Next Generation Networking
Encyclopedia
Next-generation network (NGN) is a broad term used to describe key architectural evolutions in telecommunication
core
and access network
s. 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 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 toward NGN.
, the definition is:
From a practical perspective, NGN involves three main architectural changes that need to be looked at separately:
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
).
(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. So really SIP is a useful tool for the "local loop" and H.323 is like the "fiber backbone". 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
).
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 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 Wave 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 Agreement
s (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 a NGN network in a network transformation program called all-IP — this is another loose term for NGN that is increasingly used. 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 Israel, Bezeq
announced in a June 2009 press release the move to NGN in selected areas. The service will allow enhanced services to phone subscribers as well as upgraded speed capabilities for ADSL users (up to 100Mbit/s DL, 1000kbit/s UL).
In Canada, upstart Wind Mobile
owned by Globalive is deploying an all-ip wireless backbone for its mobile phone service.
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
core
Core network
A core network, or network core, is the central part of a telecommunication network that provides various services to customers who are connected by the access network. One of the main functions is to route telephone calls across the PSTN....
and access network
Access network
An access network is that part of a telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the core network, which connects local providers to each other...
s. 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 packets, similar to those used on the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
. NGNs are commonly built around the Internet Protocol
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
, and therefore the term all IP is also sometimes used to describe the transformation toward NGN.
Description
According to ITU-TITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
, the definition is:
- A next-generation network (NGN) is a packet-based networkComputer networkA computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
which can provide services including Telecommunication Services and able to make use of multiple broadbandBroadbandThe term broadband refers to a telecommunications signal or device of greater bandwidth, in some sense, than another standard or usual signal or device . Different criteria for "broad" have been applied in different contexts and at different times...
, quality of ServiceQuality of serviceThe quality of service refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements...
-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.25X.25X.25 is an ITU-T standard protocol suite for packet switched wide area network communication. An X.25 WAN consists of packet-switching exchange nodes as the networking hardware, and leased lines, Plain old telephone service connections or ISDN connections as physical links...
, frame relayFrame relayFrame Relay is a standardized wide area network technology that specifies the physical and logical link layers of digital telecommunications channels using a packet switching methodology...
(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 networkAccess networkAn access network is that part of a telecommunications network which connects subscribers to their immediate service provider. It is contrasted with the core network, which connects local providers to each other...
, 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 PacketCablePacketCablePacketCable is an industry consortium founded by CableLabs with the goal of defining standards for the cable television modem access industry....
standards that provide VoIP and SIPSession Initiation ProtocolThe Session Initiation Protocol is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol . The protocol can be used for creating, modifying and terminating two-party or multiparty sessions...
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
Set-top box
A set-top box or set-top unit is an information appliance device that generally contains a tuner and connects to a television set and an external source of signal, turning the signal into content which is then displayed on the television screen or other display device.-History:Before the...
).
Underlying technology components
Next-generation networks are based on Internet technologies including Internet ProtocolInternet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
(IP) and multiprotocol label switching
Multiprotocol Label Switching
Multiprotocol Label Switching is a mechanism in high-performance telecommunications networks that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table. The labels identify virtual links between...
(MPLS). At the application level, Session Initiation Protocol
Session Initiation Protocol
The Session Initiation Protocol is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol . The protocol can be used for creating, modifying and terminating two-party or multiparty sessions...
(SIP) seems to be taking over from ITU-T H.323
H.323
H.323 is a recommendation from the ITU Telecommunication Standardization Sector that defines the protocols to provide audio-visual communication sessions on any packet network...
.
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
Network address translation
In computer networking, network address translation is the process of modifying IP address information in IP packet headers while in transit across a traffic routing device....
(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. So really SIP is a useful tool for the "local loop" and H.323 is like the "fiber backbone". 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
IP Multimedia Subsystem
The IP Multimedia Subsystem or IP Multimedia Core Network Subsystem is an architectural framework for delivering Internet Protocol multimedia services. It was originally designed by the wireless standards body 3rd Generation Partnership Project , as a part of the vision for evolving mobile...
(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
Softswitch
A softswitch is a central device in a telecommunications network which connects telephone calls from one phone line to another, typically via the internet, entirely by means of software running on a general-purpose computer system...
– 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
H.323 Gatekeeper
An H.323 Gatekeeper serves the purpose of Call Admission Control and translation services from E.164 IDs to IP addresses in an H.323 telephony network. Gatekeepers can be combined with a gateway function to proxy H.323 calls and are sometimes referred to as Session Border Controllers...
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
SS7
SS-7 can stand for:* Signaling System #7, a set of telephone signaling protocols.* The R-16 missile, with NATO reporting name SS-7 Saddler.* China Railways SS7, an electric locomotive model in China.* Super Socket 7, a chip socket introduced by AMD...
