| Abstract | The structure of today’s telecommunications market is getting more complex than ever due to multiple reasons. First of all, the traditional monopolistic Public Network Operators’ (PNOs) market is moving towards an open market with many various players. Such liberalisation is followed by a strengthening of regulatory directives that support and favour the open market, e.g. Open Network Provision (ONP) directives from the European Commission (EC). Other characteristics of such market include the ever increasing number of: • Users with the demands for real-time multimedia applications that have high requirements on the quality of services used to support them. • Applications and services that are included in products delivered to customers. Their diversity and the fact that these are offered on various functional levels add to the complexity of the composition/ packaging process. • Providers playing different roles and offering a variety of services to users. • Technologies implemented in networks, as well as their combinations and hybrids. The structure and topology of networks are also getting more complex both logically and physically. The market described above is called a multi-service multi-provider market implying that several services are provided by several network infrastructures administrated by different providers. In such a market, a provider needs to co-operate with its sub-providers in order to deliver end-to-end a service with the agreed quality to the user. At the same time, the sub-providers may aim at the same market segment by offering same/similar products, i.e. they are potential competitors. One of the factors users observe and consider when differentiating providers in the above described market is the Quality of Service (QoS). It is important for users to avoid the consequences of not completing their tasks because the quality of the service they agreed and used was poor. Therefore are users willing to pay more to get some guarantees on the quality. Consequently, the QoS handling becomes very important for a provider operating in this type of a market. Handling QoS includes tasks like QoS analysis, provision, and assurance. The tasks are a challenge for the provider because they consider not only the implementation and the usage of different mechanisms for QoS support, but also the complex problem of assuring the quality of the service supporting traffic that crosses several domains outside of his administration and control. Note that though always positive for users and the welfare of a society, it may not always be fruitful for the provider to absolutely play on the QoS. Offering services with QoS guarantees makes him more visible to the users in the market. This usually results in the increased number of customers and reduced churn implying an increase of the profit. But, at the same time, he is more exposed to the observation and the criticism from e.g. regulatory bodies, customers organisations, etc. Different measurements need to be performed to report that agreed QoS was delivered. Promising, but not delivering the quality as agreed would seriously harm provider’s credibility and profit. A provider offering its services in an Internet Protocol (IP)-based environment needs, in addition, to tackle the challenge of the technology immaturity and partially-developed/incomplete mechanisms for QoS support. Not forgetting existing technologies, new ideas, approaches and paradigms need to be introduced step-wise and incrementally.
Having a generic QoS framework that can be reused in any emerging situation would enable a provider playing in the multi-service multi-provider environment to respond to these challenges in an efficient, organised and cost-effective way. The generic QoS framework coheres QoS-related issues; it envelops the terminology and concepts that can be used independent of the service, technology, network architecture, business models and roles the provider is considering in the particular situation. Backward compatibility with already implemented QoS framework(s) and regulatory directives is a necessity for such a framework. Theoretical principles are of limited value if their usage in practice is not structured and verified. Hence, a methodology for applying the concepts of the framework is needed as well. Some parts of the methodology may even be automated, so that additional effectiveness is achieved. In the existing literature several approaches to the QoS framework may be found. Different standards and the results of various QoS-related projects initiated by standardisation bodies (ITU-T, ETSI, IETF, ISO/ODP), industrial fora (TMF, TINA, OMG, EURESCOM), and academic fora (universities) bring different QoS frameworks that are concerned with various aspects of the service provision and QoS support end-to-end. Few of them are composing both technical and business viewpoints and aspects in a complete picture. Even less of them are readily applicable in a multiservice multi-provider environment. These facts motivated the development of the generic QoS framework called EQoS+ framework, which is described in this thesis. It is a successor of the EURESCOM QoS (EQoS) framework and represents the continuation of the work started in the EURESCOM P806-GI project [p806-site]. As stated in [p806-d1], the EQoS framework is a generic QoS framework meaning that it is service/technology/network independent. Its usage should simplify the definition of interconnection agreements and, in particular, the specification of the QoS aspects in them. Any company can benefit from using a versatile framework repeatedly in order to avoid multiple repetitions of similar tasks (e.g. QoS specification, interface identification, measurement schemes identification, etc.). The EQoS framework addressed the challenge of QoS offer and management in a multi-provider environment by focusing on the agreement made between a user and a provider for a given service. This introduces the concept of one stop responsibility of a given actor (the primary provider) to another (the user). The multi-provisioning issues are addressed by allowing agreements to be defined recursively between any pair of actors, one in the role of a “provider”, the other in the role of a “user”. This recursive approach acknowledges that the delivery of a service depends on the successful operation of many components, particularly when working within a multiprovider environment. Though the EQoS framework offers a basic structure, several issues have been left open due to the limited resources in the project. The EQoS+ is a framework that enhances the EQoS basis. It is comprised of three elements: terminology, concepts, facilities. In the EQoS+ terminology, the EQoS basis is enlarged by introducing the definitions for several new terms; in particular those relevant for tackling business aspects of QoS. In addition to the one stop responsibility concept, three new concepts are introduced in the EQoS+ to further help establishing a common view between the provider and the user, and to enable a further decomposition of complex service provisioning/ delivery scenarios in relation to the functional layers and time: 1. Agreed QoS concept for establishing a common reference to QoS between a provider and a user; 2. Timelines and granularity concept, which structures different types of the agreements and explains the granularity and choice of the QoS parameters in their contents. The agreements are also related to different stages and instances of services as offered to users; 3. Layering and mapping concept that considers QoS mapping issues both within layered network models and in a value chain; it also relates the QoS requirements to the resource reservation.
