Roadmap for NGN – The NGN-I Project

                                                    Martin Potts

                                                 Martel GmbH
                                                Bern, Switzerland

                     Tel: +41 31 994 2525, email:

                     ABSTRACT                               2.       Service Providers require:
                                                                 • a fast, open, service creation platform
The IST project “Next Generation Networks Initiative”
                                                                 • the capability to inform end-users of the services
(NGN-I) is an open forum, in which all aspects of future              that are available
telecommunication networks are being discussed. This
                                                                 •    QoS guarantees from the network regarding
paper represents the first exposure of the services and
                                                                      availability, throughput, delay, delay variation
technologies Roadmap from the project. Though initially
                                                                      (jitter), loss, and security
concentrated on technological evolution, the project has
recently started to place more emphasis on the way that
                                                                 •    the ability to adapt services according to the
                                                                      available network QoS or device type/capabilities
the actors will communicate with each other in the
future, and the types of end-user interaction. There is     3.       Network Providers require convergence (where
therefore an ongoing mapping process between the “top-               realistic) in order to maximise efficiency and
down” requirements of services, and the “bottom-up”                  minimise costs
capabilities of networking technologies.                    Even from the short list of top-level requirements above,
                                                            it can be immediately appreciated that the issue is
                 I. INTRODUCTION                            complex:
The term “Next Generation Networks” is wide-ranging           To allow new service developers to operate
and is interpreted variously by the broad variety of          independently and efficiently, requires significant
players involved in the communications business.              changes to the current switch and router control
                                                              systems of the Network Providers. The Service
However, there is general agreement that the goal of
                                                              Provider - Network Provider interface has to be well-
Next Generation Networks is to bring services to
                                                              defined and internationally agreed.
customers in a manner that is:
                                                              It is difficult to be future-proof, when the future
 1. in accordance with the trend to separate the roles of
                                                              services are unknown.
     the various stakeholders involved, eg. Service
     Providers, Network Providers and Content                 As mobile terminals become more sophisticated, the
     Providers                                                (mobile) transitioning between networks owned by
                                                              different providers mid-session (and the corresponding
 2. interoperable (seamless transition between different
                                                              charging issue) has to be solved.
     networks (at the physical layer and above) and
     different services - internationally)                    QoS may be demanded from the network or,
                                                              alternatively, accounted for by (adaptive) applications.
 3. future-proof (the easy incorporation of new services
     and network technologies)                                QoS parameters have to be agreed between Network
Further requirements are given by specific actors. eg:        The same service used on a different terminal, or
 1. End-users require:                                        transmitted over a different access network, will
   • ubiquitous mobile access                                 require different QoS values.
   • reliability from the network                             QoS on IP.
   • simplicity from the services                             Convergence in the network is essentially limited at the
   • security from both the services and the network          moment to the network layer protocol IP, and the
   • negotiable QoS                                           acceptance that if users are going to demand
                                                              increasingly multimedia applications, then the optical
   • a “one-stop-shop” for charging and billing               infrastructure will continue to extend outwards from
 the core network, via metro networks towards the                               Roadmap considers the types of functionality that future
 access …. up to the point where the demand for                                 users will demand. These generally have implications
 mobility takes preference.                                                     throughout all parts of the network. This part of the paper
 Legacy infrastructure, the economics of upgrading the                          therefore represents the “top-down” view.
 local loop, niche markets for particular technologies,
 and even the impact of regulation are also factors that                        Significant increases in Internet traffic are expected, as
 have to be taken into account.                                                 countries such as China and India become connected.
                                                                                This increase in volume is being accompanied by a
In most cases, these topics have been addressed by                              fundamental change in the nature of the traffic. The
working groups within the NGN-I project [1].                                    almost exclusively circuit switched voice traffic became
                                                                                first mixed with - and is now heavily dominated by -
This paper has 2 main purposes:                                                 packet based data traffic.
a) to emphasise the user perspective by identifying                             End users will also tend to generate more content
    some top-level future scenarios, thereby opening a                          themselves at the edge of the network. Consumer devices
    discussion about the types of communication that                            capable of producing large amount of digital content,
    users will require                                                          such as digital photo and video cameras appear on the
                                                                                market at ever decreasing prices. End users are expected
b) to analyse whether the existing technological
                                                                                to share the wealth of information and content they
    evolution is likely to be able to serve these
                                                                                create with their peers. This will again change both the
                                                                                nature of the traffic, which is currently dominated by
The top-down assessment “a)” considers the general                              web browsing, and also the currently predominantly
service trends and tries to capture the big picture, as                         passive consumption of centralised content to a more
opposed to a bottom-up approach, where an inventory of                          balanced passive consumption and content creation.
the technological details, ingredients and necessary                            Another trend influencing traffic evolution is online
components is made and systematically analysed (Figure                          entertainment, online gaming. Virtual reality games can
1).                                                                             boost network traffic significantly. They also present
                                                                                different requirements towards the networks not only in
                                 User behaviour and
                                   usage trends
                                                                                terms of bandwidth, but also in terms of transmission
       Other general                                                            delay.
       advancements                                                             Obviously, these trends, which rely on the buying power
                                       Visions &                                of the consumer and the quick adoption of new
  Evolution of core                                             Economic
and access networks                    Scenarios                trends          technologies are heavily influenced by the prosperity of
                                                                                the world economy. These technologies will almost
  Evolution of terminals                                       Business
                                                                                certainly have long reaching social impacts, also, that are
                                                                                often under-estimated and not sufficiently understood.
        Merging top-down visions/scenarios and bottom-up technical challenges
                                                                                Finally, an example for unexpected, so-called disruptive
                                                                                events that can have long reaching impact is the tragic
                                                                                terrorist attack on 11 September 2001. As a result of that,
Individual                 Architect
                           ure and
                                                                                there has been a considerable increase in public security
  aspects      ment
                                                                                and surveillance increasing the volume of the traffic on
                                                                                the networks. In the course of 15-20 years, almost
    Figure 1: Mapping of the top-down and bottom-up                             certainly there will be other disruptive events. Including
                      approaches                                                their impact into the final picture is very difficult,
                                                                                because of their unexpected nature, but they will also
   II. USER BEHAVIOUR AND USAGE TRENDS                                          shape the future in one way or another.