) to the packet-based one (IP
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
). 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
Media Gateway Controller
A Media Gateway Controller is a system used in certain Voice over IPtelephony architectures. An MGC controls a number of dumb terminals, the Media Gateways...
(MGC).
A Call Agent is a general name for devices/systems controlling calls.
The IP Multimedia Subsystem
IP Multimedia Subsystem
The IP Multimedia Subsystem or IP Multimedia Core Network Subsystem is an architectural framework for delivering Internet Protocol multimedia services. It was originally designed by the wireless standards body 3rd Generation Partnership Project , as a part of the vision for evolving mobile...
(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
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...
).
Implementations
In the UK another popular acronym was introduced by BT (British Telecom)BT Group
BT Group plc is a global telecommunications services company headquartered in London, United Kingdom. It is one of the largest telecommunications services companies in the world and has operations in more than 170 countries. Through its BT Global Services division it is a major supplier of...
as 21CN
BT 21CN
The 21st Century Network programme is the network transformation project of the UK telecommunications company BT Group plc for data and voice. It had been intended to move BT's telephone network from the present AXE/System X Public Switched Telephone Network to an Internet Protocol system...
(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 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 Wave 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 Agreement
Service Level Agreement
A service-level agreement is a part of a service contract where the level of service is formally defined. In practice, the term SLA is sometimes used to refer to the contracted delivery time or performance...
s (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
KPN
KPN is a Dutch landline and mobile telecommunications company, including both 2G and 3G mobile operations...
is developing a NGN network in a network transformation program called all-IP — this is another loose term for NGN that is increasingly used. 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)
Bulgarian Telecommunications Company
VIVACOM , previously named Bulgarian Telecommunications company is the largest telecommunications company in Bulgaria and a former state-owned monopoly...
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 Israel, Bezeq
Bezeq
Bezeq, the Israeli company for communications, is a telecommunications provider in Israel.Until the mid-first decade of the 21st century when it was owned by the Israeli government, Bezeq had a monopoly on landline telephony and Internet access infrastructure...
announced in a June 2009 press release the move to NGN in selected areas. The service will allow enhanced services to phone subscribers as well as upgraded speed capabilities for ADSL users (up to 100Mbit/s DL, 1000kbit/s UL).
In Canada, upstart Wind Mobile
Wind Mobile
Wind Mobile is a Canadian wireless telecommunications provider operated by Globalive Communications Corporation. The company initially launched mobile data and voice services in Toronto on December 16, 2009 and two days later in Calgary...
owned by Globalive is deploying an all-ip wireless backbone for its mobile phone service.
See also
- Active network
- Computer networkComputer networkA computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
- Fixed-Mobile Convergence Alliance (FMCA)
- Flat IPFlat IPFlat IP architecture provides a way to identify devices using symbolic names, unlike the hierarchical architecture such as that used in "normal" IP addresses...
- Mobile VoIPMobile VoIPMobile VoIP or simply mVoIP is an extension of mobility to a Voice over IP network. Two types of communication are generally supported: cordless/DECT/PCS protocols for short range or campus communications where all base stations are linked into the same LAN, and wider area communications using...
- IP Multimedia SubsystemIP Multimedia SubsystemThe IP Multimedia Subsystem or IP Multimedia Core Network Subsystem is an architectural framework for delivering Internet Protocol multimedia services. It was originally designed by the wireless standards body 3rd Generation Partnership Project , as a part of the vision for evolving mobile...
(IMS) - Nanoscale networkNanoscale networkA nanonetwork or nanoscale network is a set of interconnected nanomachines, i.e., devices in the order of a few hundred nanometers or a few micrometers at most, which are able to perform only very simple tasks such as computing, data storing, sensing and actuation...
- Network convergenceNetwork ConvergenceNetwork convergence refers to the provision of telephone, video and data communication services within a single network. In other words, one pipe is used to deliver all forms of communication services. The process of Network Convergence is primarily driven by development of technology and demand...
- Next-generation network services
- Telecom transformationTelecom TransformationTelecom Transformation, or IP Transformation, is a term that describes the evolution of the telecommunications industry from a capital-intensive, technology-focused model to a user-centric service-delivery model. The reasons for this transformation vary in different parts of the world, but some...
External links
- ETSI TISPAN website
- ECMA TR/91 "Enterprise Communication in Next Generation Corporate Networks (NGCN) involving Public Next Generation Networks (NGN) (Ecma-International, December 2005)" (also ISO/IEC DTR 26905 and ETSI TR 102 478)
- ITU-T Focus Group on Next Generation Networks (FGNGN)
- ITU-T NGN Management Focus Group
- NGN enabled label
- NGN Forum