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The public Internet is a complex mesh of almost one hundred thousand different, but ‘open’ networks - linked together with an almost limitless inventory of network hardware and millions of kilometers of fiber-optic cable. In technical terms, these are known as Autonomous Systems (AS). An AS is essentially a unique collection of IP addresses/address blocks and network hardware within a common administrative domain. Autonomous Systems communicate route information and steer traffic to each other using a protocol known as the Border Gateway Protocol, or BGP.

At the core of the Internet is the Internet backbone. Here, the largest and fastest networks are linked together with fiber-optic connections and high-performance routers. Internet networks are primarily owned and operated by commercial, educational, government or military entities. Collectively, they facilitate a stable foundation for the Internet Service Providers (ISPs), content and cloud providers who provide Internet access or online content, applications and services to end-users and businesses.

The largest providers are known as Tier 1 networks. Positioned at the top of the Internet ecosystem, these networks are sufficiently comprehensive that they don’t purchase IP Transit from anyone else. Tier 1 networks exchange Internet backbone traffic on the basis of privately negotiated interconnection agreements, usually on the principle of settlement-free IP peering. In general, networks lower down in the hierarchy pay for upstream IP Transit and networks of similar size and merit peer with each other. There are a dozen global Tier 1 providers today, of which Arelion (AS1299) is one of the largest and best connected. 

Illustration of What is the Internet backbone?

What makes a good Internet backbone?

Whilst Internet connectivity is often viewed as a commodity, performance can vary significantly between suppliers. When selecting an Internet backbone, there are a number of important things to consider:

Reach - a larger footprint generally means a service provider has greater control of network resources, and ultimately, quality.
Scalability - is a backbone built on leased capacity or own infrastructure? This will dictate the ability of a supplier to scale-up capacity, quickly and efficiently.
Proximity - How well connected is a backbone with the rest of the Internet and in what tier do they reside?
Connectivity – Does a backbone connect via third party transit networks and public exchanges or through a well-managed ecosystem of private peering connections with critical networks?

The network of networks

Serving customers in 125 countries, our 70,000 km fiber backbone spans North America, Europe and Asia. Our PoPs give you a direct route to the world’s best content and billions of end-users. Fiber-up control of our network with cutting-edge optical and IP technology deliver the scalability you need, whenever you need it.

BGP and Routing

BGP (Border Gateway Protocol) routing is the central nervous system of the Internet. Stable and efficient IP routing between different Autonomous Systems (AS) is essential for the security of the entire Internet ecosystem. Our BGP communities and the added security of RPKI enable manageable and reliable traffic flows.

Looking Glass

Whether you're just curious or need some tools to check your connectivity, our looking glass puts you at the heart of our network.