Ethernet has been around for a very long time (for technology that is) and has evolved to the monster it is today. There are millions of pages of information on the subject and hundreds of classes, certifications and degrees you can get. For our use of ethernet, however, we will just need to start with a very limited view. So first a little bit of history, you know for that bar wager with your friends, then we will get into it.
Back in the 1970’s Xerox started developing ethernet based on a government system in use at the time. It was introduced commercially in 1980 and then standardized in 1983 by the IEEE or Institute of Electrical and Electronics Engineers as IEEE 802.3. This first version was called 10BASE5 using a coax cable ring to connect computers in a building, later in 1990 the standard was updated to IEEE 802.3i which is how we see it today as 10BASE-T using twisted pair cabling. Since then several enhancements have been made both is speed and usability including, the addition of power over ethernet or POE (IEEE 802.3at-2009, my personal favorite).
That is the uber abridged history, now let’s see how we can use it to take over the world.
When we look at creating a production network, one of the first things to look at is the equipment needed to carry the data. For our needs, in the entertainment industry, there are three basic pieces of gear (one of them is hardly ever seen anymore), hubs, switches, and routers. They do basically the same job, connect ethernet devices together, but with varying levels of sophistication
nearly obsolete at this point with the price of better Ethernet equipment going down. Hubs usually have low port count (four or five generally) and function basically as data splitters, so data comes in on one port and is sent to all the other ports at the same time, with very little processing. This is ok for slow speed, noncritical applications but not for today’s much higher speeds and complex networks.
Ethernet switches are very “in” these days, a large amount of company’s make these, you can almost pick one up at 7eleven. There are a couple of manufacturers that provide specialized products for us in entertainment (yeah) Switches come in multiple port configurations from 4 to 32 ports or more and could be desktop or rackmount. For the most part, switches are also data splitters but they do this in a smarter way, data comes in on one port and is sent out to only the port that needs it. This allows for faster data rates and greater data integrity. It is capable of a bunch of other things and can even do some of the functions of a router too, but for now…
These are the big brains on the network, and do a lot of processing of data. These come in all sorts of configuration from a four port desktop model to 900-pound refrigerator-sized units. At the lowest level, routers move data between multiple networks or “route” data. This is why you have one in your house (probably), it is moving traffic between your internal network, your computers and iPads, and the external network of the ISP. Consumer routers, these days, combine other network processes together in the same unit like a firewall, a DHCP server, a modem a switch and WIFI access points, kind of the Swiss Army knife of networking.
Since the 1990’s we have been using twisted pair cable to transport ethernet short distances within buildings (100m or 328 ft). Today this cable has become a commodity, for the most part, because the specifications of it are an industry standard, category 5 cable or CAT5 defined in EIA-568-A. With a few exceptions, rugged construction being almost the only one, any brand of CAT5 will do the job. Depending on the situation, CAT5 cable is fairly cheap and available almost anywhere. There are several enhancements to twisted pair like CAT5E, CAT6, and CAT7, these are mainly for increased speeds.
CAT5 uses a standard RJ45 8 pin modular connector or 8P8C (8 pins 8 contacts). The 4 pairs of the cable or 8 individual wires connect to the 8 pins of the connector then they are crimped on with special tools. There are two specs for the order of the wires in the connector, 568A, and 568B, below there is a visual of the differences. To make a standard cable just pick one of the specs then make sure you use it on both ends of the cable. Building a network cable is a fairly easy and straightforward process, the tools and connectors are easily found and pretty cheap (you see why we like ethernet so much, cheap and easy to use).
The IP Address
Every piece of equipment on the network needs to have an address, like our post office example in other posts, if the mailman does not know where to send our letter, the letter will end up in the dead letter office. The address for the mailman on a network is called the IP address. In use most often today is IPv4 which looks like this 192.168.2.122, but since the world is running out of those addresses a new standard is being deployed, IPv6 which looks something like this 2001:cdba:0000:0000:0000:0000:3257:9652, a load more confusing so we will just focus only on IPv4.
The IP address can be assigned in two ways, statically and dynamically. Dynamic addressing is used most often, at your house when you connect your phone to your WIFI, the router will give it an IP address because it has joined the neighborhood and the mailman has a letter. You never have to set up your phone with and address, this job is handled by a DHCP (Dynamic Host Configuration Protocol) server, usually build into your router. This is great for everyday use but since we need to access things directly by their IP address this method is not ideal because the address could change. Static addresses are the solution, this is where we manually set up the device with an address, it will never change so we can depend on it (like an old friend).
There are several different scenarios for setting up IP addresses in various environments which we will discuss in other articles
Couple of Examples
Here are two examples of common, simple configurations of a network.
1) Computer, Switch, and Interface – Static address
2) Computer, Router, Switch, Printer and multiple interfaces – static and dynamic
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