How Stuff Works — Networking

Well, since this entire class is about networking, I sure did get a doozy of a first topic to try to read, understand, and explain. It’s far too dense to fully get into, but I’ll give an overview, some key terms (here’s a link to a handy glossary), and an analogy. Let’s start with this short (3:27) video I found that does a nice job with the general idea.  Apparently it’s also trying to sell Netgear routers and switches, but the advertising isn’t too annoying:  How Computer Networks Connect and Work 

Next, if you have 13:01, you’ll really understand what happens inside the network by watching this video: How Packets Travel in the Network (3d animation) Plus, you’ll get to see a network visualized as a sort of campy sci-fi movie, starring “Router” as a very close cousin of an Imperial Probe Droid from Star Wars and “Switch” as a cackling Pinball Wizard. Look for the Windows 3.1 screen shot with the Netscape Browser — a blast from the past! Seriously, the video really does a great job with making this make sense for people who aren’t computer scientists. It’s also a good laugh for some of the rhetorical choices they made. Engineers. 🙂

So, basically, a network consists of a MEDIUM (something that provides a path for the signals/information to travel, such as copper coaxial cable or fiber optic cable, which is preferred because it consists of a twisted pair of wires, one for sending, one for receiving), that is broken into SEGMENTS (also known as “collision domains”; a piece or instance of the medium) which contains one or more NODES or STATIONS, each with its own address. Information moving along the medium, is organized into FRAMES (like a sentence) which consist of PACKETS (like words). A network is governed by a PROTOCOL (rules for constructing the frames and organizing the information; TCP/IP is one protocol, Ethernet {or 802.3 IEEE} is another, token ring is a third). A network is subject to certain LIMITATIONS, such as the length of the cable, the number of devices, etc. SWITCHES connect nodes to a network segment and direct traffic to various nodes with it.  Using ALGORITHMS, a ROUTER acts as the boundary for a particular network, transferring information from one network to the next (or not, depending on the results of the algorithm). Routers talk to each other (using their own protocol), and can connect networks using different protocols (e.g. from ethernet to TCP/IP). Routers and switches (using their protocols) ensure that the information gets where it is intended and doesn’t have a COLLISION with other packets of information; routers attempt to LOAD BALANCE, much like packing a semi so that there is no wasted space and it doesn’t tip, a network is efficient when traffic moves smoothly, without a bottleneck or a single area working harder than another. The router constantly makes decisions in real-time to facilitate this balance. There exists the ability on any given network to send information from one node to only a single other node, or to send information from one node to ALL nodes (Broadcast). There are various ways to connect to a network, physically (via a cable — a WIRED network) or WIRELESSly (e.g. bluetooth) or a HYBRID, but even if the medium is not visible or known to each node or user, there exists a physicality to every network. You can have networks inside of another network (a LAN, inside a WAN, for example), and the INTER-Net is the connection of many networks that choose to be connected.

Once you’re on a network, you can do various things, such as share, and connect, and allow others to use your computer or your software applications (desktop sharing) or information. The concept of ownership and autonomy become problematized on a network. Someday soon, if Ubiquitous Networking is enacted, then any computer or device within range of you and your smartphone/PDA will become “yours” for as long as you need it. That paradigm shift may just break your brain. It won’t be YOUR brain or YOUR computer;  your autonomy and your hardware is part of the collective.

Phew. So here’s my analogy. See if this helps:

Imagine you are in a restaurant. This restaurant is a network of its own, defined by the boundaries of the restaurant. This restaurant network is part of a larger network of restaurants, but today, you are inside just this one. The floor of the restaurant is divided into sections, each one governed by a waiter (I’m using this word deliberately even though it is somewhat gendered, bc the word “server” is confusing in this context; however I intend the waiter to be gender neutral 🙂 who travels back and forth between each table and the kitchen. The waiter’s section is a network segment.  Inside each server’s section are individual tables, which we will call nodes. A node talks to a waiter, but not to other nodes (tables in the restaurant). The waiter is like the switch, s/he directs information from the nodes to a server (e.g. the kitchen, which serves up  packets, errr, plates, of food/information) and can talk to other waiters. The tables are connected through the waiters, but not directly to each other. The host/hostess is like the router, controlling who comes into the network (restaurant) and the flow of traffic to the various sections (network segments) and tables (nodes).  The host ensures that the guests are supposed to be there, are the right protocol (e.g. have a reservation, are wearing a shirt and shoes, or a tie as needed) and ensures that a single waiter (switch) isn’t given two or more tables in a row (overloading him/her) or causing a collision or logjam in the kitchen (at the server).  If everything runs smoothly, the correct food is made, on time, and delivered to the correct table, and all enjoy the food they ordered and have a positive experience with the network.

Does that help, any? Well, maybe it made you hungry.

So, your activity to help you think a bit about networking and the nested nature of them (networks inside of networks, connections between networks, communications across networks, the language of networks):

1. Go to https://ifttt.com/
2. Click Join IFTTT with whatever email and password suits you
3. Browse the explanations on the site. IFTTT allows you to create Protocols for how to connect your own networks, and what actions should be taken. In effect, it acts as a router between your networks, according to the commands you give it.
4. Create one or more “recipes” using the site’s graphical interface (for example, I created a recipe that sends me a text message every time a Job ad for an astronaut is posted on Craigslist in Charlottesville. No,  I don’t expect to get many texts. Think about which of your networks you might want to connect, when, how, and why. “Share” your recipe if you like.
5. Then go to this Google Doc and answer the quick reflection question about your experience with IFTTT and how it relates to networking. Identify yourself before you type and put your text in its own color in order to differentiate. Comment on other peoples’ answers using the comment feature.

References:

Razavi, Roozbeh.  “How Routing Algorithms Work”  19 November 2002.  HowStuffWorks.com. <http://computer.howstuffworks.com/routing-algorithm.htm>  18 January 2014.