Though having a mainly technical basis, all of the NGN-                         Whilst the precise successful services of the future are
I working groups considered to some extent the User                             impossible to predict, surveys on user requirements from
behaviour and usage trends. The definition of “users”                           services have been conducted by many IST projects ,
differs however, depending upon whether the issue is                            consultancy companies and other organisations.
being viewed from the perspective of the vendors,                               With a fairly high degree of confidence, we can therefore
operators, network providers, or service providers. In                          expect most of the findings that are common to the
many instances, the users of a service can also be
providers of services. For example, to NGN equipment
vendors, the users are the operators and network                                1
                                                                                    For example, TRUST, NOMAD, MOBIVAS,
providers, but from a service provider perspective, the                             MOBIX, WISE, NGN-I (SMONET), SB3G cluster
users are ISPs, corporate users and common citizens. For                            (ADAMAS,     BRAHMS,   BRAIN,    DriVE,
ISPs the users are corporate users and residential end                              EMBRACE, PRODEMIS, SUITED, VIRTUOUS,
users. Depending upon the user segment addressed, user                              WIND-FLEX, WINE GLASS)
expectations and requirements of NGNs vary
The User behaviour and usage trends part of the NGN-I

surveys to be highly relevant. These indicate that users     The concept of Ambient Intelligence is one of greater
will require services to:                                    user-friendliness, more efficient services support, user-
• be more sophisticated (service interoperability), yet      empowerment, and interfaces that are embedded in all
    simple to use and secure                                 kinds of objects (clothing, buildings, vehicles,
• run on less obtrusive hardware                             packaging, products, bodies, …). Ambient Intelligence
                                                             works in a seamless, unobtrusive and often invisible way.
• be reliable, yet cost-effective
                                                             This vision is one of people benefiting from services and
• work effectively when mobile                               applications whilst supported by new technologies in the
• offer more than just Internet access                       background and intelligent user interfaces.
• enable group communication
• be transportable between networks                          The main trends for users requirements for future
• enable the same data to be available on different          services can therefore be summarised as:
    devices                                                  • more entertaining, visually attractive, life-like
• filter information                                             services
• exploit the existence of more embedded sensors             • more mobility (and flexibility to move between
• exploit communication between embedded devices
                                                             • more security
At a more specific level, (residential) end-users have       • more peer-to-peer - and group - interaction
indicated the desire for:                                    • the exploitation of Ambient Intelligence (to both add
• quick communication via short messages to friends              value to services and hide the complexity from the
    (point-point SMS -> multicasted, multimedia                  user)
• faster access to more - and more sophisticated -                        III. SERVICES ROADMAP
    information ….. and whilst they are on the move
• “personal agents” that are able to shop around for the     A strong growth area is expected to be in new mobile
    best services                                            services. By 2010, world-wide revenues for 3G services
                                                             are expected to exceed $300B annually. Because of
• when travelling: language translation, maps, yellow        large economic opportunities for mobile operators,
    pages, location based information of the city            manufacturers of portal platforms and mobile terminals,
• combined PDA and phone services                            content developers and aggregators, many research and
• sending current position information                       development activities have been intensified in the portal
• knowing the quality of a service before paying             space. We can subdivide the portals into the following
• multimedia         communications       services     for   categories:
    entertainment (gaming).        For example, the           1. Mobile Intranet/Extranet portals: that provide
    construction, organisation and governance of a virtual        secure mobile access to corporate Local Area
    parallel world                                                Networks (LANs), Virtual Private Networks
                                                                  (VPNs), and the Internet. Examples of
The business community will require more flexibility              Intranet/Extranet portal services include: corporate
(but with security) to access company resources from              e-mail, calendar, training, customer relationship
outside the office, and to communicate with colleagues,           management including selling to existing
via a variety of different devices (fixed, wireless and           customers, servicing existing customers and
mobile). They need to instantly send and receive email,           marketing to new prospective customers, corporate
retrieve information stored on corporate networks, or             vertical applications.
participate in Net meetings - regardless of location. And     2. Customised Infotainment portals: that provide
if the mobile worker moves during a session forcing a             device-independent access to personalised content
change in network, the application session should be              anywhere, anytime. Examples of infotainment
maintained, so that work can continue uninterrupted               portal services include: streaming music, short
without any reconfiguration, rebooting, or restarting of          films, m-wallet, m-shopping, and horoscopes.
the programs in use. The amounts of data to be                3. Multimedia Messaging Services portals: that offer
transferred will be more than today, but not to the level         non-real-time, multimedia messaging with always-
that will be required by residential users for gaming and         on capabilities allowing the provision of instant
other forms of entertainment.                                     messaging. Examples of these services include:
Specialised businesses (eg. space, meteorology, oil               multimedia postcard, video clips, and movie
exploration, environmental, medical, TV) will continue            trailers.
to push the network capacity to the limit.                    4. Mobile Internet portals: that offer mobile access to
                                                                  full fixed ISP services with near-wireline
With a particular focus on making sophisticated services          transmission quality and functionality. Examples of
simple to use, the IST Advisory Group (ISTAG)                     mobile Internet portal services include: browsing,
identified 4 scenarios for daily life and work, projected
for the year 2010, that highlighted a trend towards so-
called “Ambient Intelligence”.
                                                                 UMTS Forum, Report 13, Table 10

