CONCLUSIONES Y RECOMENDACIONES
BIBLIOGRAFÍA BÁSICA Primer capítulo:
Advanced communications would rely on individual advanced technology consumer products, a communal infrastructure as well as an abundance of diverse of content.
As stated in the previous section telecommunications might in the future be likely to exhibit a more distinct separation between NOs and SPs, i.e. between infrastructure or resource and content or services. In addition, as the range of available services diversifies, customers’ requirements of a given service widen and the elasticity o f tolerance decreases, the marketplace is likely to segment and SPs will be ‘forced’ to target the individual customer profiles more exactly. Within telecoms there seems to be evidence to suggest that this is most likely to be achieved in terms o f more selective ‘tailoring’ o f service
packages to the individual needs and requirements of the various customer groups and possibly the individual customers. Comparatively NOs are likely to seek to reduce their cost-margins by consolidating the infrastructure and systems necessary to provide service.
Companies are already beginning to ‘un-bundle’ the services they provide in an effort to make the individual components they offer capable o f being more specific to the individual customer’s needs. It is, for example, not uncommon for major operators to run parallel customer support department for residential and business customers. The author believes that this trend is likely to continue and evolve from support to services and possibly eventually within single services.
From the perspective o f the telecommunications engineer, such an evolution is likely to be perceived as a requirement for an increasing diversification in types of traffic for which transport is supported. At a later stage, this may be further supplemented with a need for quite varying QoS matrices, such as delay and loss tolerance and priority, for one and the same service.
Fig. 1.2 below plots some examples o f both services and general communication infrastructures bit-rates versus typical session durations. It can be seen that the (commercially) available communication infi’astructures which are capable o f the performance necessary, at least in terms o f bit-rate, typically are limited to Local Area Networks (LANs). In other words, although the terminations and terminal equipment potentially are suitable for a future advanced communication infi’astructure they are today
See also section 5.1 “General statement of the local access requirement” in chapter 5 (part II) for further discussion regarding some of the issues introduced in this section (with particular reference to the access network).
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only applied in smaller ‘closed’ systems with short calP holding-times. Although a large proportion of the reasoning is undoubtedly associated with economic arguments connected to the implementation it also implies that future communication networks and protocols are likely to exhibit higher communication speeds and more complex termination equipment closer to the customers
10’°7 10^ bits 10^^ bits High performance inter processor communication rates HDTV A4 page at 300dpi Video A4 page by email Audio Voice 10^ bits 10° bit 10 bits Durations (sec)
Fig. 1.2 - Examples of traffic bitrate versus duration
In addition to the plethora of communication speeds intimated in Fig. 1.2 above, the different services delivered are likely to have varying QoS metrics as well as typical source traffic characteristics. Fig. 1.3 below plots some examples of Burstiness, defined as the ratio o f mean to peak, information rate for services and communication rate (capability) for general communication infrastructures (similar to Fig. 1.2). It can be seen that, as in Fig. 1.2, the information rate characteristics of future services is likely to be closer to communication rate profiles used in computer and |u-processor systems than current telecommunication infrastructures. This would seem to be yet another indicator that the boundaries between telecommunications and computing are blurring. It would also seem to
^ call in this instance denotes the entire session of or data transfer associated with the service provided as perceived at the application layer, i.e. OSI layer 7
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to point to a requirement for future communication protocol suites needing increased diversity of session and QoS metrics One only has to look to the ongoing evolution of e g the ATM and to a lesser extent the IP protocols to realise that this requirement already has been recognised by the IT-fraternity.
As the number of services offered by telecommunication SPs increases and more features, such as e.g. (complex) IN (Intelligent Networking) services, are 'built-in ’ to the network, it will become increasingly complex to disentangle service and infrastructure, if the current approach to network design is not changed. Certainly ‘transparency’ of the transport layer will be an absolute requirement and possibly even (partial) transparency of the physical, in the form of e.g. ‘optical transparency’ would become desirable. Perhaps not surprisingly the larger more established (ex-monopoly) operators are amongst the more staunch critics o f ‘un-bundling’ and whether it should be imposed by law or legislation. However, it is the authors’ belief that if even huge (multi-national) operators do not open themselves to ‘targeted marketing’ and the network, system & technological requirements that come along with that, they may face a real danger of becoming huge immobile and ‘dead’ dinosaurs.
2 3 00 1 00
10
-2_ .10
-310
'Low
Speed Data Voice I Audio Terminal to hostLow
SpeedLAN
uncompressedHDTV
Video compressed J Coimectia»leæHigh
Speed LAN Super Computer i c 10= 1 0 ' 1 0 ' 1 0 ' 1 0 '10
10Bit/s
Fig. 1.3 - Examples of traffic burstiness versus bitrate
It is clear from the above discussions that one overwhelming issue o f tomorrow’s IT service provision will be bandwidth or more specifically information capacity of the networks & systems.
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However, another debate, which has recently started emerging, is mobility. The advent o f mobile communication systems in the form of e.g. cellular and GSM telephones is perhaps arguably the most striking change in telecommunication services in this decade. Although many working in telecommunications assume that mobility posses little or no threat to the existing fixed networks this is almost certainly shortsighted. Presently wired and wireless access telephony services coexist but as Simon Forge o f Cambridge Strategic Management Consultants, author o f the study: “Near-zero tariff telecommunications”, argues “mobile telephones may in time do to public networks what the railways did to canals”; namely, effectively replace it.
There already is quantitative evidence emerging that there within some user-groups is a shift o f preference from fixed- to mobile-line based services: “Worldwide, one new
telephone subscriber in six gets a mobile phone” and “In Sweden one person in [every] six has a mobile phone. Indeed, fixed-line connections are now declining: flighty young people choose to have a mobile phone when they leave home, rather than pay a new fixed-line connection every time they move.” [13].
What is missing in the mobile-telecoms market at the moment would seem to be bandwidth. Cellular telephones typically use a large proportion of the available ‘communication space’ to facility robust transfer of data under roaming conditions. The terminal equipment, in this case the customers’ handset, use a large proportion o f the available ‘address space’ to switch between alternative transmitters in order to increase its robustness to (transient) fading conditions of one of them.
The PHS (Personal Handiphone System) system does not employ diversity reception and thereby increases the proportion of the address space available for communication. This system will therefore be able to transmit still graphic images (and maybe even low ffame-rate video). A ‘price’ o f this approach is naturally that a customer would probably not be able to receive data while in transit in e.g. a speeding car or train; but this is also balanced by the likely much reduced ‘cost’ o f the NTE (NT (Network Termination) Equipment), i.e. the handsets, due to the lack o f advanced switching technology.
The objective o f the above comparison systems in not to measure the relative merits o f the two technologies, but simply to add weight to the argument that customers, in the future, may prefer to be able to have a single handset capable o f terminating signals from what now are separate systems, say satellite, cellular (GSM), PHS, paging and landline systems and automatically switching between them allowing a customer to be reached at any time on a single number; or possibly multiple numbers all terminating on the same piece of NTE. A precursor o f the next generation of NTE might be the Nokia 5020 GSM mobile phone which allows the operator to programme different responses to an
47 incoming call, e.g. ring (& answer), direct to VM (Voice Mail) or redirect to another number, dependent on the pre-programmed categories of CLI (Calling Line Identification) numbers.
The objective of the above examples and discussion is as a general introduction and background to a few o f the fields the author believes to be relevant to the general study of telecommunications and the context within which the work & results presented in the remainder o f this thesis was performed & derived.