The EQoS+ facility SLA template proposes a generic structure for both an agreement in general, and its QoS-related part in particular. The informational model of the template may be implemented in a protocol enabling thus automatic negotiation/trading between two devices. Consequently, the negotiation process would be more automatic and effective. A methodology for applying the EQoS+ framework is presented in the thesis as well. It is described semiformally by using a practical object-oriented approach and the Unified Modelling Language (UML) [uml-spec] for the visualisation, rather than classical mathematical rigor. The methodology defines the information needed as input for applying the EQoS+ framework when considering QoS for a product/service; the procedure itself is described briefly leaving to the provider applying the framework an opportunity and privilege to implement his own solutions; the output is comprised of known relationships with selected sub-providers, and agreements made both with them and users. Also, the phases of a generic Service Life Cycle (SLC) are discussed and related to different QoS activities and EQoS+ elements. Finally, any new theory and methodology should be verified, and here the verification is done by analysing the applicability of the EQoS+ framework on an IP telephony service provision case. The benefit of the EQoS+ approach is that it formally accepts that the delivery of a service is depending on the successful operation of many components, and that the operation should be traceable and measurable, particularly when working within a multi-service multi-provider environment. It is also a step forward that QoS is related to the agreement rather than to the satisfaction of the user. The EQoS+ framework is a basis for tackling the QoS issues in any situation, and it has been already used in several IP- and UMTS-related projects [p906-d3], [p1103-d1], [p1103-d4], [rohn2], [jens5]. It is also important to note that while introducing new concepts, the EQoS+ framework also smoothly incorporates the key features of existing QoS frameworks. Though it offers several principles for treating QoS from a holistic perspective, a number of issues is still open for further study: • Business decisions in the process of negotiation, • Business games and optimisation related to the QoS parameters decisions, • The communication of the QoS parameters to the human end-users, e.g. by developing indexes, • More detailed consideration of the SLC phases and its relation to the organisational theory, • Consequence and risk analysis related to the QoS. Each of these elements represents a piece of the puzzle that would result in a QoS handbook applicable in multi-provider environments [espv2]. |
| Abstract (english) | Struktura današnjeg telekomunikacijskog tržišta postaje sve složenijom. Razlog tome je u prvom redu liberalizacija tržišta gdje je tradicionalni monopolizam javnih (državnih) davatelja telekomunikacijskih usluga zamijenjen otvorenim tržištem s više davatelja usluga. Liberalizacija je propraćena strožijim regulacijskim propisima koje podržavaju principe slobodnog tržišta, npr. ONP upute koje je izdala Europska zajednica. Ovakvo tržište dodatno podrazumijeva i stalni porast broja: • korisnika koji zahtijevaju multimedijske usluge koje su pružene u stvarnom vremenu, • aplikacija i usluga koje imaju strožije zahtjeve na kvalitetu usluge, • davatelja usluga koji nude te usluge korisnicima i pri tome igraju različite poslovne uloge, • tehnologija (kao i njihovih logičkih i fizičkih kombinacija) implementiranih u mreži za podršku tih usluga. Takvo tržište se naziva tržište s više davatelja usluga i ukratko se može opisati kao tržište u kojem je veliki broj usluga pružen korisnicima preko raznovrsnih mreža kojima upravljaju ražličiti davatelji usluga. Davatelj usluga koji operira na ovakvom tržištu mora surađivati s drugim davateljima da bi zadovoljio korisnikove zahtjeve na kvalitetu usluge s kraja na kraj. Istovremeno se taj davatelj usluga morati natjecati s drugim davateljima oko korisnika.
