While it is likely that initially 3DTV will be delivered by traditional transport mechanisms, including DVB over DTH systems, recently some research efforts have been focused on delivery (streaming) of 3DTV using IP. IP can be used for IPTV systems or over an IP shared infrastructure, whether a private network (here shared with other applications) or over the Internet (here shared with a multitude of other users and applications) (some studies have also been undertaken of late on the capabilities of DVB-H to broadcast stereo-video streams.) However, it seems that the focus so far has been on IPv4; the industry is encouraged to assess the capabilities of IPv6. While this topic is partially tangential to a core 3DTV discussion, the abundant literature on proposals for packet-based delivery of future 3DTV (including but not limited to Refs [4–13]) makes the issue relevant. IPv6, when used with header compression, is expected to be a very useful technology to support IPTV in the future in general and 3DTV in particular. For a general discussion of IPTV and DVB-H, the reader may refer to Ref. [14] among other references.
IPv6 was defined in the mid-1990s in IETF Request for Comments (RFC) 2460 “Internet Protocol, Version 6 (IPv6) Specification” and a host of other more recent RFCs, is an “improved, streamlined, successor version” of IPv4.4 Because of market pull from the Office of Management and Budget’s mandate that 24 major federal agencies in the US Government (USG) be IPv6-ready by June 30, 2008, and because of market pull from European and Asian institutions, IPv6 is expected to see gradual deployment from this point forward and in the coming decade. With IPv6 already gaining momentum globally, with major interest and activity in Europe and Asia and also some traction in the United States; the expectation is that in the next few years a (slow) transition to this new protocol will occur worldwide. An IP-based infrastructure has now become the ubiquitous underlying architecture for commercial-, institutional-, and USG/Other (non-US)
Government (OG) communications and services functions. IPv6 is expected to be the next step in the industry’s evolution in the past 50 years from analog, to digital, to packet, to broadband. As an example of IPv6 deployment underway, Europe has set the objective to widely implement IPv6 by 2010; the goal is that at least 25% of users should be able to connect to the IPv6 Internet and to access their most important content and service providers without noticing a major difference when compared to IPv4.
IPv6 offers the potential of achieving increased scalability, reachability, endto- end interworking, QoS, and commercial-grade robustness for data communication, mobile connectivity, and for VoIP/triple-play networks. The current version of the IP, IPv4, has been in use successfully for almost 30 years and poses some challenges in supporting emerging demands for address space cardinality, high-density mobility, multimedia, and strong security. This is particularly true in developing domestic and defense department applications utilizing peer-to-peer networking. IPv6 is an improved version of IP that is designed to coexist with IPv4 while providing better internetworking capabilities than IPv4 [14–17].
When the current version of IPv4 was conceived in the mid-1970s and defined soon thereafter (1981), it provided just over 4 billion addresses; that is not enough to provide each person on the planet with one address without even considering the myriad of other devices and device modules needing addressability (such as but not limited to over 3 billion cellphones). Additionally, 74% of IPv4 have been assigned to North American organizations. The goal of developers is to be able to assign IP addresses to a new class of Internet-capable devices: mobile phones, car navigation systems, home appliances, industrial equipment, and other devices (such as sensors and Body-Area-Network medical devices). All of these devices can then be linked together, constantly communicating, even in wireless mode. Projections show that the current generation of the Internet will “run out of space” in the near future (2010/2011) if IPv6 is not adopted around the world. IPv6 is an essential technology for ambient intelligence and will be a key driver for a multitude of new, innovative mobile/wireless applications and services [18].
IPv6 was initially developed in the early 1990s because of the anticipated need for more end system addresses based on anticipated Internet growth, encompassing mobile phone deployment, smart home appliances, and billions of new users in developing countries (e.g., in China and India). New technologies and applications such as VoIP, “always-on access” (e.g., DSL and cable), Ethernet-tothe- home, converged networks, and evolving ubiquitous computing applications will continue to drive this need even more in the next few years [19].
IPv6 features, in comparison with IPv4, include the following [20]:
- Expanded Addressing Capabilities: IPv6 increases the IP address size from 32 bits to 128 bits to support more levels in the addressing hierarchy, a much greater number of addressable nodes, and simpler autoconfiguration of addresses. The scalability of multicast routing is improved by adding a “scope” field to multicast addresses. A new type of address called an “anycast address” is also defined to be used to send a packet to any one of a group of nodes.
- Header Format Simplification: Some IPv4 header fields have been dropped or made optional, to reduce the common-case processing cost of packet handling and to limit the bandwidth cost of the IPv6 header.
- Authentication and Privacy Capabilities: In IPv6, security is built-in as part of the protocol suite: extensions to support authentication, data integrity (encryption), and (optional) data confidentiality are specified for IPv6. The security features of IPv6 are described in the Security Architecture for the Internet Protocol RFC 2401 [21], along with RFC 2402 [22] and RFC2406 [23]; Internet Protocol Security (IPsec) defined in these RFCs is required (mandatory). IPsec is a set of protocols and related mechanisms that supports confidentiality and integrity. (IPsec was originally developed as part of the IPv6 specification, but due to the need for security in the IPv4 environment, it has also been adapted for IPv4).
- Flow Labeling Capability: A new feature is added to enable the labeling of packets belonging to particular traffic “flows” for which the sender requests special handling, such as non-default quality of service or “real-time” service. Services such as VoIP and IP-based entertainment video delivery (IPTV) is becoming broadly deployed and flow labeling, especially in the network core, can be very beneficial.
- Improved Support for Extensions and Options: Changes in the way IP header options are encoded allows for more efficient forwarding, less stringent limits on the length of options, and greater flexibility for introducing new options in the future.
End systems (such as PCs, servers), network elements (customer-owned and/or carrier-owned) and (perhaps) applications need to be IPv6-aware to communicate in the IPv6 environment. IPv6 has been enabled on many computing platforms. At this juncture, many operating systems come with IPv6 enabled by default; IPv6-ready Operating Systems (OS) include but are not limited to Mac OS X,
OpenBSD, NetBSD, FreeBSD, Linux, Windows Vista, Windows XP (Service Pack 2), Windows 2003 Server, and Windows 2008 Server. Java began supporting IPv6 with J2SE 1.4 (in 2002) on Solaris and Linux. Support for IPv6 on Windows was added with J2SE 1.5. Other languages, such as C and C++ also support IPv6. At this time the number of applications with native IPv6 support is significant given that most important networking applications provide native IPv6 support. Hardware vendors including Apple Computer, Cisco Systems,
HP, Hitachi, IBM, and Microsoft, support IPv6. One should note that IPv6 was designed with security in mind, but at the current time its implementation and deployment are (much) less mature than is the case for IPv4. When IPv4 was developed in the early 1980s, security was not a consideration; now a number of mechanisms have been added to address security considerations to IP. When IPv6 was developed in the early-to-mid 1990s, security was a consideration; hence, a number of mechanisms have been built-in into the protocol from the get-go to furnish security capabilities to IP.
A presentation delivered during an open session at the July 2007 ICANN Public Meeting in San Juan, Puerto Rico made note of the accelerated depletion rate of IPv4 addresses and the growing difficulties the Regional Internet Registries (RIRs) are experiencing in allocating contiguous address blocks of sufficient size to service providers. Furthermore, the fragmentation in the IPv4 address space
is taxing and stressing the global routing fabric and the near-term expectation is that the RIRs will impose more restrictive IPv4 allocation policies and promote a rapid adoption of IPv6 addresses [24]. The IPv4 address space is expected to run out by 2012.