     mobile chat, m-commerce, and mobile games.              portals:
5.   Location-Based Services portals: that enable users       1. Direct access with mobile terminals when possible
     to find other people, vehicles, resources, services,     2. Access with WAP emulators (over http) when
     or machines. It also enables others to find users, as        possible
     well as enabling users to identify their own location    3. Information from the Web site of the mobile portal,
     via terminal or vehicle identification. Examples of          or from the corporate Web site, when neither of the
     LBS portal services include: emergency services,             first two options is possible
     asset tracking, navigation, and shopping
     information.                                                 IV. THE EVOLUTON OF THE NETWORK

While mobile portals are often viewed as an extension of     The Evolution of the Network part of the NGN-I
fixed Internet portals, mobile portals are faced with        Roadmap discusses the general trends taking place in the
additional challenges of content optimisation due to         Core and Access networks, with special attention to the
small form factor devices, and the necessity of delivering   optical and mobile environments. Optical technologies
that content to the mobile user–independent of the user’s    play a major role in the Core and Metro areas, whereas
location and time.                                           the exploitation of the existing copper access, and new
Three main areas that the industry is working to resolve     wireless technologies, are dominant in the access
have been identified:                                        environment. Apart from the overall characteristics of
• Portal Application Development                             these networks, aspects such as scalability and
                                                             interoperability are addressed.
• Mobile Terminals
                                                             The following implications for the networks in the way
• Portal Service Delivery Capabilities
                                                             that services will be delivered have been identified:
NGN-I reports have highlighted three major approaches        • increased use of Internet-based services
to resolve issues related to the these topics:
                                                             • increased emphasis on mobility and roaming
 1. Convergence approach works toward a globally
      accepted open standard combining mobile, Internet,     • increasing use of peer-to-peer applications
      media, and communication concerns.                     • needs for QoS, security, flexibility
 2. Market Decision approach where the most                  • IPv63 and Post IP Protocols
      dominant player or a small number of strong            • the support of services in ways that are cost effective
      players create de facto standards, driven by the           and easy to use
      sheer     volume      of     originally  proprietary
      implementations.                                       Metro and Core Network Evolution
 3. Technical Research and Development approach in           Optical Transport Networking (OTN) represents a
      which new technology will be developed. This is        natural next step in the evolution of transport
      technology that is not yet available, but necessary    networking. For evolutionary reasons, OTNs will follow
      to deliver the needed requirements.                    many of the same high-level architectures as followed by
The traditional Internet space is more concerned with the    SONET/SDH, ie. optical networks will remain
consistent packaging, delivery and presentation of           connection-oriented, multiplexed networks. The major
content across mobile and fixed devices; while those         differences will derive from the form of multiplexing
from the mobile industry are more focused on resolving       technology used: TDM for SONET/SDH vs. wavelength
the technical issues to enable data transmission on          division for OTN. To satisfy the short-term need for
historically voice-centric networks and devices. Both        capacity gain, the large-scale deployment of WDM
parties are now beginning to appreciate the need to work     point-to-point line systems will continue. As the number
together to resolve the market and technical issues          of wavelengths grows, and as the distance between
involved.                                                    terminals grows, there will be an increasing need to add
                                                             or drop wavelengths at intermediate sites. Hence,
The services and content provided by the mobile portals
                                                             flexible, reconfigurable Optical Add-Drop Multiplexers
can be divided into six main categories:
                                                             (OADMs), will become an integral part of WDM
 1. Communications and community: eg. e-mail,                networks. As more wavelengths become deployed in
      calendar and chat.                                     carrier networks, there will be an increasing demand to
 2. Information: eg. news, weather, directories.             manage capacity. In much the same way that digital
 3. Lifestyle: eg. listings of events, restaurants, movies   cross-connects emerged to manage capacity into the
      and games.                                             electrical layer, Optical cross-connects (OXCs) will
 4. Travel: eg. hotel listings, direction assistance and     emerge to manage capacity at the optical layer.
 5. Transaction: eg. banking, stock trading, purchasing
      and auctions.
 6. Others: includes information about personalisation,
      location-based services, device type, and              3
                                                                 IPv6 as a new networking protocol is addressed in
      advertising, and also about the openness of the            most of the working groups, as it increasingly
      mobile portal, billing and target group.                   appears to offer benefits for the future networking
A mixture of methods must be used regarding mobile               convergence at the IP layer, across wired and wireless