Jedan od bitnih faktora koji korisnici razmatraju prilikom odabira davatelja usluge na otvorenom tržištu jeste kvaliteta usluge (Quality of Service, QoS). Razlog zašto je kvaliteta usluge značajna korisnicima je činjenica da su posljedice degradacije kvalitete na (ne)ostvarenje nauma i cilja korištenja same usluge prevelike za korisnika, tako da je on voljan platiti više za osiguranje kvalitete s kojom može računati na ostvarenje svojih ciljeva. Zato se davatelji usluga trude privući korisnike osiguranjem kvalitete usluge. No, analiza i osiguranje kvalitete usluge na tržištu s više davatelja usluga je izazov za svakog davatelja usluga. Naime, sama ugradnja različitih mehanizama za podršku kvalitete usluge unutar jedne domene je složena, a ako uz to davatelj usluga pruža usluge na tržištu s više davatelja usluga onda on mora dodatno riješiti problem podrške i osiguranja kvalitete usluga za promet koji prolazi kroz domene koje su izvan njegove administrativne kontrole. Bolja kvaliteta usluge je gotovo uvijek pozitivna za krajnjeg korisnika i društvo u cjelini, ali ne nužno i za davatelja usluga koji nudi usluge s garantiranom kvalitetom jer je on tada više izložen tržištu. S jedne strane, veći broj korisnika se odlučuje koristiti usluge tog davatelja, njihova odanost je jača, a to implicitno znači i veću zaradu. No, s druge strane je davatelj više izložen budnosti regulacijskog tijela, korisničkih organizacija, itd. Različita mjerenja se moraju provesti kako bi se potvrdila isporuka kvalitete usluge sukladno sporazumu. Kršenje sporazuma o kvaliteti usluge može ugroziti ugled davatelja usluge, a posljedično smanjiti broj korisnika i zaradu. Oni davatelji usluga koji pružaju IP usluge su suočeni s još većim izazovima, budući da tehnologija sama po sebi nije još potpuno razvijena. Ne zaboravljajući postojeće tehnologije, nove ideje i pristup rješenju problema QoS se moraju postupno uvesti. Kako bi se mogao lako prilagoditi novim uvjetima na dinamičnom tržištu s više davatelja usluga, davatelj usluga mora imati alat koji mu omogućava da uskladi način razmišljanja i pristupa problemu kako unutar tvrtke tako i u mješovitim projektima između više tvrtki. Za problem kvalitete usluge, takav alat je radni okvir za analizu kvalitete usluga (tzv. QoS radni okvir) koji uključuje terminologiju, koncepte i pomagala. QoS radni okvir u okruženju s više davatelja usluga omogućava jednoznačno razumijevanje bitnih pojmova između partnera koji se bave problemom analize i pružanja kvalitete usluge, kao i dekomponiranje složenog problema na sastavne dijelove koji se onda mogu razumjeti i jednostavnije riješiti. Ako je radni okvir uz to još i generički, tj. primjenjiv na bilo koju situaciju gdje je npr. uvedena nova usluga, poslovni model i/ili tehnologija su se promijenili, itd., onda je davatelj koji ga koristi pripremljen da reagira efikasno i brzo na česte promjene na dinamičnom tržištu. Generički QoS radni okvir bi uz to trebao biti otvoren za uključivanje različitih regulacijskih propisa i morao bi uvažiti rezultate radnih okvira koje davatelj usluga već koristi i postupno ih zamijeniti. Teorijske postavke i koncepti imaju ograničenu vrijednost ako nije jasno kako ih koristiti u praksi. Zato je potrebno razviti i metodologiju koja pokazuje kako se koncepti mogu primijeniti na konkretnom slučaju u svakodnevnoj praksi. Danas se koriste različiti QoS radni okviri, razvijeni unutar jedne tvrtke ili pak standardizirani u ITU-T, ETSI, ISO. Osnovni nedostaci postojećih radnih okvira su činjenica da oni nisu u prvom redu razvijeni za tržište s više davatelja usluga, kao i činjenica da se poslovne i tehničke strane vezane uz pružanje kvalitet usluge promatraju odvojeno, a ne kao cjelina. To je motiviralo razvoj generičkog QoS radnog okvira EURESCOM QoS (EQoS) u EURESCOM projektu P806 [p806- site]. Kako je to rečeno u [p806-d1], EQoS radni okvir je primjenjiv na različite situacije koje uključuju bilo koju