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Wikipedia
The next-generation network (NGN) is a body of key architectural changes in telecommunication core and access networks. The general idea behind the NGN is that one network transports all information and services (voice, data, and all sorts of media such as video) by encapsulating these into IP packets, similar to those used on the Internet. NGNs are commonly built around the Internet Protocol, and therefore the term all IP is also sometimes used to describe the transformation of formerly telephone-centric networks toward NGN.
NGN is a different concept from Future Internet, which is more focused on the evolution of Internet in terms of the variety and interactions of services offered.
According to ITU-T, the definition is:
- A next-generation network (NGN) is a packet-based network which can provide services including Telecommunication Services and is able to make use of multiple broadband, quality of service-enabled transport technologies and in which service-related functions are independent from underlying transport-related technologies. It offers unrestricted access by users to different service providers. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users.
From a practical perspective, NGN involves three main architectural changes that need to be looked at separately:
- In the core network, NGN implies a consolidation of several (dedicated or overlay) transport networks each historically built for a different service into one core transport network (often based on IP and Ethernet). It implies amongst others the migration of voice from a circuit-switched architecture (PSTN) to VoIP, and also migration of legacy services such as X.25, frame relay (either commercial migration of the customer to a new service like IP VPN, or technical emigration by emulation of the “legacy service” on the NGN).
- In the wired access network, NGN implies the migration from the dual system of legacy voice next to xDSL setup in local exchanges to a converged setup in which the DSLAMs integrate voice ports or VoIP, making it possible to remove the voice switching infrastructure from the exchange.
- In the cable access network, NGN convergence implies migration of constant bit rate voice to CableLabs PacketCable standards that provide VoIP and SIP services. Both services ride over DOCSIS as the cable data layer standard.
In an NGN, there is a more defined separation between the transport (connectivity) portion of the network and the services that run on top of that transport. This means that whenever a provider wants to enable a new service, they can do so by defining it directly at the service layer without considering the transport layer – i.e. services are independent of transport details. Increasingly applications, including voice, tend to be independent of the access network (de-layering of network and applications) and will reside more on end-user devices (phone, PC, set-top box).
Next-generation networks are based on Internet technologies including Internet Protocol (IP) and multiprotocol label switching (MPLS). At the application level, Session Initiation Protocol (SIP) seems to be taking over from ITU-T H.323.
Initially H.323 was the most popular protocol, though its popularity decreased in the “local loop” due to its original poor traversal of network address translation (NAT) and firewalls. For this reason as domestic VoIP services have been developed, SIP has been more widely adopted. However, in voice networks where everything is under the control of the network operator or telco, many of the largest carriers use H.323 as the protocol of choice in their core backbones. With the most recent changes introduced for H.323, it is now possible for H.323 devices to easily and consistently traverse NAT and firewall devices, opening up the possibility that H.323 may again be looked upon more favorably in cases where such devices encumbered its use previously. Nonetheless, most of the telcos are extensively researching and supporting IP Multimedia Subsystem (IMS), which gives SIP a major chance of being the most widely adopted protocol.
For voice applications one of the most important devices in NGN is a Softswitch – a programmable device that controls Voice over IP (VoIP) calls. It enables correct integration of different protocols within NGN. The most important function of the Softswitch is creating the interface to the existing telephone network, PSTN, through Signalling Gateways and Media Gateways. However, the Softswitch as a term may be defined differently by the different equipment manufacturers and have somewhat different functions.
One may quite often find the term Gatekeeper in NGN literature. This was originally a VoIP device, which converted (using gateways) voice and data from their analog or digital switched-circuit form (PSTN, SS7) to the packet-based one (IP). It controlled one or more gateways. As soon as this kind of device started using the Media Gateway Control Protocol, the name was changed to Media Gateway Controller (MGC).
A Call Agent is a general name for devices/systems controlling calls.
The IP Multimedia Subsystem (IMS) is a standardised NGN architecture for an Internet media-services capability defined by the European Telecommunications Standards Institute (ETSI) and the 3rd Generation Partnership Project (3GPP).
In the UK, another popular acronym was introduced by BT (British Telecom) as 21CN (21st Century Networks, sometimes mistakenly quoted as C21N) — this is another loose term for NGN and denotes BT’s initiative to deploy and operate NGN switches and networks in the period 2006–2008 (the aim being by 2008 BT to have only all-IP switches in their network). The concept was abandoned, however, in favor of maintaining current-generation equipment.
The first company in the UK to roll out a NGN was THUS plc which started deployment back in 1999. THUS’ NGN contains 10,600 km of fibre optic cable with more than 190 points of presence throughout the UK. The core optical network uses dense wavelength-division multiplexing (DWDM) technology to provide scalability to many hundreds of gigabits per second of bandwidth, in line with growth demand. On top of this, the THUS backbone network uses MPLS technology to deliver the highest possible performance. IP/MPLS-based services carry voice, video and data traffic across a converged infrastructure, potentially allowing organisations to enjoy lower infrastructure costs, as well as added flexibility and functionality. Traffic can be prioritised with Classes of Service, coupled with Service Level Agreements (SLAs) that underpin quality of service performance guarantees. The THUS NGN accommodates seven Classes of Service, four of which are currently offered on MPLS IP VPN.