Figure 2 depicts an OTN architecture covering the Core,      PoPs or networks through the backbone. Access is
Metro, and high-capacity Access domains. Initially the       facilitated to customers through the interconnection of
need for optical-layer bandwidth management was most         the ISP’s Provider Edge (PE) IP routers with the
acute in the Core environment, but increasingly the          Customer Edge (CE) IP routers. Existing ATM and SDH
Access network at the client or server is becoming the       equipment is shown for completeness. Provider
bottleneck for data transfer. The logical mesh-based         equipment can be collocated or not with the customer
connectivity found in the core will be supported by          equipment, depending upon the distance between
means of physical topologies, including OADM-based           customer and provider premises and on the amount of
shared protection-rings, and OXC-based mesh                  traffic generated by the customer, and the tele-housing
restoration architectures. As bandwidth requirements         policies.
grow for the Metro and Access environments, OADMs                                                                IP PoP
will be used there too.                                                                                         PE Router
                                                                                                                            CE Router

                                                                                                                                                     To WDM
                                                                                                                          IP PoP                     Backbone

                                                                                                                     IP Provider
                                                                                                                     (P) Router

                                                              Customer                SDH
                                                              Premises             ATM

                                                                                                        WDM                               WDM
                                                                  IP LAN                                 WDM
                                                                                  IP PoP                                                                  IP PoP
                                                                                                  OADM RING
                                                                                                         OADM                           OADM RING
                                                                                            T            RING

                                                                                                      Metro Core                        Metro Core
                                                              IP Customer    IP Provider
                                                              Edge (CE)      Edge (PE)
                                                                             Router                                         OXC

                                                                                                                    PE Routers              Metro

                                                              T    Transponders                       IP PoP                                            CE Router

                                                                  Figure 3: Metropolitan Area IP over WDM Example
                                                             The optical WDM Metro core is usually composed of a
   Figure 2: Optical Transport Network Architecture          ring of re-configurable OADMs, while additional point-
                                                             to-point WDM links with Terminal Multiplexers can be
We expect the Core and Metro network to consist only of      considered for large customers. OADMs offer
IP- and WDM- technologies. The architecture of the next      management interfaces so that they can be remotely re-
generation network will take advantage of the provision      configured to add and drop wavelengths (optical
of an integrated IP network layer directly on top of a       channels) to the ring through the tributary cards and
WDM transport layer. The encapsulation of IP over            multiplex them in the form of optical line signal in the
WDM can be accomplished in different ways with               corresponding line cards of the ring in each direction.
simplified network stacks deploying protocols such as
                                                             In the case where there are two WDM Metro core rings,
Packet over SONET/SDH, Gigabit Ethernet or Simple
                                                             then an optical cross-connect is needed, to route
Data Link.
                                                             wavelengths from one ring to the other supporting all-
The basic guideline for the integrated IP/WDM                optical networking. Such cross-connects are the most
architecture is that WDM is considered as a backbone         expensive pieces of optical networking equipment,
technology and IP is interconnected to the WDM               capable of performing additional tasks, such as
equipment at the edges of the Core network. Such a           wavelength switching and conversion for hundreds of
network is mainly considered by Internet Service             ports in an all-optical form without O-E conversion.
Providers and in particular Competitive Operators,
                                                             The metropolitan network should extend the
deploying optical infrastructure, leased or owned, willing
                                                             transparency and the scalability of the LAN through to
to provide IP services on top of it using IP Points of
                                                             the optical core network. The IP Metro access is
Presence (PoPs).
                                                             composed of a set of PE routers interconnected via
The optical infrastructure will gradually evolve from        optical interfaces with OADMs. At the access side of the
ATM/SDH. Different topologies of WDM equipment               metropolitan network, Fast Ethernet is becoming
may be deployed in the metropolitan and backbone areas.      commonplace.
Incumbent operators could also deploy such a network,
                                                             However, a more-compatible methodology would be the
where in that case they integrate their existing ATM and
                                                             use of optical Ethernet (40-Gigabit speeds (SONET OC–
SDH infrastructure with the DWDM equipment by using
                                                             768) have already been demonstrated). Network
the WDM backbone or core to carry the ATM and SDH
                                                             operators may limit their customers to a few Mbit/s, but
                                                             the links are gigabit-capable; and someday the fees for
                                                             gigabit-scale Ethernet services will be affordable. In the
Figure 3 depicts a future ISP’s metropolitan network
                                                             meantime, the protocols and techniques for bandwidth
consisting of a WDM optical Metro core and IP Metro
                                                             segregation over shared links exist, work well, and are
access. The IP section is composed of a number of IP
                                                             used in thousands of sites. It is a simple step to run
PoPs, where customers can access the IP network
                                                             parallel optical Ethernet trunks, each on a separate
services and traffic is groomed and forwarded to other
                                                             wavelength, all multiplexed over a single fibre pair using

