NTT this week disclosed technical details about what it claims is one of the largest, most successful commercial applications of IPv6, the next-generation Internet network protocol.
NTT says Hikari-TV, an IPTV broadcasting and video on-demand service available only in Japan, has been running in production mode across its native IPv6-based, fiber-to-the-home network since March 2008.
Hikari-TV has hundreds of thousands of subscriber households in Japan, where it costs US$26 to US$36 per month. Operated by NTT Plala, the service offers high-definition and regular TV broadcasts, 10,000-plus video-on-demand titles and more than 13,000 karaoke titles.
"Hikari-TV is the first large-scale, commercially successful application of IPTV service that runs over an IPv6 network," said Cody Christman, NTT America's director of product engineering.
"You have similar offerings like IPTV in other parts of the world, but this one is using a network built from the ground up for IPv6," Christman added. "You see [companies] like Comcast struggling with how to revamp their networks to support IPv6 because we're running out of address space. Hikari-TV is the look of things to come for the U.S."
IPv6 is a long-anticipated upgrade to the Internet's main communications protocol, which is called IPv4.
IPv6 is needed because the Internet is running out of IPv4 addresses. IPv4 uses 32-bit addresses and can support approximately 4.3 billion individually addressed devices on the Internet. IPv6, on the other hand, uses 128-bit addresses and can support so many devices that only a mathematical expression -- 2 to the 128th power -- can quantify its size.
Experts predict IPv4 addresses will be gone by 2012. At that point, all ISPs, government agencies and corporations will need to support IPv6 on their backbone networks.
NTT, a pioneer in the deployment of IPv6, is providing details about its IPv6-based IPTV service as a way of encouraging more organizations to adopt IPv6.
"We have not run into any performance problems whatsoever with our IPv6 deployments or applications, with IPTV being just one of them," Christman said.
The Hikari-TV service runs on what NTT calls its Next Generation Network (NGN), a fiber-optic network that the Japanese carrier built using IPv6. NGN services, such as Internet access and VoIP, have been available to Japanese consumers since 2005.
NTT Plala's new Hikari-TV service is putting several features of IPv6 to the test, and so far those features are performing well, NTT officials say. In particular, Hikari-TV is taking advantage of the abundant address space offered by IPv6 as well as its multicast and QOS features.
Each NGN customer receives a block of IPv6 addresses that's known as a /48 -- which is more than 65,000 IPv6 addresses. This massive block of IPv6 addresses allows consumers to hook up numerous devices, such as PCs, cell phones, TVs and household appliances, to the Internet.
With IPv6, consumers can connect devices directly to the Internet without middle boxes, such as network address translation (NAT) devices, making changes to packet headers.
"NGN is the perfect network to run IPTV on top of," Christman said. "It's scalable . . . it has address transparency. There is no NAT involved. There are no kludges. It simplifies network management."
Hikari-TV uses IPv6-based unicast services, which are one-to-one communications, for video on demand, but it uses IPv6 multicast, which is one-to-many communications, for TV broadcasts. With IPv6 multicast, Hikari-TV can send a single broadcast stream out to a video server in a particular neighborhood, which saves bandwidth.
Christman said the multicast features in IPv6 are working well.
"You can do multicast on IPv4, but it has never been widely deployed," Christman said. "IPv6 was designed from the ground up to support multicast natively."
Hikari-TV also uses the QOS features of IPv6 to reserve bandwidth for IPTV, VoIP and Internet service.
"The NGN provides the end customer with a 100 megabits/sec. pipe, and whoever provides service over the NGN can carve it up as they see fit," Christman said.
NGN customers can still access IPv4-based information on the Internet because NTT uses tunneling to encapsulate IPv4 packets inside of IPv6 packets.
"It's the opposite of what a lot of enterprises are doing in the U.S.," Christman said. "Most enterprises here that want to migrate to IPv6 have a service provider that doesn't provide [native] IPv6 yet. So they can upgrade their LAN and then tunnel IPv6 traffic over IPv4...This is a service we provide."
NTT said it saved money by running IPTV over IPv6 vs. IPv4, but it wouldn't provide details.
"The simplified, hierarchical network configuration in IPv6 saved NTT money in the capital it cost to build the NGN and the operational expenses to manage it," Christman said.
NTT says Japanese consumers find Hikari-TV easy to configure; they either push a button on their remote controls to enable the service if their TV supports IPv6 or it is enabled on their set-top boxes.
"IPv6 is invisible to the consumer," Christman said.
With Hikari-TV, NTT found "there weren't major technical hurdles to IPv6, and there were great short-term and long-term benefits of deploying IPTV based on IPv6."
NTT's U.S. subsidiary, NTT America, will discuss Hikari-TV on Jan. 10 at a panel discussion entitled "Planning for an IPv6 World in 2010" being held during the Consumer Electronics Show 2009 in Las Vegas.
NTT America officials said this panel discussion will be the first time NTT executives have described the IPv6-based Hikari-TV service in English. Previous communications were available in Japanese only.