For the most part, undersea communications cables appeared to have...

and at least two other cables were damaged. Some of the undersea cables in the Asia-Pacific region that Verizon participates in were damaged, a spokeswoman said. But the company’s eighty-way “optical meshing” diversity in the Pacific allowed the network to stay operational before, during and after the earthquake and numerous aftershocks, she said. The technology allows traffic to be automatically re-routed onto different submarine cables when a network event occurs, she said. The Verizon local networks in Tokyo and Osaka continued to operate normally, as did its global network, the spokeswoman said. The company has been helping several other affected providers restore services, she said. Sprint Nextel hasn’t experienced any effects on its network assets or service following the disasters, a spokeswoman said. Japan’s Internet has held up since the earthquake, according to Internet monitoring firm Renesys. Only about 100 of roughly 6,000 Japanese network prefixes in the global routing table were temporarily withdrawn from service -- and that number has decreased since the event, said Renesys Chief Technology Officer James Cowie. Other carriers around the region have reported congestion and drops in traffic due to follow-on effects of the quake, but most websites are up and operational, and the Internet is available to support critical communications, he said. Compared to the 2006 Taiwan earthquake, which resulted in a larger number of major cable breaks, it appears that the majority of the region’s submarine cables have escaped the worst damage, and diverse capacity remains to carry traffic around the points of damage, he said. The western and northern sections of the Pacific Crossing-1 undersea cable system connecting the U.S to Asia were still out of service Monday, said Pacific Crossing, a subsidiary of Japanese operator NTT Communications. The company is inspecting the damage and is accelerating the restorations activities, it said. PC-1 is a 13,049-mile fiber ring that lands at two sites on the U.S. west coast and two sites on Japan’s east coast. NTT said backup cable routes were used to support traffic between Japan and other parts of the world. There are 20 trans-Pacific and intra-Asia cable systems that land in Japan, according to research firm Telegeography. Overall, the undersea cable network has experienced limited damage, the firm said. AT&T is working to reduce some customer impact from damage to undersea cables that are operated by the APCN-2 consortium, a group of some 14 global service providers, including AT&T, a spokesman said. APCN-2 is an undersea cabling network that connects ten landing points across Asia-Pacific, including China, Hong Kong, Japan, South Korea, Malaysia, the Philippines, Singapore and Taiwan. AT&T is re-routing affected customers’ traffic to unaffected circuits and will ensure customers have minimal service disruption, the spokesman said. Still, some networks remained out of service. Japanese operator KDDI said one of its undersea cables between Japan and the U.S. has been damaged and is unable to transmit any signals. Korea Telecom also said a segment of the Japan-U.S. Cable Network is damaged. Several Chinese telecom operators reported slower speeds and other disruption of Internet services.