Next Generation Network

Next Generation Network ( NGN), and Next Generation Access Network ( NGA ) referred to in the telecommunications, networking, etc., which replaces traditional circuit -switched telecommunications networks, such as telephone networks, cable television networks, mobile networks by a single packet-switched network infrastructure and architecture, and the older telecommunications networks compatible. The term NGN / NGA is also ( simplistic ) as a slogan for the current shift from the existing telecommunications networks to Internet Protocol technology (IP ) is used as the Internet protocol is the dominant choice for the implementation of packet-switching networks.

The advantage is the convergence. This is one of the essential characteristics of NGN various network functions such as transportation, service and the control function can be realized (eg signaling) on different (logical) network levels.

Critics of NGNs a threat to net neutrality. In particular, the planned introduction of the defined end-to- end quality of service (QoS ) and the associated possibility of data streams targeted " slowing down " or even shut out, is noted here.

• 2.1 Definition of the ITU
• 2.2 The concept of ETSI working group TIPHON
• 2.3 The IMS 3GPP
• 2.4 The concept of ETSI TISPAN working group 2.4.1 Transport layer
• 2.4.2 Service layer

• 4.1 Operating costs

Background

Motivation

Due to the increasing cost pressure in the telecommunications market and the decline in prices for voice services, the service providers and network operators are forced to seek new approaches to economic and efficient provision of telecommunications services, and operation of telecommunications networks. So far, the telecommunications market has been dominated by traditional telephony providers. However, it is observed an increasing convergence of services and networks. This also urge classic portal providers such as Google, Yahoo, MSN or even cable operators on this market. The increasing availability of telephone services using IP telephony ( VoIP) is just one example. As part of this convergence takes in retail revenues, the value contribution of the network deployment in favor of services from; the value chain of the telecommunications market are changing. The established network operators therefore are forced to seek cost savings and to rethink their business models.

The traditional telecommunications infrastructure is built heterogeneous. Fixed telephony and data transmission can be realized with different technologies. There are direct dependencies between services and the technology used, whereby the introduction of new services is through adjustments to the hardware a very costly and lengthy process. A unified network infrastructure, which can be used as a platform for the provision of all services would save costs and time. Additionally, the limitation to a single system technology a big savings in terms of costs for maintenance, modification and procurement as well as the reduction of technical sites and areas. As a fundamental way the transition from the previous circuit-switched networks to packet- switched networks is seen using the Internet Protocol.

It should also be noted that a change in the infrastructure of packet switching can not occur abruptly, but that the existing telephone networks and network access with appropriate switched- network devices over a longer period in parallel with the new network structures must be operated. So a trouble-free migration process must be ensured. The new network infrastructure must therefore allow a PSTN / ISDN simulation or emulation.

Against this background, sees the need to develop a comprehensive network architecture that provides control mechanisms, by which the network resources according to the requirements of the services and the number of users can be managed efficiently and controlled. The aim of the NGN development is to meet these requirements.

Historical development

The first NGN specifications for the European region were carried out in ETSI Project TIPHON ( Telecommunications and Internet Protocol Harmonization Over Networks). By combining this project with the ETSI TC SPAN ( Services and Protocols Technical Committee for Advanced Networks) then the ETSI TC TISPAN ( Telecoms & Internet converged Services & Protocols for Advanced Networks ), that are within the still the processing standards for NGN supervised by ETSI.

ETSI TC TISPAN in the work done against the background of the development of concepts for the migration from PSTN / ISDN to packet -switched networks. It is specified an NGN can turn on and replace the PSTN and ISDN. In this case, all system components are provided to implement in particular voice communication service in a NGN. There are specified by the TISPAN working group to help network operators to develop migration strategies to fall back on standardized components can Protocols and mechanisms.

