigabyte. For now. What is RAM (memory) used for? What does it mean if you have a little or a lot? RAM stores all of the open files/apps on your computer. The more you have, the more things you can have open at once. If you don't have a lot of RAM, your computer will hit a slow-down more often, and you won't be able to run more intensive applications. If a CPU has multiple cores, how does this affect speed? Each CPU Core is like a separate brain. The more cores a system has the more things it can think about at the same time. Most modern processors are 2-core or higher. In short, more cores means faster! How have processor speeds increased over the years? How does a device from the past compare today? Processors have roughly doubled in speed about every two years (just like Intel founder Gordon Moore predicted with Moore's Law). With this doubling effect: a processor from twenty years ago is literally 1,000 times slower than today's CPUs. What does a graphics/video card allow a system to do? A video card or graphics card is an optional piece of hardware that allows a device to handle more complex graphics. These cards have a graphics processor and graphics memory, which handle the graphics along with the device's primary processor and memory: team-work! Video game systems like Xbox have fantastic graphics cards. When you discard a device, which part of it should you consider keeping (or smashing)? Why? The only part of a device that has anything saved on it is the storage: either hard drive or solid state. Consider removing this from your device before getting rid of it, to eliminate the possibility of someone stealing your files from your discarded equipment.