I’ve decided to launch yet-another new series here on the blog of whall called “Learning is Fun!”  I figure if you have a decent story behind something, anything can be learned.  It might be technical, inspirational, or whatever.

So I wanted to combine some internet drama with learning something technical.  Follow along, will you? 

One facet of my immense geekdom is the ability to remember TLA’s - Three Letter Acronyms.  And I’m talking about USEFUL technical acronyms, not today’s vernacular, although that does remind me of a good joke I read over at Ajooja’s site.

A blonde texted her boyfriend with “What does idk” mean?
He responded “I don’t know.”
“OMG!” she texted back “No one does!”

(no actual blondes were harmed in the telling of this joke). 

My memory has a special ability to hold onto these technical acronyms.  I know PING is Packet INternet Gopher. I know CSMA-CD is Carrier Sense Multiple Access Collision Detection.  I’m anal that way - I *want* to know what makes up the acronym, and why.  I think it helps me understand the underlying technology better. 

That CSMA-CD thing I mentioned before?  That has to do with ethernet.  Networking.  Hubs, switches, 802.3, blahblah blah.  You probably don’t care how the electronic signals get from your computer to whall.org; you. just. care. that. they. do.

When you plug in an ethernet cable to a hub, everything on that hub is like a party line (remember party lines?)  Every port “hears” everything said to every other port.  If you plug four PC’s into a hub, it’s literally like four people are on a party line (Multiple Access). 

Let’s get into the drama.

If person A (Joan) wants to talk to person B (Jane), first Joan has to listen so as not to talk over anyone else.  Because oh by the way, only one person can talk at a time on ethernet.  So Joan sits and waits (Carrier Sense) until there’s a break in the conversation.  When she senses the opening, she blurts out “JANE!!! ARE YOU OUT THERE? IF SO, WHERE YOU AT, BEYOTCH!?!?” (this is known as ARP). 

Remember, EVERYONE is listening to the party line.  They all agreed ahead of time that they would only respond if asked except in special circumstances, so Person C (Bob) and Person D (Tom) hear the request but ignore it.  Just like they did at TequilaCon, but this time they did it sober, which is inexcusable.

So Jane hears the request and responds “I’M RIGHT HERE IN FRONT OF YOU, MORON, AND HERE’S MY EXTENSION“.  This extension that she gives out is her MAC (media access control) address.  Now Jane writes down the extension and for the rest of that specific conversation, Jane prefaces her words with Jane’s extension.

If you’re following along, you might be thinking to yourself “wow, that is so fascinating.  But what happens with Collision Detection??!?”

Well, here’s the deal.  Even though everyone is polite enough to wait for a break in the conversation to start talking, somewhere in between the nanosecond it takes for them to hear the silence, the nanosecond it takes to start speaking, and the ohnosecond it takes for that electrical signal to start going down the cable, there’s always a chance that there will be a “jinx, you owe me a Coke” moment.  Jane and Joan might both be waiting to speak, they BOTH decide “now’s my chance!” and they BOTH start talking _at_the_same_time_. 

In real life, this usually isn’t a big deal for friends.  Some people can have a completely two-way conversation and both sides speak and listen and comprehend at the same time.  Others, when you attempt this, get mad.  For some reason, they think you’re not listening.  I think that’s what they said; I’m not sure.

But computers?  Electricity sent from one end of the cable hitting electricity coming from the OTHER end of the cable actually is NOT something that’s tolerated by the Ethernet Gods.  There is a physical collision - an explosion of sorts - that happens inside the cable.  A little “pop!” and everybody’s like “WHOAAAAA did you hear dat!?!?!” and then everyone gets in on the action and says “ooooooooh, don’t go there...”

They detect the collision and they decide to back off of talking for some random amount of time before they start listening again.  This is equivalent to “oh I’m sorry I talked over you - you go first” but in a more robotic, unfeeling and really lame way.  It’s kind of like stopping blogging but not permanently. 

But we have a small recipe for drama.  Because in normal ethernet world, Bob and Tom can hear everything Joan and Jane are saying!  So if they wanted to (like with a packet sniffer such as wireshark), they could listen, write down all the bad stuff, collude (not collide) and then backstab Joan and Jane.

Enter the “switch”

You may have heard about hubs and switches right?  Do you know the difference?  Well, a hub is the above description - a complete party line.  A switch, however, adds the concept of direct-dialing-by-extension.  The part about asking for an extension still happens (this is known as a broadcast), but when Jane starts dishing the trash talk about Bob’s shortcomings in the romance department, as long as she’s prefacing her conversation with Joan’s MAC address, the switch conveniently keeps their conversation just between the two people, and Bob is completely oblivious!

side note: Tom, however, is a switch administrator and secretly mirrored Jane and Joan’s ports to his own so that he could still spy on their talks, and wrote down everything about Bob.  He plans on blogging it later, because it’s been a few days since the Internet imploded and besides, blogdrama makes for a good comment run, and who cares if someone gets pushed out or leaves the blogosphere - there will be at least a dozen new bloggers to replace them!

So Joan and Jane can continue their gossiping, what they’re going to do about their hair, and OMG did you see the Bachelor!

side note: Tom learns that Bob is engaged to Joan, but cried out Jane’s name in the bedroom this one time.  This is especially awkward because Joan and Jane are sisters.  And in watching the conversations between Bob and Jane, he finds out that Bob’s been telling Jane that he plans on leaving Joan and marrying her instead, but he’s been stringing her along for months and in the meantime, Bob gets a little sumfin sumfin from them both.  Also, Bob’s email to one of his buddies exposes his ultimate plan, which is to sleep with both of them together

Bob meanwhile is over off to himself, doing lots of instant messaging, emailing, blogging, commenting and generally staying away from actual work and he finds that hours go by and he hasn’t done a thing that could be considered productive.  He thinks about going to Alaska.

side note: Tom decides that it’s in the best interest of everyone involved, and would save a lot of heartache not to mention further awkwardness if he were to insert himself into the situation and help calm it down.  So he plans to blackmail Bob with this new information so he can rent an upscale condo on the beach for a week.  He will invite both Jane and Joan to the condo, show them the proof, tell the story, and then they will be mad at each other, then sob, then cry and will need a strong male to comfort them and hey, did you notice my new nice condo?  Have you seen the bedroom?

Switches are cool.  Switches help prevent drama (they cut down on collisions).