I started my short blog series last week on the world-wide undersea fiber optic cable systems with a history of undersea cable systems and a high-level overview of the components of a cable system. Now that you understand how the cable systems came about and what parts are involved, this week I'll go over how cable systems are deployed and repaired and finish with some facts on the world's current undersea cable systems.
Laying a new cable system can often be a multi-year effort. From business opportunity recognition, to requirements definition, to landing zones, to contract, to cable construction, to implementation, to testing.....you get the idea. It can take a while. A few companies specialize in undersea cable deployments. Alcatel-Lucent is one. Alcatel-Lucent provides a wide array of hardware, software, facilities, and services to carriers. Alcatel even maintains its own fleet of ships to maintain cable systems for customers. Surprising to think that a telecom company like Alcatel has a fleet of ships. Sort of like eBay owning Skype......errr......never mind..... Anyways, companies such as Alcatel can be contracted with to deploy new undersea cable systems. Once the fiber is ready, Alcatel uses its ships to deploy the cable in essentially 6 steps:
- Float the cable from the deployment ship to the shore to be connected to the landing station.
- Disconnect the cable from the floating buoys and allow it to fall to the ocean floor, typically the continental shelf.
- Use a Remote Operated Vehicle (ROV) - essentially an unmanned submarine - to bury the fiber optic cable under the ocean floor. This keeps the sharks, fishing boats, rock slides, and currents from affecting the cable. It also makes it harder for spy agencies - like the CIA, NSA, KGB and other agencies with TLAs - to find the cables and tap into them.
- Continue across the ocean, adding repeaters where necessary. The ROV continues to bury the cable.
- On the other side of the ocean, repeat step #1 - float the cable from the deployment ship to the shore to be connected to the landing station.
You now have an undersea fiber optic cable deployed. Alcatel has a very nice flash demo which shows this process. Unfortunately, events often occur that cut undersea fiber optic cables. This can lead to massive outages, particularly in countries with limited and/or restricted Internet access. Carriers have gotten much better in the past few years dealing with undersea cable faults. Service restoration prioritization - for example, private MPLS services over general Internet - is done automatically now by optical mesh clouds based on standards such as GMPLS. Verizon often touts its optical mesh technology for undersea cable systems. However, when a cable cut occurs, it has to be fixed. Fixing a cable cut is done with the same ships that laid the cable in the first place. ">
Today's undersea optical cable systems are a vast array of fibers, branches, meshes, and landing points. Alcatel provides some nice maps of the cable systems they have worked on. There is no one map I know of that shows every cable system. THERE ARE JUST TOO MANY OF THEM! Verizon has a simple, interractive map of the systems they use. This is also a good map of the current major intercontinental (always wanted to use that word in a sentence!) cable systems. The best list of all international undersea cable systems shows - by my best count - 288 individual cable systems. And remember, each system may have multiple cables. And each cable has multiple fibers in it. And each fiber, with Dense Wave Division Multiplexing (DWDM), can transfer many point-to-point connections on different lambdas. This takes the capacity of a single undersea fiber system into the Terabits. The longest undersea cable system in the world - SEA-ME-WE-3 or South-East Asia - Middle East - Western Europe 3 - can transfer over 960 Gbps, close to 1 Tbps. SEA-ME-WE-3 has 39 landing points from Korea to Germany spanning 24,000 miles. Optical Branching Units allow SEA-ME-ME-3 to drop off connections into countries along its route; such as India, Pakistan, Turkey, and Greece. SEA-ME-WE-3 has been so successful, SEA-ME-WE-4 has been built.
All of these amazing cable systems are truly a marvel of science and innovation. The ability to do a ping from North Carolina to India in under a quarter of a second:
US-DUR-CR01-B1DCA04>ping Bangalore-rtr
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.111.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = <font color="red">224/224/224 ms</font>
is just incredible.
More >From the Field blog entries:
The Incredible International Submarine Cable Systems
Tons of Great Content from Webtorials
Our New Data Center is A-L-I-V-E !!!!
Phase Two of our New Data Center Project has Begun
Cisco Advanced Services Education and the Awesome Technical Knowledge Library
My Interview with Cisco about the CCDE
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