In some respects they are all the same. Collocation simply means to co-locate your network equipment at another location. CLEC's (FD, XO, Megapath) collocate equipment all the time in a CO or POP from the ILEC (Bellsouth, Verizon, Quest). They are just collocating different gear but the end result is the same.
For that matter at one time MediaOne in Atlanta (long before they were gobbled up by AT&T then Comcast) allowed anyone to collocate equipment at certain hub sites. I don't know the details of how, what, where and why but I know it was done. Theoretically the same could be done at Bellsouth or similar if you know the right person, or are willing to pay the right amount, which may have been the case with MediaOne.
For Data Center vs collo, they are mostly one and the same. Let's put it this way, a collo facility is a data center but the reverse may or may not be true. The only difference between the two would come in play on the rules of the data center. Some data centers (take NAC, the site where DSLR is hosted) may not allow equipment to be collocated (I don't know if they do or not, it's just an example) but they will let you buy all the pre-existing dedicated servers you want and basically achieve the same thing. But assuming NAC does allow you to collo equipment does not mean they aren't a data center.
Basically a data center is any hardened (we hope) facility that houses various types of equipment for the purpose of allowing remote users access to it for any number of reasons or methods. A CO or POP could even be called data centers, in fact they are likely much more hardened than a typical data center. But just like a CO or POP can serve specialized needs a collo can as well. Basically what I mean by that is that a CO usually wouldn't host your server but will host your DSLAM if you were a CLEC, a collo on the same token will host your server but may not have any pre-existing dedicated servers to sell you.
As for how you obtain the bandwidth you need ..... that really depends on where you put your servers and that also means you may or may not be billed on 95th percentile as well. If you buy rack space from a carrier hotel such as 55/56 Marietta here in Atlanta you would be on 95th percentile because you are being plugged into the network infrastructure of the building. The advantage to that is there are dozens of companies that have end points in that building so say you wanted something from Georgia Tech's servers, just a couple of hops in the colo facility and you are on the gatech.edu network and you never even touched the public internet to get there.
But at the same time if you rent colo space from an ISP then you have the power and cooling advantages but you aren't plugged directly into their network. Instead what they did was sell you the T1 or DS3 or whatever and all you paid for was the port cost no loop costs because there really wasn't any loop (at least not in the sense of what is out on the poles).
Also there is a difference in how each company sells their space. Some places let you purchase rack space 1U at a time. Some lets you hosts tower based servers while some do not. Some force you to buy a portion (or all) of a rack (say 1/4 or 1/2 of a rack) but it will be dedicated to whatever you can stuff in there and it will usually be locked. XO on the other hand only sold cages. What you get is basically a small "room" where you bring in your own racks and populate then how ever you want. This is the best option usually for those that have existing racks and infrastructure and just want to have them in a data center.
Remember....collocation is not about staffing - it's about location of your equipment. Instead of running data circuits and enhanced power supplies to your location, you'll put your servers in a data center where they have lots of high speed circuits and robust environmental controls, and big power backup generators. They do have staff at those data centers, that sometimes will do things for you if contracted at extra cost.
The other side of Collo is bandwidth. If say you were a "bigger" company ..... the build out cost of running a DS3 or more to your location might be cost prohibitive. This is more directly the point if you need peering redundancies.
The biggest difference is if you "rent" bandwidth instead of your own pipe. Most bill on the 95%. Its not like an all you can eat DSL line or cable. You pay by the MB .... plus the rack space you use and power. The plus side, the world could end but more than likely your servers will be fine. COLO's are built like Fort Knox. If the world ended however no one is going to care that your servers are up.
If you need assistance in finding a collocation solution .... or any bandwidth solution for your network infrastructure needs .... you can get that help at no cost to you from DS3-Bandwidth.com.
Michael is the owner of FreedomFire Communications....including DS3-Bandwidth.com and Business-VoIP-Solution.com. Michael also authors Broadband Nation where you're always welcome to drop in and catch up on the latest BroadBand news, tips, insights, and ramblings for the masses.
Article Source: http://EzineArticles.com/?expert=Michael_Lemm