In addition, even the 3rd Generation Partnership Project (3GPP ), which is developed from an NGN UMTS out and thus promoted by the mobile operators exist. 3GPP has developed the core specification of the IP Multimedia Subsystem (IMS) based on IP technology. Both groups, ETSI TC TISPAN and 3GPP, aim for an implementation of NGN based on IMS. This ETSI TISPAN and 3GPP are working closely together to avoid a divergence of the IMS specifications.

Parallel within the ITU began similar work in 1995 with the Project Global Information Infrastructure ( GII ), which then led to the specification of the ITU-T NGN. The ITU-T approach is an overarching model for long-term and complete replacement of circuit- through packet-switched networks with a focus on the definition of the basic features and architecture, while the work at ETSI have their focus more on the development of practical implementations. ETSI TISPAN tries to ensure the compatibility of ITU -T and its own approach through a close cooperation with ITU -T.

Definition and specification

Definition of the ITU

The ITU- T defines an NGN in ITU- T Recommendation Y.2001 as follows ( translation from English ):

" A next-generation network (NGN ) is a packet-switched telecommunication network that provides telecommunications services, uses many broadband, QoS- enabled transport technologies and class in which service-related functions are independent of the transport technologies used. It provides users with unlimited access to networks to competing service providers and / or services of their choice. It supports the general mobility, which enables consistent and ubiquitous provision of services to the users. "

The concept of general mobility plays a fundamental role in the NGN and in ITU- T Recommendation Y.2001 therefore more precisely defined ( translation from English ):

" The ability of the user or other mobile devices to communicate and access to telecommunications services, regardless of the change in their location or technical environment. The degree of service availability may depend on various factors, including the characteristics of the access network, the performance contracts between the " home network operator" of the user and those of the visited " network operator " (if applicable ), etc.. Mobility includes the ability of telecommunication with or without continuity of services (service continuity ). "

Furthermore, lists the ITU -T Recommendation Y.2001, the following 14 basic features that must be met in order for a telecommunication network can be regarded as NGN:

The concept of ETSI working group TIPHON

This ETSI working group was established in 1997 and has since been discontinued in favor of the ETSI TISPAN AG. The concept consists of the following main components:

• Media gateways that connect the individual networks physically and ensure the transmission of information - including A necessary format and data conversion, and
• Softswitches, which the media gateway control and, for example, connections on all network boundaries to assemble and disassemble.

New services in an NGN are also referred to as NGS (Next Generation Services). Provided these services by the so-called Service Delivery Platform (SDP ).

The IMS 3GPP

IMS is in the European region by the 3GPP, an association of operators and manufacturers in the field of mobile communications have been developed. With Release 5 of its " Technical Recommendations ( TR) " on " all IP" concept is introduced.

The concept consists of three layers, that is, " Transport Layer " of the ITU approach thereby split into " Transport Layer " and " IMS Layer". The functionality is distributed as follows:

• The transport layer includes the gateways and integrates the access networks
• The IMS layer includes the "Call Control" function ( CSCF), and control functions for the gateways
• The service layer contains the HSS ( database) and AS ( Application Server)

A detailed description and sources located in the IP multimedia subsystem.

The concept of ETSI TISPAN working group

The ETSI TISPAN NGN is specified in Release 2. The concept takes IMS to the starting point ( " Core IMS " ) and not integrated mobile- specific forms of access. Are mentioned in particular:

• "Fixed Access" (SIP and classic telephony)
• "Cable Access" (access from cable TV networks )
• " Mobile Access " ( mobile)
• " Broadband Wireless Access" (WLAN, WIMAX )

In the ETSI specification ES 282 001 the basic architecture is defined.

ETSI distinguishes between two functional groups:

• Transport layer (transport stratum )
• Service layer ( service stratum )

The applications are here counted as service layer. It is spoken of ( logical) functions, as its technical realization is not an object of the specifications. The terms have nothing to do with the similar-sounding of the OSI model.