DWDM technology. In this way, a point-to-point
Ethernet link could have scores of 10 Gbit/s channels,
with an aggregate Ethernet bandwidth of perhaps 400
Gbit/s. Of course, this kind of network requires very
large Ethernet switches at the ends of the fibres.
The limits on optical Ethernet bandwidth may be only
the limit of fibre optic bandwidth (perhaps 25 Tbit/s per
second for the available spectrum on today’s fibre) which
is still well beyond the capabilities of today’s lasers and
electronics. However, extrapolating from recent trends
brings us to that level in only 5 or 10 years.
In the case that the router provides interfaces working in
15xx nm range for transmission and reception, there is
no need for a transponder in the OADM. The usual case,
however, is that the routers’ optical interfaces work in
1310 nm and there is a need to adapt this wavelength to                Figure 4: Access Network Technologies
the 15xx, which is done by the corresponding two-way
transponder. The transponder converts the optical signal      In the near future, residential access is expected to
of 1310 nm to electrical and back to optical.                 remain copper-based, using technologies such as xDSL
                                                              to boost the capacity of traditional copper lines.
The Wide Area Network is usually composed of a partial
                                                              However, for business offices, optical technology is
mesh-type optical WDM network. Transmission rates of
                                                              already being used to bring high bandwidth to the end-
more than 10 Gbit/s per wavelength are providing access
                                                              user, with ATM and SDH access equipment at the
to terabits of bandwidth between metropolitan areas. The
                                                              customer premises. The next step is to use WDM
power budget is generally sufficient for distances up to
                                                              technology for these environments. WDM will first be
1000km without regeneration, reshaping and retiming.
                                                              used in industrial and campus LAN environments. The
Optical Amplification is deployed either to boost the
                                                              DWDM network at the Microsoft headquarters in
aggregate multiplexed optical line signal (eg. with an
                                                              Redmond is a good example of a trial of these latest
Erbium Doped Fibre Amplifier) or to separately
                                                              technologies, which use DWDM in the enterprise
regenerate each optical channel at the corresponding
                                                              environment. This will become technically and
                                                              economically feasible due to the very large number of
                                                              wavelengths that a single fibre can carry, thus spreading
Fixed Access Network Evolution
                                                              the cost to more subscribers. Introducing more
Broadband access needs are changing very rapidly.
                                                              wavelengths per fibre can also lead to new topologies for
Content-intensive applications are driving up the need
                                                              home access by using ring or bus like structures with an
for speed. New peer-to-peer applications such as instant
                                                              add/drop port per home so that each home has its own
messaging with text, voice and - in the future - video will
push the envelope even further since they require
bidirectional data streaming.                                 Nevertheless, the point-to-point optical fibre star
                                                              structure is preferred for business customers with critical
Today, the copper-pair-based star structure, originally
                                                              security requirements. In major cities, fibre already
installed for telephony, is still dominant in most
                                                              connects most big business offices (FTTO) and some
residential areas, with ADSL widely used to boost the
                                                              residential buildings with ring or star structures. Fibre is
throughput to some hundreds of kbit/s downstream,
                                                              getting closer to small business customers and residential
depending upon the distance from the exchange, and the
                                                              customers with double star or tree-branch structures.
quality of the copper pairs.
                                                              Fibre to the cabinet (FTTCab) and fibre to the curb
The CATV network is being upgraded to support 2-way           (FTTC) are becoming more common, also fibre to the
digital transmission, and is capable of similar data flow     town (FTTT) and fibre to the village (FTTV) are
rates upstream and downstream to ADSL. Being a shared         increasingly popular.
medium, however, the instantaneous throughput
experienced is dependent upon the number of                   Wireless Access Network Evolution
simultaneous users and their usage pattern.                   The increase in mobile communications and user
Fibre is penetrating into access areas, but the dream of      expectations for diversified wireless services has led to
fibre to the home (FTTH) or desktop has yet to                the development of a variety of wireless access systems.
materialise, mainly because of the cost-sensitive nature      Considerable effort is underway to reconcile the different
of this part of the network.                                  standards, typically by using multimode terminals and
                                                              interworking devices. However, this approach does not
                                                              seem to have all the ingredients to make the multiple
                                                              existing and emerging mobile access technologies appear
                                                              to the user as a single, seamless, and homogeneous

