Japan’s multiple network redundancy stands well post-quake

The density of the network in Japan and the diversity within and outside its shores, and the installation of specialized local operators of civil works, helped to ensure the soundness of the country’s telecommunications network in the aftermath of the earthquake March 11, according to one industry analyst.

However, the fixed communication devices are still vulnerable to eating disorders and the problem will increase as the number of consumer devices networked to the fixed network grows, said David Kennedy, Ovum research director, in a report released Wednesday.

The earthquake of magnitude 9, which also caused tsunami waves has shown that users are increasingly dependent on mobile communication devices, Kennedy said, noting that the telecommunications network traffic grew exponentially after tremor as customers tried to contact loved ones.

Major Japanese telecommunications companies have been restored from various fixed and mobile services in the areas most affected, but the fixed service disruptions remains a challenge. He added that operators are likely to prioritize repairs to the mobile network via the fixed communication because the latter is still vulnerable to rolling blackouts, caused by shortages of energy from nuclear plants damaged.

KDDI that do not work there were 1,500 base stations, down from 3. 800, while Softbank reduces their base stations out of service from 3786 to 1157, he said. NTT DoCoMo also reported that its 2130 phone base stations were not yet out of service, compared to 6720 that were inoperable immediately after the earthquake, he added. [Editor’s Note:. From 1 pm on March 23, local time, the number of base stations inoperable dropped to 840]

The operator also rented satellite phones 830 and 1184 mobile phones, 30 mobile units deployed from the base station and mobile vehicle power supply, mobile power generators 400 and 100 free mobile phone charging stations, to provide access to telecommunications in areas without mobile phone reception.

From 1 pm on March 23 in Japan, NTT East said it restored 90 percent of its 1. 000 exchange offices damaged by the earthquake and the power supply is recovered commercially. He noted that 93 exchange houses and tours of approximately 155 000 have not yet been restored.

The company added that a significant amount of time would be needed to recover the remaining offices, because the damage extended beyond physical harm, and included flooding or broken connection to the backbone transmission lines in areas severely affected, and out of bounds around the damaged nuclear power plant.

Kennedy noted that several undersea cables damaged in the quake, but service providers had been able to resolve the outage efficiently due to the strong network of Japan. And while there were interruptions in international communications as a result of cable breaks reported, the connectivity was “surprisingly strong,” especially when compared with the 2006 earthquake in Taiwan.

Kennedy explained: “The density and diversity of networks within and outside of Japan creates many redundant pathways, which prevented the outage of importance outside the affected areas.

“[In addition], the operators had installed specialized civil works that can cope with earthquakes, having learned many lessons from the Kobe earthquake of 1995. Flexibles underground conduits between the infrastructure of streets and buildings, sliding joints of the ducts to relieve the axial forces and joint flexibility in the access tunnels to wells and others have become common in new installations since 1995, “he said.

Although repair work is progressing steadily, Ovum expects the new issues to the surface in the coming weeks as damaged infrastructure – both on land and at sea – no.

Kenney said the earthquake vibrations can cause the ground to liquefy, damaging wells, pipelines and cables. This would allow water to enter and damage to submarine cable systems, the most network failures weeks after the earthquake, he added.