Some prospective customers challenge us as to why we think it’s important to have as many transit providers as we do. They often state that a competitor they are comparing us to has four or five providers, which is more than adequate for the sake of redundancy, and more than most other competitors. Actually, we would agree, but only with the fact that four or five providers is sufficient for redundancy. The likelihood of all five transit providers failing and causing a complete outage is highly unlikely (unless, of course, they all enter the building via the same conduit or fiber).  But redundancy is only one reason to have multiple providers. After ten years in the data center business, we've come to the conclusion that having a connection to every provider offers a superior blended Internet product for significant reasons.

Prior to vastly increasing the number of transit providers in our bandwidth mix, our clients would periodically ask if we could improve routing from point 'A' to point 'B' with the hope of shaving a few milliseconds off a route or with the goal of getting around latency deep within a network that was outside of our control.  Adding additional transit providers offered us three unique advantages with greater control over our network and dramatically improved performance for our customers. Let me explain each of these benefits in more detail.

More transit providers means better physical fiber routes
Not every provider uses the same physical fiber path to go from one city to another or even from one country to another. Fiber generally follows power line right-of-ways, railroads, interstate highways and other convenient paths. And while it is true that smaller providers lease capacity from larger providers to build their networks, there are numerous providers who have spent great deals of money running physical fiber around the country and around the world. Additionally, there are numerous regional fiber providers who have run fiber spanning multiple states. These providers often enter into agreements with other regional providers to create larger, multi-regional networks that can offer seamless capacity often spanning multiple states.

Here's a simple scenario to show you what I'm talking about. Let's take Level(3) and AboveNet , both of which are part of our 15+ provider Internet blend. As shown in the thumbnail images below (click for a larger image), you'll see that from Atlanta to Chicago, Level(3) has a direct path where AboveNet does not. AboveNet would have to get there via Houston or Washington D.C. Obviously, going via Houston or D.C. adds several thousand miles to the trip; and for every 100 miles, approximately 1 millisecond of latency is added. So, if we had to make a routing decision based solely on latency, Level(3) would most definitely get the traffic.

AboveNet (click to enlarge)	Level(3) (click to enlarge)

Of course, the opposite would be true if we were sending traffic to a client in Houston in which case AboveNet has a more direct path where Level(3) does not. So using this example, if we did not have a connection to Level(3), customers with servers in Atlanta and clients in Chicago would probably get upset with the high latency between the two cities.  Having a connection to both of these providers creates a better performing bandwidth product than having just one. Imagine how infinitely better it can be with 15 providers.

Sending traffic overseas is even more sensitive due to the large distances that need to be covered. Again, with the Level(3) and AboveNet example, if a client were in London and the server in Atlanta, AboveNet would route up to Washington D.C. and then out under the ocean to London where Level(3) would take it up to New York. In that scenario, it may be possible to shave 10ms off of the round trip, which can be significant for VoiP or other latency sensitive traffic. Furthermore, with the frequency of undersea cable cuts affecting global traffic in a significant way, having as many routes as possible makes the network less susceptible to these types of issues.

More transit providers improves logical routing
When traffic traverses only one network from client to server, things generally run more smoothly. In the past we've received the occasional call from a customer with a trace route in hand to show that a bottleneck lies between provider 'A' (which we have a connection to) and provider 'B' (which the end customer has a connection to). The trace route suggests that, at a certain hop when the traffic moves from our provider's network to another provider's network, latency increases dramatically.

Phone calls to either provider are most often fruitless. Both providers tend either to blame ICMP deprioritization and suggest the trace route is irrelevant or to point the finger at the other provider suggesting a bottleneck somewhere within their network. The truth is, as soon as their network engineers see that the perceived bottleneck is outside of the network they have access to, they take the position that the issue is not theirs.

Our method of getting around this is to get a direct connection to as many providers as we can in as many peering locations as possible. Our ultimate objective is to have a connection to the same provider that almost every one of the clients have who connects to infrastructure at our data center. As you might imagine, that is no small undertaking, but it is the easiest way to avoid finger pointing. If the traffic enters network 'A' at the datacenter and goes all the way to the client on the same network, there is no one else to blame but network 'A' when problems with latency or packet loss arise. A single network generally improves performance as well. Network 'A' will always optimize traffic within their own network before optimizing or upgrading links to other networks, so it is win-win for us and for our customers.

Another issue to consider is switching delay and queuing delay. Providers who have numerous router hops along a path to get from point 'A' to point 'B' add additional latency. Every router or switch that needs to process packets to forward it along to the destination adds a small delay. So a provider who has end-to-end fiber that traverses fewer routers or switches will most likely offer slightly lower latency, assuming the physical fiber path is identical. Of course, today's high-capacity routers and switches add very little delay, usually in the neighborhood of 150 to 200 microseconds (1/5 of a millisecond) compared to many years ago. But it is important to note especially for long routes that even today's best routers could add a couple milliseconds on a several-thousand mile trip.

More transit providers mitigate peering disputes
We've all heard how Cogent and other providers disagree when it comes to peering. Cogent has had peering disputes that resulted in serious Internet issues with at least 5 providers in as many years. From what we've read in the news, each of these disputes resulted in Cogent customers being unable to reach the customers of the peering partner and vice-versa. 

To illustrate how this could impact our customers, let's use the Cogent-Telia dispute. If we had only a connection to Telia and not Cogent, then during the dispute we would be unable to reach Cogent customers. During such a dispute, customers don't care who is at fault, they just want the issue resolved so they can resume business. If they were unaware of the dispute, they would most likely blame the provider or the data center that they were trying to reach.

By Netriplex having an alternate path to reach Cogent customers, traffic can move over that alternate route. Sure, it may be less optimal than the direct route, but it accomplishes the goal of ensuring redundancy and reachability. Of course my analogy here assumes that any other providers we have do not peer with Cogent, which would be slim. But the fewer providers a data center has in their mix, the greater the chance that this type of issue could affect them.

In conclusion, from what we've seen over the years we've been in business, more providers equals a highly superior connection. We will continue to make it our goal to peer with as many providers as we can to always improve the connectivity we provide to our customers.