Open Computer Network

OCN (オーシーエヌ), or Open Computer Network, is the largest Japanese Internet service provider, with over 7 million subscribers. It is owned by NTT Communications Corp, one of the largest telecommunication companies in the world. It offers dial-up and ISDN, DSL up to 50 Mbit/s and fiber up to 200 Mbit/s download and 100Mbit/s upload.

As a result of regulations intended to promote competition, OCN themselves offer only internet service (routing); the physical line can be offered by NTT (the parent corporation), or by another company. (Likewise, one can lease a"Flets" fiber line and use Sony, Nifty, or another internet provider). Speeds up to 1Gbit/s are offered in Western Japan, while in East Japan only 200Mbit/s is officially offered for residential use, even though the underlying fiber infrastructure is capable of 1Gbit/s.

OCN also offers an MVNO mobile broadband service called "OCN Mobile One", based on NTT Docomo's LTE infrastructure, but with data only SIM cards issued by OCN. Cards with and without SMS access are available. (In a tie-up with NTT Communications, one can install the "050+" application and use voice over IP so that the data only SIM cards can be used for voice as well.) Recently a voice sim option has also become available.

Open Computer Network is one of the largest spam e-mailing networks. The parent company NTT Communications Corporation blatantly refuses to do anything to fix their highly vulnerable Open Computer Network. Thus, there are countless and endless worldwide complaints of spam e-mail against Open Computer Network.

See also

• Verio

External links

• Official OCN website
• Start of OCN Business Web Service and its Future at Science Links Japan
• NTT communications
• OCN known as ocn.ad.jp is also the source of a large number of phishing spam emails and Malware distribution activity
• Discussion regarding ocn.ne.jp as a source of spam/malware