uslugu, bilo koju tehnologiju, bilo koju (poslovnu ili tehničku) konfiguraciju. Primjena EQoS-a u praksi omogućava davatelju usluga da, npr. jednostavnije dizajnira ugovore o razini usluge, a posebno dio ugovora koji se odnosi na kvalitetu usluge. EQoS radni okvir rješava izazove pružanja i osiguranja kvalitete usluge na tržištu s više davatelja usluga rekurzivnom primjenom tzv. koncepta jednostruke točke odgovornosti (one stop responsibility). Pojednostavljeno rečeno taj koncept kaže da glavni davatelj usluga ima jedinstvenu odgovornost za kvalitetu usluge pruženu njegovom korisniku bez obzira na složenost lanca isporuke usluge. EQoS tako rješava dio problema dekomponiranjem tržišta na elementarne parove korisnik-davatelj usluge, ali ostavlja jedan broj pitanja otvorenima. Neka od tih pitanja su razmotrena u ovoj disertaciji i ponuđeno je rješenje u obliku EQoS+ radnog okvira koji poboljšava EQoS. EQoS+ se sastoji od tri elementa – terminologije, koncepata i pomagala. Nova terminologija uključuje definicije nekoliko novih pojmova, a posebno onih vezanih uz poslovne aspekte kvalitete usluge. Osim koncepta jednostruke točke odgovornosti, EQoS+ uvodi tri nova koncepta koji omogućavaju opis i rješavanje problema vezanih uz pružanje kvalitete usluge na tržištu s više davatelja usluga: • dogovorena QoS (agreed QoS) koncept koji uspostavlja zajedničku referencu za kvalitetu usluge između korisnika i davatelja usluge; • vrijeme i granularitet (timelines and granularity) koji struktuira različite ugovore ovisno o odnosu korisnika i davatelja usluge u određenom trenutku, kao i izbor relevantih QoS parametara koji se uključuju u te ugovore; • slojevitost i preslikavanje (layering and mapping) koncept koji analizira preslikavanje QoS parametara kako između različitih mrežnih slojeva tako i unutar lanca isporuke usluge; ovaj koncept povezuje kvalitetu usluge i resurse neophodne da se ta usluga pruži. Konačno, novo pomagalo (SLA template) predlaže uzorak generičke strukture sporazuma o razini usluge koji se može npr. ugraditi u protokol i na taj način se sklapanje i pregovaranje određenih tipova ugovora može automatizirati i ubrzati. Osim teorijskih principa i metodologija za primjenu EQoS+ je predložena u disertaciji. Metodologija je formalizirana primjenom objektno-orijentiranog pristupa i Unified Modelling Language (UML)-a, i opisuje ulazne informacije neophodne da bi se EQoS+ mogao uspješno primijeniti; principe procedure koju davatelj usluga koji primjenjuje EQoS+ mora izvesti ; izlazne rezultate koji uključuju odluku o partnerskim davateljima usluga uz čiju će pomoć glavni davatelj usluga osigurati uslugu s dogovorenom kvalitetom svom korisniku i sadržaj ugovora sklopljen kako s partnerima tako i s korisnikom. EQoS+ pristup podrazumijeva da pružanje usluge kao cjeline ovisi o uspješnoj suradnji više komponenata, čije djelovanje mora biti moguće pratiti i mjeriti, posebno u sredini s više davatelja usluga. Korak naprijed je i način razmišljanja gdje se kvaliteta usluge ne vezuje uz korisnikovo zadovoljstvo već uz sporazum. EQoS+ je do sada primijenjen u praksi za npr. IP- i UMTSslučajeve ([p906-d3], [p1103-d1], [p1103-d4], [rohn2], [jens5]). Isto tako je bitno naglasiti EQoS+, iako uvodi nove koncepte EQoS+, usvaja osnovna odličja postojećih QoS radnih okvira. Iako EQoS+ nudi nekoliko principa koji pospješuju analizu i osiguranje kvalitete usluge, to je veliki dio pitanja otvoren za daljnje istraživanje, npr.: • poslovne odluke u procesu pregovaranja, • poslovne igre i optimizacijski problemi vezani uz odluke oko QoS parametara, • kako načiniti QoS parametre što razumljivije korisnicima, npr. uvođenjem indeksa, • detaljnije istraživanje životnog ciklusa usluge i njegova odnosa s organizacijskom teorijom, • posljedice i analiza rizika vezani uz QoS. Svako od ovih pitanja predstavlja jedan dio slagalice koji bi rezultirao u QoS priručniku primjenjivom na tržištu s više davatelja korisnika. |
