Modern Internet Backbone

- Overview

The internet backbone is the high-speed, core infrastructure that connects various networks and enables global data transmission. It acts as the internet's "highway system," facilitating communication between Internet Service Providers (ISPs) and other networks worldwide. This network relies on fiber optic cables, routers, and switches to ensure fast and reliable data transfer. 

The internet is not owned by any single entity; rather, it is a network of interconnected networks owned and operated by various organizations, corporations, and individuals. While no one owns the complete infrastructure, several organizations play crucial roles in its management and standardization. 

Key aspects of the internet backbone: 

• High-Speed Connections: It utilizes high-capacity fiber optic cables and advanced routers to handle massive data volumes and ensure efficient communication.
• Global Reach: The backbone connects networks across continents, enabling worldwide communication and data exchange.
• ISP Connectivity: It provides the essential link between different ISPs, allowing them to connect and exchange data with each other and with other networks.
• Redundancy and Reliability: The interconnected nature of the backbone network ensures redundancy, meaning that if one path experiences an outage, data can be rerouted through alternative paths, maintaining connectivity.
• Managed by Various Entities: Major telecommunications companies, ISPs, and content delivery networks (CDNs) manage and operate backbone networks.
• Undersea Cables: A significant portion of the internet backbone relies on undersea fiber optic cables to connect different continents, facilitating global data flow.
• Foundation for Internet Services: The backbone infrastructure supports the delivery of internet access, applications, and services to businesses and individuals worldwide.

Please refer to the following for more information: 

• Wikipedia: The Internet Connectivity Distribution.

- No One Owns The Internet All

The backbone network of the Internet is not owned by any single company or organization. No government can lay claim to owning the Internet, nor can any company.

Instead, it is made up of multiple large interconnected networks that work together to provide seamless connectivity around the world. Some of the most well-known Internet backbone providers include Level 3 Communications, Verizon, AT&T, and Deutsche Telekom.

The Internet is more of a concept than an actual tangible entity, and it relies on a physical infrastructure that connects networks to other networks. The Internet is like the telephone system - no one owns the whole thing. 

Today, several large corporations provide the routers and cable that make up the Internet backbone. These companies are upstream Internet Service Providers (ISPs).  There are many organizations, corporations, governments, schools, private citizens and service providers that all own pieces of the infrastructure. 

There are, however, organizations that oversee and standardize what happens on the Internet and assign IP addresses and domain names, such as National Science Foundation, the Internet Engineering Task Force, ICANN, InterNIC and the Internet Architecture Board. 

Because of the enormous overlap between long-distance telephone networks and backbone networks, the largest long-distance voice carriers such as AT&T, Verizon, Sprint, and CenturyLink also own some of the largest Internet backbone networks. These backbone providers sell their services to Internet service providers (ISPs). Each ISP has its own contingency network and is equipped with an outsourced backup. 

These networks are intertwined and crisscrossed to create a redundant network. Many companies operate their own backbones which are all interconnected at various Internet exchange points (IXPs) around the world. 

In order for data to navigate this network, there needs to be backbone routers that are powerful enough to handle the information on the Internet backbone and capable of directing the data to other routers to send it to its final destination. Without them, information would be lost.

Key characteristics: 

• No single owner: The internet is a decentralized system, and no single government or company can claim ownership.
• Interconnected networks: It is a vast network of smaller networks, each with its own owner and infrastructure.
• Backbone providers: Major backbone providers like Level 3 Communications, Verizon, AT&T, and Deutsche Telekom provide the high-speed infrastructure that carries internet traffic.
• Internet Service Providers (ISPs): ISPs, such as those mentioned above, are upstream providers that sell internet access to end-users.
• Organizations for standards and governance: Organizations like the National Science Foundation, Internet Engineering Task Force, ICANN, InterNIC, and Internet Architecture Board oversee standards, IP addresses, and domain names.
• Redundant networks: Backbone networks are interconnected at various Internet Exchange Points (IXPs), creating a redundant and resilient system.
• Ownership of physical infrastructure: Various entities own the physical components like cables, routers, and servers that make up the internet infrastructure.

- Tier 1 ISPs

Tier 1 Internet Service Providers (ISPs) form the foundation of the internet backbone, consisting of interconnected networks that peer with each other to create a global network. 

These providers, including AT&T, Verizon, and others, own and operate high-bandwidth fiber-optic networks and routers. They connect their networks at peering points, which are often neutral locations with high-speed switches and routers, allowing them to exchange traffic efficiently. 

This interconnectedness allows Tier 1 ISPs to reach any other network on the internet without relying on transit agreements, making them crucial for global internet connectivity. 

Key characteristics about Tier 1 ISPs and the internet backbone: 

• Backbone of the Internet: Tier 1 ISPs own and manage the infrastructure that forms the internet backbone.
• Global Connectivity: They provide the foundation for global internet connectivity by interconnecting their networks.
• Peering Agreements: Tier 1 ISPs connect through peering agreements, which allow them to exchange traffic without paying for transit.
• No Transit Agreements: Unlike lower-tier ISPs, Tier 1 providers don't need to purchase transit services to reach other networks on the internet.
• Examples: Prominent Tier 1 ISPs include AT&T, Verizon, Sprint, NTT, and Deutsche Telekom, according to a report by ThousandEyes.

- Internet Exchange Points (IXPs)

Internet exchange points (IXP) tie the backbone together. Backbone (Tier 1) ISPs connect their networks at peering points, neutrally owned locations with high-speed switches and routers that move traffic among the peers. These are often owned by third parties, sometimes non-profits, that facilitate unifying the backbone. Participating Tier 1 ISPs help fund the IXPs, but don’t charge each other for transporting traffic from the other Tier 1 ISPs in a relationship known as settlement-free peering. Such agreements eliminate potential financial disputes that might have the result of slowing down Internet performance.

The Internet backbone is made up of the fastest routers, which can deliver 100 Gbps trunk speeds. These routers are made by vendors including Cisco, Extreme, Huawei, Juniper, and Nokia, and use the border gateway protocol (BGP) to route traffic among themselves.

- Tier 2 and Tier 3 ISPs

Below the Tier 1 ISPs are smaller Tier 2 and Tier 3 ISPs. Tier 3 providers provide businesses and consumers with access to the Internet. These providers have no access of their own to the Internet backbone, so on their own would not be able to connect their customers to all of the billions of Internet-attached computers. Buying access to Tier 1 providers is expensive. So often Tier 3 ISPs contract with Tier 2 (regional) ISPs that have their own networks that can deliver traffic to a limited geographic area but not to all Internet-attached devices. In order to do that, Tier 2 ISPs contract with Tier 1 ISPs for access to the global backbone, and in that way make the entire internet accesssible to their customers. 

This arrangment makes it possible for traffic from a computer on one side of the world to connect to one on the other side. That traffic goes from a source computer to a Tier 3 ISP that routes it to a Tier 2 ISP that routes it to a Tier 1 backbone provider that routes it to the appropriate Tier 2 ISP that routes it to a Tier 3 access provider that delivers it to the destination computer.

- Internet Connectivity Distribution

A Tier 1 network is an Internet Protocol (IP) network that can reach every other network on the Internet solely via settlement-free interconnection (also known as settlement-free peering). 

Tier 1 networks can exchange traffic with other Tier 1 networks without having to pay any fees for the exchange of traffic in either direction, while some Tier 2 networks and all Tier 3 networks must pay to transmit traffic on other networks.

[More to come ...]