Submarine Cable Networks - The Artery Connecting the Internet World

Submarine Cable Networks - The Artery Connecting the Internet World

By Mike Ng, Vice President - Product & Service Development, SUNeVision 

You might have heard from recent news that those hyper-scale Internet players such as Google, Microsoft, Facebook and other Global Internet companies have all participated in the submarine cable investment. They have put up huge investment and some of them even have built their own cable systems to support their dramatic growth in global bandwidth demand. This new impetus has invigorated the industry which traditionally considered belong to the “Club Community” of incumbent operators in the telecommunications industry. However, how much do you know about this so-called traditional industry?

<Submarine Cable systems in Asia-Pacific region>


The Development of Submarine Cable System

In the early 80s, telecommunications services were dominated by voice service, which consumed a small amount of bandwidth per circuit (only 64 kbps required for each voice line). The construction of submarine cable networks was a capital-intensive infrastructure investment, which incurred hundreds of millions of US dollars to complete, while each telcommunications participant could only built their own facilities in their respective territory. Even worst, the fibre-optics transmission technology at that time only supported a low speed rate at 140Mbps - 565Mbps or 2.5Gbps level, the investment was not cost-effective anyway. Global telecommunications facilities were, therefore, dominated by satellite-based systems. However, the rapid growth of the Internet user base and bandwidth-hungry applications in recent years has been boosting the bandwidth demand. With the advancement of fibre-optics transmission technology, submarine fiber-optic based system now reaches a bandwidth of more than 10Tbps, which has turned today’s global telecommunications platform to adopt submarine fiber-optic cable-based systems.


Types and Nomenclature of Submarine Cables

There are two types of submarine cables, mainly classified by their investment methods, including Club Consortium Cable (such as APCN-2, APG, AAE-1, SEA-ME-WE 5) and Private Cable (such as FNAL, PLCN), named based on the areas they are connected to or the companies' names, e.g. SEA-ME-WE 5 is South East Asia - Middle East - Western Europe 5 and FNAL is FLAG North Asia Loop. In the early days, because the telecommunications market around the world was not yet open, most of the submarine cables were built by Club Consortium, among those incumbent telecommunications operators in the world. As a submarine cabling project involved interests of multiple telecommunications companies, the entire process, from business negotiation to construction, would take 2-3 years to complete. With the liberalization of the telecommunications market in various countries since 2000, more submarine cables were built on behalf of private companies, and the time required was also shortened to 18-24 months.

For a period of time, the design of submarine cables was mainly based on "Point-to-Point" or "Fish-bone" Topology, backed up with a "Ring" design. Taking into consideration of the relatively high latency, "Ring" designed has seldom been adopted in recently built cable systems. The determining factors of submarine cable networks capacity shall be subject to three factors, namely the number of fiber-pairs, the number of wavelength channels being used by the cable system, along with the transmission speed rate per wavelength channel. The PLCN, co-built by Google and Facebook, for instance, used 5 pairs of fibers. The design capacity of each pair of fibers can transmit 240 channels of 100Gbps, hence the entire cable system can provide up to 120Tbps of capacity.


The Development of Submarine Cable Systems in Hong Kong

As a matter of fact, Hong Kong is geographically located in the centre of the Asia-Pacific region, and since the Office of the Communications Authority (OFCA) has liberalized the external facilities-based telecommunications market as early as 2000, Hong Kong has been adopting an open licensing regime i.e. there is no limit on the number of external facilities-based licenses. Many of the submarine cable systems in the region have chosen Hong Kong as one of the important landing sites. At present, there are about 15 major submarine cable systems in the region, of which 12-13 have chosen Hong Kong as one of their landing sites. This is one of the key successful factors for Hong Kong to become a major telecommunications hub in the region.

In fact, there are not many available sites for submarine cable landing in Hong Kong. Other than Tseung Kwan O, all available sites are located in the southern part of Hong Kong Island and Lantau Island (including: Tong Fuk, Deep Water Bay, Chung Hom Kok and Cape D'Aguilar) (see "Map of Landing locations of Major Submarine Cables in HK" below). In view of this, most of the submarine cable operators and telcommunications operators who have participated in Consortium Cable would build their City Point-of-Presence (City PoP) in high-tier data centre in the urban area to facilitate the connection between the submarine cables and enterprise and telcommunications customers. This approach definitely reduced customers' cost in backhaul connections to the submarine cable landing stations.

Map of Landing locations of Major Submarine Cables in HK

<Map of Landing locations of Major Submarine Cables in HK>

Taking SUNeVision Data Centres as an example, there are already 10 Asia-Pacific major submarine cable systems (see Table of Submarine Cable PoP at SUNeVision Data Centres below) who chose to build City PoP sites/operations there, which has also led to the dense of presence of regional (and even global) telecommunications companies and Internet companies. In addition, in order to reduce the local loop costs to connect with these submarine cable systems, as well as to achieve higher stability and better network performance, customers tends to choose data centres with more submarine cable PoPs. All these have added up to make Hong Kong an important telecommunications hub in the region.

Table of Submarine Cable PoP at SUNeVision Data Centres

<Table of Submarine Cable PoP at SUNeVision Data Centres>


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