DVB-based access networks are deployed through                • compatible with IP-based networks
satellite transmission, for Digital TV broadcasting           • scalable; and
services. Interactive services are provided through the       • distributed.
use of e.g telephone-lines for the (narrow-band) return
channels. The technology has the main characteristic to       The resource management should provide an
be a broadcast and reliable (with very low error rate) link   independent performance calibration ("tuning knobs")
supporting around 1Gbit/s in total, and thereby able to       allowing network operators to set target levels, tailored
transport hundreds of compressed TV programs. In              to user needs, on a unified IP-based access interface.
parallel, some data-based services can be carried, adding     There will be a lot of different technologies and systems
extra features around the TV programmes, such as              that will be used for the cellular communications.
electronic programme guides (EPGs) and encryption             Therefore in the future, software radio solutions will be
keys. For terrestrial transmission of digital TV, the DVB-    developed to enable dynamic reconfiguration (for all
T standard has been standardised and will be deployed in      layers) and to offer a multifrequency and multimode
the near future progressively. Its purpose is the same, but   system.
the number of carried TV programmes will be limited to        The IP protocol will be used by all types of terminals and
about 40.                                                     by all networks. The 4G terminals will be a mobile and a
Some wireless fixed broadband-access solutions have           wireless terminal with integrated Mobile IP and Cellular
also been standardised, with relatively poor success. The     IP protocols.
local multipoint distribution service (LMDS) is being         Compared to wired networks, wireless networks have
used for point-to-multipoint applications, like Internet      specific features such as loss of packets and bit rate
access and telephony. It only has a 3-mile coverage           modifications that have a significant impact on some
radius, however. The multichannel multipoint                  applications requiring a constant QoS such as video.
distribution service (MMDS) was initially used to             Adaptation of data transport to the constraints of wireless
distribute cable television service. Currently it is being    networks with techniques such as error resilience,
developed for residential Internet service. However,          scalability or joint source-channel coding is therefore
Installations have not been profitable and service delays     critical.
have been widespread. Currently, new standards are
being defined: The IEEE 802.16 (WirelessMAN)                  Home Network Evolution
standard addresses metropolitan-area networks. The            Homes contain many kinds of network technologies, for
initial standard was approved in December 2001. The           example:
Working Group is currently developing amendment
                                                              • analogue/ISDN/ADSL/CATV/Ethernet/WLAN for
802.16a to expand the scope to licensed and license-
                                                                  communicative, interactive services
exempt bands from 2 to 11 GHz. ETSI is following a
similar track for Europe.                                     • CATV, satellite links, etc.. for entertainment services
Mobile-service networks offer access from mobile              • various low speed smart devices, interconnected and
terminals when away, but it is expected that also at home         controlled by radio, fixed, infrared, … types of
these will play an important role. Various standards exist,       network.
and they vary over geographical locations. The first          Interworking and interoperability, as well as the seamless
services to be offered were voice communication using a       provision of services, independent of the underlying
digital circuit-switched 10kbit/s connection (e.g GSM).       networks is the most challenging topic yet to be
Improvements come with the packet-switched                    addressed in the Access and Home Network
connections (e.g GPRS) that will offer always-on              environments. The standards arena of Home Networks is
connections. Third generation (3G) technologies (e.g          another area, which is currently too diversified and hence
UMTS, i-Mode) will provide multi-media applications           there is a number of proprietary technologies and
(voice, data, audio and video) and nominal connection         interfaces. This is not a cost-effective solution.
capabilities will be increased to around 64 kbit/s.           In general, the home networking standards can be
A possible way forward is the development of an open          divided into two large groups: in-home networking
radio-access concept; that is, an access network which on     standards, that provide interconnectivity of devices
one hand is based on a versatile air interface, and on the    inside the home, and home-access network standards,
other hand is capable of satisfying different applications    that provide external access and services to the home via
in different radio environments, when combined with IP-       networks like cable TV, broadcast TV, phone net and
based backbone networks.                                      satellite. Additionally, there are the mobile-service
                                                              networks that provide access from mobile terminals
Besides flexibility in the air interface, such an open
                                                              when the user is away from home.
network paradigm requires a corresponding redefinition
of layers above the physical one. In order to integrate       Many in-home networking standards require cabling
heterogeneous mobile access networks, it is necessary to      between the devices. One option is to install new cabling
break the tie between mobile users and networks, and to       in the form of galvanic twisted-pair or coaxial wires, or
move towards ways of operating that are:                      optical fibres. The alternative is to use existing cabling,
                                                              such as power-lines and phone-lines.
                                                              Using existing cabling in the home is very convenient for
     DVB,                                 end-users. For in-home networking via the phone-line,
    IEEE 802.16,

