Published on December 20, 2021
Although almost everyone uses the Internet nowadays, few are those who really know how it works. BGP routing, transit, peering, CDN, Tier-1 providers: here are a few explanations to help you see clearer and be able to distinguish between the various network operators.
“At the highest level, the Internet is an amalgam of clouds,” describes Samuel Tanguay, a customer network specialist at fibrenoire. It’s private and public networks that connect together, allowing users to access content, no matter where they are in the world.
These networks come in many forms and are not strictly limited to Internet providers. Content providers, like Amazon and Google, or any other company that purchases IP addresses and connects to a provider, can also be a part of the Internet, as long as they have an ASN (Autonomous System Number).
“This number identifies your network and allows you to advertise to others what IP addresses you own and wish to make available online,” explains Tanguay. It’s the BGP (Border Gateway Protocol), or exterior gateway protocol, that manages these information exchanges between different AS (Autonomous Systems).
To navigate from one IP address to another (from a company computer to a web server in the United States, for example), information can pass through a multitude of Autonomous Systems, or be transferred from the departure AS to the final AS if a connection exists between the two. “The shortest route will be chosen by default,” points out Tanguay.
The shorter a route is, the lower the latency time. Thus, the more an operator is capable of offering short routes to its users, the better its services will be.
Transit, peering, and CDN: the crux of it all
In an ideal world, all Internet service providers would be directly connected to all the networks. In reality, such an option isn’t very feasible. “There are thousands of entities online; it’s impossible to be directly connected to everyone,” says Tanguay. However, an Internet service provider wants its customers to be able to access all the IP addresses in the world, even if the provider himself isn’t directly connected to said addresses.
“In such situations, when there’s no direct access to the network the customer wants to reach, we transit via an intermediary,” explains the customer network specialist. Sometimes, we need to jump between numerous networks in order to go from point A to point B. To minimize the number of intermediaries, a service provider can, if they want, purchase Internet from a tier-1 provider, like TATA Communications or Telia. There exists 15 or so providers like this in the world, some with over 800,000 km of fibre optics. “These are big, international players with a significant network of connections,” says Tanguay. Fibrenoire is connected to several different providers in order to ensure optimal service across the globe.
This way of proceeding, called transit, allows users to access all of the Internet. Even though it’s a more optimal solution than jumping from one network to another, “it isn’t the ideal route, seeing as we must pass through an intermediary network and multiple routers,” explains Tanguay. Not only is the latency higher for users, but the provider must pay per connection. “There’s a technical advantage for the customer and a financial advantage to avoiding such links,” concludes Tanguay.
To improve the transfer of information between two networks, it’s possible to directly link the two with a physical connection, also known as peering. This allows traffic to pass from one network to the other without having to rely on an intermediary, meaning latency is kept to a minimum. Both technically and financially speaking, everyone wins.
Fibrenoire, for example, has several direct links (PNIs, or Private Network Interconnects) with big-name players such as Google, Microsoft, and Amazon, seeing as a lot of its traffic is directed towards them. Obviously, such links cannot be installed towards all data centres. “It would be a tedious process connecting directly to 500 networks,” says Tanguay.
To resolve this issue, several industry stakeholders have implemented IXPs (also known as Internet Exchange Points)—locations through which several networks can connect, sort of like a multimodal station. The Montréal Internet Exchange (QIX), for example, connects 93 different AS. They service Internet providers like fibrenoire, as well as video game companies like Riot Games, television channels like Radio-Canada, the Canadian government, and many more.
As soon as a user attempts to access an IP address that belongs to one of these networks, the connection is direct, the latency low, and the cost free for both parties.
In addition to the Montréal exchange, fibrenoire also participates in exchanges in Toronto, Vancouver, and New York, which gives them 473 direct IPV4 connections and 298 direct IPV6 connections (at the time of publication). In both instances, it’s more than any other provider in Canada. The exact number of connections can vary at any time, as AS are continuously added or removed from the IXPs.
“We’re extremely proud of being able to offer as much peering as possible,” exclaims Tanguay. With such a comprehensive peering offer, fibrenoire customers are more likely to benefit from direct routes when they join a server.
Peering isn’t the only efficient way to access a server. Content providers, like Netflix and Google, are increasingly offering Internet access providers the possibility of hosting their data cache directly on their network—a process that’s called CDN, or Content Delivery Network.
A Netflix cache could, for example, contain all of a region’s most popular TV series, while a Google cache could include YouTube’s trending viral videos or the most-searched content. Akamai, a global cache provider, could store Radio-Canada content during the Olympics, seeing as such content is seen by a high number of people at the same time. “Content providers do not, however, publish what they store in their cache,” points out Tanguay.
Not all Internet access providers have a CDN. “A small, local provider wouldn’t have a cache, seeing as you need a minimum volume in order to be eligible,” says the customer network specialist.
When the content searched for by a customer is stored in a CDN, the data doesn’t even leave the access provider network. It’s the most advantageous option, both for the customer, who benefits from low latency, as well as the provider, who can save on their IXP connections and avoid having to transit. And it’s also the ideal option for content providers, who can reduce the traffic towards their data centres.
CDNs are also good for the Internet’s infrastructure. Caches help reduce the charge on Internet backbones and IXPs, seeing as the traffic never leaves the access provider’s network.
Tier 1, Tier 2, Tier 3: seeing through the marketing
Oftentimes, Internet service providers are classified Tier-1, Tier-2, or Tier-3. But what does this mean, exactly?
“The tier concept is a marketing tactic,” warns Tanguay. The definition is somewhat flexible and varies depending on who you ask. And some providers, including big-name tier-1 Canadian providers, like to portray themselves as bigger than they really are. “We don’t do that,” states the customer network specialist.
“For us, a tier-1 provider is someone who never buys Internet. It’s a provider that is so massive, that others want to access their network. Tier-1 companies do peering with other tier-1 companies, and sell their Internet to tier-2 providers,” explains Tanguay. Occasionally, tier-1 providers don’t even sell their Internet to individuals. This definition is the one most widely used and accepted by the industry.
In this vein, fibrenoire, which buys Internet from other providers around the world (including big-name Canadian providers) qualifies as a tier-2 provider. Internet access providers who buy their Internet from fibrenoire are considered tier-3.
The important thing is not necessarily how a company identifies itself, but rather the quality of its network. The best way for a customer to reach their destination online will always be via the fastest route. The more a service provider is able to offer direct links to sought-after content, whether that’s through peering or CDN, the better their service will be.