Continued… Part VI – Cable Size and Comparing Submarine Cables vs Satellite.

Today, I’ll discuss on the submarine telecommunications cable physical size and the comparison between sub-cable and satellite.

  • Modern submarine telecommunications cables are small; deep-ocean types without protective armor are typically 17-20 mm diameter, similar to that of a garden hose.
  • Armored fiber-optic cables on the other hand may reach 50 mm diameter.
  • In contrast, submarine oil/gas pipes reach 900 mm diameter, and fishing trawls typically range over 5,000 – 50,000 mm width.
  • Cable lengths vary; one of the longest is the SEA-ME-WE 4 system at ~20,000 km SEA-ME-WE 3 system at ~39,000 km.

Below is a diagram to better illustrate the size comparison:

Modern fiber-optic cable in hand (for scale) and relative to 300mm diameter subsea pipe.

There is a common misconception that nowadays most international communications are routed via satellites, when in fact well over 95% of this traffic is actually routed via submarine telecommunications fiber-optic cables. Data and voice transfer via these cables is not only cheaper, but also much quicker than via satellite.

In 1988, the first trans-oceanic fiber-optic cable was installed, which marked the transition when submarine telecommunications cables started to outperform satellites in terms of the volume, speed and economics of data and voice communications.

However, despite  the  success  of  submarine  telecommunications, satellite transmission remains a necessary adjunct. Satellites  provide  global  broadcasts  and  communications for  sparsely  populated  regions  not  served  by  cables. They also form a strategic back-up for disaster-prone regions.

Below are the advantages comparison between submarine telecommunications cables and satellites.

Main advantages of sub-cables

  • High reliability, capacity & security.
    • Securely  and  consistently deliver  very  high-capacity  communications  between  population  centers.
  • None of the delays present in satellite traffic
  • Cost-effective on major routes, hence rates cheaper than satellites
    • The advantages  of  low  cost  and  high  bandwidth  are  becoming attractive  to  governments  with  low  population  densities.

Yield: Submarine cables carry >95% of international voice & data traffic.

Almost  all  transoceanic telecommunications  are  now  routed  via  the  submarine cable network instead of satellite.

Main advantages of satellites

  • Suitable for disaster-prone areas
  • Provides wide coverage for mobile subscribers
  • Suitable for linking isolated regions and small island nations into the international telecom network

Yield: Satellites carry <5% of international voice & data traffic

Source: International Cable Protection Committee Ltd

To be continued… Part VII – Strategic Importance of Submarine Cables, Coastal Cable Routes and International Cable Routes.