Transport layer

The transport layer includes the " transport processing functions", the "Network Attachment Subsystem" (NASS ) and the Resource and Admission Control Subsystem ( RACS ). The transport processing functions ( in Release 1 transfer functions called ) tie the system to the NGN -to-use networks. This includes signaling and media gateways. The NASS and RACS which contain the control functions and services of the transport layer. These include in particular the IP address management, IP - based access control (both NASS), Resource Management and NAT support (both RACS ).

Service layer

The " Core" IP Multimedia Subsystem (IMS ) is the central component of the NGN architecture. It implements a SIP IMS switch to control all SIP multimedia services. It supports the IMS based PSTN / ISDN emulation system.

The PSTN / ISDN emulation subsystem (PES ) allows to emulate PSTN or ISDN services, and thus to connect devices of classic telephony to the NGN. The PES are two approaches: the softswitch -based approach and the approach based on the IMS.

The The IPTV subsystem specifies the integration of IPTV and similar services in the NGN.

The common components are a set of functions that are shared by the above-mentioned functions of the service layer. These include in particular interfaces for database access (User Profile Server Function and Subscription Locator Function) and to access the applications ( Application Server Function ( ASF) )

For the Application Server Function ( ASF) three interfaces are defined:

• SIP Application Server ( SIP AS) for the connection of applications that dominate the SIP
• The IM- SSF application server to connect to IN applications with ETSI Core INAP or CAMEL interfaces
• OSA SCS Application Server to connect to IN applications with OSA / Parlay interfaces

ETSI TISPAN specifies no applications. Examples of applications are mentioned in the literature.

End - to-end quality of service

A general problem is caused by the simultaneous use of the same network for the transmission of voice and data. An increased traffic, the latency of voice would increase, which is perceived by the interlocutors as disturbing. The organizations involved in the definition of the NGN concept seen here measures to achieve the "broadband capability with defined end - to-end Quality of Service (QoS )" as necessary to.

See also characteristics of quality in IP telephony

Power requirements for the end user

When using a modem with router for a Next Generation Network ( NGN) and built-in analog telephone adapter may incur a substantial electrical power. As an example, the products sold by the company Arcor modems are ( Residential Gateway ( RGW )) of the manufacturer's Standard Microsystems Corporation (SMC ) are used: Refer to the nameplate is the A400 with 15 watts, the type A401 and A601 indicated with 18 watts power consumption. In POTS and ISDN lines that are connected to the network operator to an Access Gateway ( AGW), on the other hand, there is no deviating from the conventional telephone line and power requirements for the end user.

Running costs

Because of the need for the phone adapter uninterrupted operation result of example as consumption and costs for routers manufactured by Arcor

• A400 with 15 watts Power consumption: 131.4 kWh / year; 0.28 € / kWh arise € 36.79 / a Operating Costs
• A401, A601 with 18 watts Power consumption: 157.7 kWh / year; 0.28 € / kWh arise € 44.16 / a operating costs.

Criticism

Critics complain that in NGN providers of telephone service is fixedly coupled to the broadband connection again and thus VoIP providers who have developed their products so far this network neutral Internet, be excluded from the new networks. In addition, customers are largely forced to use the NGN telephony, because the hardware does not allow operators to use the telephones connected with other VoIP provider.

A major advantage of VoIP is the use of the road. Thus, VoIP customers traveling to any broadband connection worldwide via phone software or VoIP -enabled mobile phone at their local call number accessible. Since the terminal is registered in Germany, falls for phone calls to the home of the only German fare at. Next Generation Network waived this comfort and closes the nomadic use of.

Because of the open standards used by the VoIP providers SIP protocol and its opportunities will be developed around the world. This also benefits the audio quality. So allow wideband codecs now a voice quality on hi-fi level. The application is open to all customers of alternative providers. NGN users, however, can only access the operator technique, and therefore continue to call in landline quality.

Another limitation is that NGNs are focused exclusively on voice transmission and possibly fax. This are other services - such as card terminals for business - not possible. In case of failure of the power supply is in contrast to traditional telephone connections no emergency power supply.