HomePNA has become the de-facto standard, providing            close to the Short-Range Wireless concept. The most
up to 10 Mbit/s (100 Mbit/s is expected). For power-line       widely deployed standard in this class is Bluetooth . Its
networking, low-bandwidth control using X10 , and              capability is providing 1 Mbit/s for few connected
(high) bandwidth data transfer using CEBus and                 devices in a small network, called a piconet. Its range is
HomePlug are the most prominent ones, offering from            between 10 and 100 meters depending on the
10 kbit/s up to 14 Mbit/s.                                     transmission power. The used transmission-band for
New cabling requires an additional effort of installation,     Bluetooth lies in the 2.4 GHz ISM band (license-fee).
but has the advantage that premium-quality cabling can         The IEEE 802.15 standard is intended to go a step
be chosen, dedicated to digital data-transport at high         further. It integrates the Bluetooth standard and
rates. The IEEE-1394a standard (also called Firewire and       harmonizes it with the IEEE 802 family, such that it is IP
i.Link) defines a serial bus that allows for data transfers    and Ethernet compatible. The objectives are a high-bit
up to 400 Mbit/s over a twisted-pair cable, and extension      rate solution (IEEE 802.15.3) providing up to 20 Mbit/s,
up to 3.2 Gbit/s using fibre is underway. Similarly,           and a low bit-rate one (IEEE 802.15.4, also known as
USB defines a serial bus that allows for data transfers        ZigBee).
up to 480 Mbit/s over a twisted-pair cable, but using a                       15
                                                               The HomeRF standard, like Bluetooth, also works in
master-slave protocol instead of the peer-to-peer protocol     the 2.4 GHz ISM band. From an initial maximum data
in IEEE-1394a. Both standards support hot plug-and-            rate of 1.6 Mbit/s, it has been extended to 10 Mbit/s.
play and isochronous streaming, via centralised media          HomeRF has a range of 50 meters at this speed. It is not
access control, which are of significant importance for        interoperable with its strongest competitor, IEEE
consumer-electronics applications. The disadvantage is         802.11b, however.
that this sets a limit to the cable lengths between devices.
                                                               Wireless LANs have a broader application area: their
Another major player is the Ethernet, which has evolved        purpose is to provide a wireless connection for
via 10 Mbit/s Ethernet and 100 Mbit/s Fast Ethernet            networked devices like laptops or even handheld devices,
using twisted-pair cabling, into Gigabit Ethernet,                                                            16
                                                               not restricted to one person. The IEEE 802.11 series of
providing 1 Gbit/s using fibre. Ethernet notably does not      standards are leading in this area. Two bands are being
support isochronous streaming since it lacks centralised       considered: The IEEE 802.11b (WiFi) standard uses the
medium-access control. Also it does not support device         2.4 GHz band, and the IEEE 802.11a standard the 5 GHz
discovery (plug-and-play). It is however widely used,          band. Notably the 802.11b standard is gaining market
also because of the low cost.                                  share. Capabilities of 802.11 are to provide up to 54
Currently there is no dominant wired networking                Mbit/s over 300 meters distance. The ETSI Hiperlan2
standard for in the home, and networks are likely to be        standard has now been merged with 802.11a, giving
heterogeneous, incorporating multiple standards, both          some features such as power control and QoS.
wired and wireless.                                            In conclusion the following challenges can be seen for
As opposed to wired networks, wireless systems are far         home networks:
easier to deploy. This is due to the smaller installation      • to handle the heterogeneity, which requires bridging
effort (no new wires), and due to a lower cost of the              solutions, or a common network abstraction layer
physical infrastructure, because the transmission medium       • to support isochronous data-transfer and plug-and-
is air. However, regulation by law and associated                  play on top of Ethernet (and IP)
licensing fees may seriously affect the actual cost of the
                                                               • to solve interference and regulation issues on power-
wireless connection. Additionally, the governmental
                                                                   line and phone-line networking
regulations vary widely throughout the world. Especially
for the license-free spectrum-bands, the issue of signal       • to increase the bandwidth, to support future
interference that limits usable bandwidth has to be                application needs
solved.                                                        • to deal with governmental regulations that vary
For in-home networks, various technologies are deployed            widely throughout the world, and prevent
or being developed. Already widely deployed in Europe              interference, especially in the license-free spectrum
is the well-known DECT technology, notably for voice               bands, to ensure optimal network performance
communication. For services other than voice, new              • to minimise the power consumption for mobile
standards are emerging. With some overlap they can be              devices: since wireless networks enable mobile
divided into two categories: Wireless PANs and LANs.               applications, their success relies on the duration and
Wireless personal-area networks (PANs) typically have a            limited weight of the devices batteries. One of the
short range-of-use (10-100 meters), and are intended to            requirements driving the development of Bluetooth
set up connections between personal devices. They are              was to have low-cost, low power consumption
6                                                              • to enable the seamless integration of new devices.
7                                                                  This involves interoperability for both low level
9                                                              13
     HomePlug,                              BlueTooth,
10                                                             14
     1394 Trade Association,                  IEEE 802.15,
11                                                             15
     USB,                                        HomeRF,
12                                                             16
     DECT,                         IEEE 802.11,

