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The Internet Backbone

UN_Geneva_DSC_0096
(United Nations, Geneva, Switzerland - Alvin Wei-Cheng Wong)

 

Internet Backbone Technology

 

In computer networking, a backbone is a central conduit designed to transfer network traffic at high speeds. Backbones connect local area networks (LANs) and wide area networks (WANs) together. Network backbones are designed to maximize the reliability and performance of large-scale, long-distance data communications. The best-known network backbones are those used on the Internet.

The Internet backbone may be defined by the principal data routes between large, strategically interconnected computer networks and core routers on the Internet. These data routes are hosted by commercial, government, academic and other high-capacity network centers, the Internet exchange points and network access points, that exchange Internet traffic between the countries, continents and across the oceans. 

Nearly all Web browsing, video streaming, and other common online traffic flows through Internet backbones. They consist of network routers and switches connected mainly by fiber optic cables. Each fiber link on the backbone normally provides 100 Gbps of network bandwidth. Computers rarely connect to a backbone directly. Instead, the networks of Internet service providers or large organizations connect to these backbones and computers access the backbone indirectly.

Internet service providers participate in Internet backbone traffic by privately negotiated interconnection agreements, primarily governed by the principle of settlement-free peering. The interactions between large corporations and their agreements for sharing each other's networks also tend to complex business dynamics. 

Due to their central role on the Internet and global communications, backbone installations are a prime target for malicious attacks. Providers tend to keep the locations and some technical details of their backbones secret for this reason. Although the Internet is publicly accessible, it is woven together from many privately owned networks that interoperate. Telecommunications companies sometimes show schematics of their core networks, but without much geographic detail. Knowing the exact location of the most important Internet cables should help efforts to understand the possible effects of natural disasters or intentional attacks on the Internet.

 

Architectural Principles


The Internet, and consequently its backbone networks, do not rely on central control or coordinating facilities, nor do they implement any global network policies. The resilience of the Internet results from its principal architectural features, most notably the idea of placing as few network state and control functions as possible in the network elements, and instead relying on the endpoints of communication to handle most of the processing to ensure data integrity, reliability, and authentication. In addition, the high degree of redundancy of today's network links and sophisticated real-time routing protocols provide alternate paths of communications for load balancing and congestion avoidance.

 

Infrastructure

 

The Internet backbone is a conglomeration of multiple, redundant networks owned by numerous companies. It is typically a fiber optic trunk line. The trunk line consists of many fiber optic cables bundled together to increase the capacity. The backbone is able to reroute traffic in case of a failure. The data rates of backbone lines have increased over time. Fiber-optic cables are the medium of choice for Internet backbone providers for many reasons. Fiber-optics allow for fast data speeds and large bandwidth; they suffer relatively little attenuation, allowing them to cover long distances with few repeaters; they are also immune to crosstalk and other forms of electromagnetic interference which plague electrical transmission.
 
 
  • [CNN Labs]: What the Internet looks like: The undersea cables wiring the ends of the Earth. The information age is powered by thin fiber-optic cables buried in the sea bed, spreading between continents to connect the most remote corners of the planet. These great arteries account for practically all of our international web traffic, and each one has been logged by Washington research firm Telegeography in its interactive Submarine Cable Map 2014. (click here to find out more).
  • [Vox]: 40 maps that explain the Internet: The internet increasingly pervades our lives, delivering information to us no matter where we are. It takes a complex system of cables, servers, towers, and other infrastructure, developed over decades, to allow us to stay in touch with our friends and family so effortlessly. Here are 40 maps that will help you better understand the internet — where it came from, how it works, and how it's used by people around the world.
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    Modern Backbone

     

    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 web, it is necessary to have backbone routers, which are routers powerful enough to handle information on the Internet backbone and are capable of directing data to other routers in order to send it to its final destination. Without them, information would be lost.

     

    Core Router (Internet Backbone Router) and Edge Router

    [Wikipedia]: A core router is a router designed to operate in the Internet backbone, or core. To fulfill this role, a router must be able to support multiple telecommunications interfaces of the highest speed in use in the core Internet and must be able to forward IP packets at full speed on all of them. It must also support the routing protocols being used in the core. A core router is distinct from an edge router

    Edge routers sit at the edge of a backbone network and connect to core routers.

     

    Routing protocol


    [Wikipedia]: A routing protocol specifies how routers communicate with each other, disseminating information that enables them to select routes between any two nodes on a computer network. Routing algorithms determine the specific choice of route. Each router has a priori knowledge only of networks attached to it directly. A routing protocol shares this information first among immediate neighbors, and then throughout the network. This way, routers gain knowledge of the topology of the network.

    Although there are many types of routing protocols, three major classes are in widespread use on IP networks:

     
     
     

     

    [More to come ...]

      

     


     
     
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