In the Netherlands, KPN is developing an NGN in a network transformation program called all-IP. Next Generation Networks also extends into the messaging domain and in Ireland, Openmind Networks has designed, built and deployed Traffic Control to handle the demands and requirements of all IP networks.
In Bulgaria, BTC (Bulgarian Telecommunications Company) has implemented the NGN as underlying network of its telco services on a large-scale project in 2004. The inherent flexibility and scalability of the new core network approach resulted in an unprecedented rise of classical services deployment as POTS/ISDN, Centrex, ADSL, VPN, as well as implementation of higher bandwidths for the Metro and Long-distance Ethernet / VPN services, cross-national transits and WebTV/IPTV application.
In February 2014, Deutsche Telekom revealed that its subsidiary Makedonski Telekom had become the first European incumbent to convert its PSTN infrastructure to an all IP network. It took just over two years for all 290,000 fixed lines to be migrated onto the new platform. The capital investment worth 14 million euros makes Macedonia the first country in the South-East Europe whose network will be fully based on Internet protocol.
In Canada, startup Wind Mobile owned by Globalive is deploying an all-ip wireless backbone for its mobile phone service.
In mid 2005, China Telecom announced its commercial roll-out of China Telecom’s Next Generation Carrying Network, or CN2, using Internet Protocol Next-Generation Network (IP NGN) architecture. Its IPv6-capable backbone network leverages softswitches (the control layer) and protocols like DiffServ and MPLS, which boosts performance of its bearer layer. The MPLS-optimized architecture also enables Frame Relay and ATM traffic to be transported over a Layer 2 VPN, which supports both legacy traffic and new IP services over a single IP/MPLS network.
Web 2.0 (also known as participative (or participatory) web and social web) refers to websites that emphasize user-generated content, ease of use, participatory culture and interoperability (i.e., compatibility with other products, systems, and devices) for end users.
The term was coined by Darcy DiNucci in 1999 and later popularized by Tim O’Reilly and Dale Dougherty at the first Web 2.0 Conference in late 2004. Although the term mimics the numbering of software versions, it does not denote a formal change in the nature of the World Wide Web, but merely describes a general change that occurred during this period as interactive websites proliferated and came to overshadow the older, more static websites of the original Web.
A Web 2.0 website allows users to interact and collaborate with each other through social media dialogue as creators of user-generated content in a virtual community. This contrasts the first generation of Web 1.0-era websites where people were limited to viewing content in a passive manner. Examples of Web 2.0 features include social networking sites or social media sites (e.g., Facebook), blogs, wikis, folksonomies (“tagging” keywords on websites and links), video sharing sites (e.g., YouTube), image sharing sites (e.g., Flickr), hosted services, Web applications (“apps”), collaborative consumption platforms, and mashup applications.
Whether Web 2.0 is substantially different from prior Web technologies has been challenged by World Wide Web inventor Tim Berners-Lee, who describes the term as jargon. His original vision of the Web was “a collaborative medium, a place where we [could] all meet and read and write”. On the other hand, the term Semantic Web (sometimes referred to as Web 3.0) was coined by Berners-Lee to refer to a web of content where the meaning can be processed by machines.
Web 1.0 is a retronym referring to the first stage of the World Wide Web’s evolution, from roughly 1991 to 2004. According to Graham Cormode and Balachander Krishnamurthy, “content creators were few in Web 1.0 with the vast majority of users simply acting as consumers of content”. Personal web pages were common, consisting mainly of static pages hosted on ISP-run web servers, or on free web hosting services such as Tripod and the now-defunct GeoCities. With Web 2.0, it became common for average web users to have social-networking profiles (on sites such as Myspace and Facebook) and personal blogs (sites like Blogger, Tumblr and LiveJournal) through either a low-cost web hosting service or through a dedicated host. In general, content was generated dynamically, allowing readers to comment directly on pages in a way that was not common previously.
Some Web 2.0 capabilities were present in the days of Web 1.0, but were implemented differently. For example, a Web 1.0 site may have had a guestbook page for visitor comments, instead of a comment section at the end of each page (typical of Web 2.0). During Web 1.0, server performance and bandwidth had to be considered—lengthy comment threads on multiple pages could potentially slow down an entire site. Terry Flew, in his third edition of New Media, described the differences between Web 1.0 and Web 2.0 as a
“move from personal websites to blogs and blog site aggregation, from publishing to participation, from web content as the outcome of large up-front investment to an ongoing and interactive process, and from content management systems to links based on “tagging” website content using keywords (folksonomy).”
Flew believed these factors formed the trends that resulted in the onset of the Web 2.0 “craze”.