   protocols (plug-and-play devices) as well as higher-        knowledge and experiences from experts, network
   level functionality.                                        providers (for example) can better plan their deployment,
                                                               and manufacturers can better understand the needs of the
        V. TECHNOLOGY DEVELOPMENT                              providers.
                                                               At the level of services, there is also much to clarify
The Individual technical aspects (including protocols)         regarding the way in which new services can be
have been covered in detail in the NGN-I working               introduced quickly and reliably.
groups. Many have been mentioned in the preceeding             At a more technical level, there is the topical issue of
chapters.                                                      how to support end-to-end QoS across concatenated
A summary of some of the key technologies for NGNs             domains that recognise different QoS schemes. Other
would have to include:                                         concerns, that are common to many players in the
• middleware and distributed systems (to enable                telecommunications marketplace are: broadband wireless
   Service Provider - Network Provider separation)             technologies, fixed/wireless integration, optics, etc.
                                                               Many of these topics are interrelated, and the
• IP: IPv6, broadband, QoS, security, mobile and
                                                               implications can only be fully appreciated when
                                                               discussed in a multi-disciplinary group.
• multi-domain network management (for seamless
   roaming and QoS support)                                    NGN-I Mission
• seamless interworking between core and access                The NGN-I project has the mission to:
   networks                                                       gather together the (global) experts in the field of
• micro and opto-electronics                                       NGN, to: predict, plan for, and shape the future of
• trust and confidence enabling tools                              networking
                                                                  provide the opportunity for discussions, in order to
• cross-media content                                              encourage the worldwide deployment of NGN.
• multi-modal and adaptive interfaces                              Topics include (but are not limited to):
• multi-lingual dialogue mode                                         emerging technologies
                                                                      legacy networks
• embedded intelligence
                                                                      convergence
                                                                      interoperability
              VI. THE NGN-I PROJECT
                                                                      regulation
The Next Generation Networks Initiative (NGN-I)                       standards
                                                                      applications
project [1] was specifically established to be an open
                                                                      services
forum, in which all aspects of future telecommunication
                                                                      business practices
networks can be discussed. Discussion groups are
                                                                  achieve consensus (where realistic). This can be
conducted through electronic means, as well as through
                                                                   beneficial in (for example) the area of standards,
workshops and conferences. The project is a catalyst for
                                                                   where competing products will lead to lower prices
collaboration. Topics for discussion are decided by the           identify new products
members. Membership is completely voluntary, meaning              understand interoperability issues
that the members should feel that they (or the projects           generally raise awareness of next generation
they are representing) can benefit from the collaboration.         networks.
Being an IST project (January 2001 - March 2003), the
administration costs associated with running this              Who can join ?
operation are paid by the Commission. During this              Participation is open for any organisation (worldwide).
timeframe, it is therefore not necessary to collect any        Membership represents a willingness to: participate in
membership fees. There is also IST funding available in        the meetings, express views, endorse outputs, contribute
the project for members that wish to lead certain              to Web discussions, input to - and comment on -
activities (see the subsections: “Roadmaps”, “Benchmark        “Roadmaps” and “Benchmark reports”, inform of
reports” and “Standards”, below).                              relevant documents/developments, etc.
                                                               As a “Thematic Network” project, organisations from
Why is such a project needed ?                                 EU / NAS states, that take over specific leading roles and
Looking at the “big picture”, global networks are              responsibilities, can be paid for their work.
becoming increasingly complex, in terms of the
technologies, the interoperability (eg. fixed/wireless, but    How does it operate ?
also with legacy networks), the services, and the              The process is to:
management.       Technical      solutions    offered     by      agree topical themes for the next 3 months, and get
manufacturers can generally be relied upon to fulfil the           these approved by the Commission
                                                                  identify the members who will be responsible for the
purpose for which they were designed, but it becomes
increasingly difficult to select the best solution for every       results
                                                                  collect the information through the members
situation, bearing in mind also evolutionary strategies
                                                                  discuss the material at cluster meetings, workshops,
and the regulatory environment. By pooling the
                                                                   conferences, and on-line

       produce visible outputs in the form of “Roadmaps”,                 products
        “Benchmark reports” and standards.                                to participate in the NGN projects
                                                                          to become embedded in a network
    •   Topic oriented:
                                                                          to gain publicity.
         Projects         Liaison     NGN-I Results
                                                                                       VII. CONCLUSIONS
           IST                                         Collective
                          -UMTS       Benchmarking
                                                                      This paper has publicised several related aspects that are
                          -3GPP          Reports
                          -EURESCOM                   Dissemination   being collated into a Roadmap for NGN. These aspects
                                                                      include the “top-down” requirements from end-users and
           Others         -IPv6
                          --etc         Standards
                                                                      services, as well as the “bottom-up” capabilities of future
                                                                      technologies. The intention is now to open the document
               Input & Feedback                                       for comment, and to refine particularly the service
                                                                      scenarios, through the contribution of both end-users and
Roadmaps                                                              service providers.
Roadmaps are descriptions of evolution paths, ideally                 The members of the NGN-I project collectively comprise
backed up by references to trial results.                             a substantial knowledge across a broad range of
                                                                      expertise, and will lead this process. New members are
Benchmark reports                                                     welcome to join the project at any time.
Benchmark reports analyse the results from projects in
the IST Programme in comparison with developments                                VII. ACKNOWLEDGEMENTS
elsewhere in Europe (eg. COST, EURESCOM), and in                      This paper is based heavily on the valued technical
the USA and Japan. If gaps are identified, then these can             contributions from the NGN-I members, who have been
be areas for future EU Programmes. Success stories will               guided professionally by the leaders of the topic working
be highlighted for wider dissemination.                               groups. The inputs have then been edited by well-
                                                                      qualified representatives of the world communications
Standards                                                             industry. The output is being co-ordinated by a core team
Standards can be a strategic tool for bringing products               of respected colleagues, and the efforts are being mainly
first into the market (the main targets for NGN-I are:                funded by the Commission of the European Union (IST
IETF, ETSI, ITU), and it is important to be aware of                  Programme) and the Swiss Bundesamt fuer Bildung und
standards when developing products. NGN-I supports the                Wissenschaft. Without all this combined support this
harmonisation of standards contributions, in order to                 study and evaluation would not have been possible.
leverage a greater effect than if submitted independently.
The benefits of joining the NGN-I are:                                [1]
  to take an active role in shaping the NGN                          [2] subscribe
  to enjoy an environment for sharing ideas                          [3]
  to gain access to relevant documents and experts
  to learn about new NGN applications, strategies,


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