Distilling complex networking and I.T. methodologies into easily to understand metaphors and stories.
Peering:
So you want to learn about peering? Jumping in to discuss peering and all of the inherent advantages is a difficult conversation to start. It’s like discussing with your oldest son about all of the ins and outs of prom, when he hasn’t picked out the girl quite yet….and that’s because he’s still in first grade and girls think boys are yucky. In order to get a good view of the peering concept you first need to look at Layer 3 Transit from a thirty thousand foot level.
Okay then, so what is layer 3 transit. Well, back in the day it would start with a dialer, followed by some crazy noises, then finally the familiar AOL voice saying “You’ve Got Mail”. Back in the day it was exactly that. You via a phone line reaching out to an online service and dialing directly in to them to explore the content that they had to over at a blinding 33kbps. These days, layer 3 transit is what takes you from your network to someone else’s network. No more do you search for a phone number of the service that you are trying to connect to, but rather simply using a familiar name that translates into less than familiar Internet Protocol or IP address.
Want to unravel the mystery of all of those fancy yet seemingly worthless or potentially obnoxious numbers? Here’s the skinny. When your computer wants to reach out and connect to another online service, it first takes the name of the service that it’s trying to connect to and translates the name into one of these IP addresses using a protocol called DNS which is essentially white pages for IP addresses. Once it has its destination IP, it does a calculation to determine if the destination is on our local network or not. Perhaps the destination is your printer, or a file server, or maybe your Apple TV to stream music to. If it’s local…the networking hard work is over. But, I would guess at some point you are going to want to try to connect to Google to check your Gmail or connect to iTunes to listen to some songs as you get yourself to work. Unless you work at Apple or Google, it’s highly doubtful that any of that traffic is “local”. In that instance, your computer passes the networking traffic to an upstream router which looks at the destination IP and matches up to it’s routing table to determine which way to send it. Your upstream sends it to another upstream, which sends to another. Your packets bounce around all over through routers of any number of providers, affectionately called “hops” until the calculations are completed and your request makes it to your final destination.
Why does it do all this? Well…feasibility for one. It’s wouldn’t be easy to subscribe to every online service that you wanted to connect to with a separate connection method. Another reason is resiliency. All of these paths are dynamically built and calculated. Ever been driving in your car and you aren’t able to turn down a particular street. Before you able to bust an illegal U-Turn, your friendly GPS has already recalculated the route around the road closure. Resiliency and redundant path calculations performed by ISPs are kind of like GPS for internet traffic. So, for example if a link or a router along the way of your normal path through cyberspace goes down, internet service providers will automagically recalculate another path around the effected system or link.
This all sounds great, but what’s the catch? Well…for one, with your traffic going through any number of different networks using paths that are dynamically calculated, it’s not overly secure. And, it’s slow. Slow?? I barely touch the like button on my friend’s Facebook post and they already have a notification. In many cases this is true, but if you have one connection to the internet and everyone is on Facebook, or YouTube at the same time, it won’t take long for that link to get congested or saturated. Remember that car analogy that we discussed earlier? Think about how long it would take for you to get work if there were no cars on the road. Now think about how long that would take during the typical morning rat race.. If you, like many of us, have to travel a highway to get to work you might need to allow some extra time to get there when everyone else is going to work as well. Yes…there is even traffic on the information superhighway.
So, the answer is just buy more bandwidth right? Well, not quite. First off, business quality bandwidth is expensive. It just isn’t always a fiscally sound decision to keep adding more and more bandwidth. Even if you did, it still might not really help. Let me explain. I have a full gigabit connection to the internet from my local internet provider to my house. And, I would think that many many other houses in my neighborhood have the same or similar. But yet, the internet still has a tendency to get slow when all the kids get home from school and start streaming Netflix or Amazon Prime video. And that is because internet service providers oversubscribe the bandwidth that they sell. The theory is, not everyone will be using all of their subscribed bandwidth all at the same time. So, even if we had 100 houses in the neighborhood, all with a full gigabit connection, there may only be 10 gigabit to the neighborhood. And again, since you traversing different ISPs over links that also can become congested, the speed of your connection is only as fast as the slowest link in a series of hops.
We’ve asked a whole bunch of questions, but we haven’t really come up with many answers. These days so many organizations have pushed critical services to the cloud. Office 365 handles our mail. Teams and WebEx keep us connected virtually with both voice and video. Inventory databases are hosted by Amazon. Files are hosted on Google Docs, and shared via Dropbox. How do we insure that our most critical business operations not only stay up, but stay more secure, and are available at the click without the nervous waiting? The answer is peering.
We said that ISPs link to one another in order to create that resilient world wide web? They connect to eachother at Internet Exchanges (or IX). While at one time they were reserved for only service providers, content providers started buying into them and connecting to other networks in them as well. Why would a content provider want to be in an internet exchange? Remember my neighborhood at 3pm when all the kids start streaming YouTube videos and the neighborhood becomes congested? Now imagine you are Google who owns YouTube and has to buy expensive internet circuits to keep up with all of the demands of it’s users. As the IX world grew, the market for opened to enterprise internet consumers as well.
Imagine for a moment that your company uses Comcast, and have created a VPN to another company that you are sharing data with that uses Verizon. If you were to trace out that dynamic path between your two networks you may find that Verizon hands off FiOS Business customers from the Baltimore market in a Northern Virginia IX. But Comcast hands off business clients in the Baltimore market in either Philadelphia or New York City. Think about that one: Hunt Valley to Northern Virginia à to another provider to get to New York to connect to Comcast then à New York back to Timonium. It’s a real world scenario, and it happens more often than you think. This is why we said above…the internet is slow.
Now imagine that Comcast plugs into a port right here in Baltimore and so does Verizon. Verizon traffic goes a hundred light miles less, Comcast goes a hundred light miles less, and there is one less provider in the middle. The speed of light isn’t getting any faster. The only way to make the internet faster is to shorten the distance between two points.
Here is another example. Above we said it wouldn’t be easy to subscribe and connect to every online service? What if you could in fact connect to all of the critical services that you rely on to make your business run? What if you could in fact connect directly to Google, Microsoft Office 365, Microsoft Teams, Amazon, and WebEx and have dedicated link to those services and use your commodity internet for the rest? With peering you can, and there are no other providers in the middle that puts your traffic even if encrypted at risk.
Here is another example. Above we talked about building out a VPN between your company and another to share information for a research project you are doing together. VPNs are common place, but to this day are somewhat difficult to set up site to site. What if you and the other company were both Internet Exchange subscribers and with only a service order could have a completely private connection established between your two organizations. That too is the promise of peering.
Peering while not new is opening the doors to wildly new ideas in the way we interconnect our local networks to the rest of the world. The concept of peering is not revolutionary, but it is being used in revolutionary new ways, and is growing in popularity. Whether you call it SD-WAN, private network connectivity or managed virtually private networks, it’s slowly becoming a business need.