1. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Multimedia Services using IP over Bearer Networks: Quality of Service Aspects based on ACTS Guidelines SII G05 and SII G10 presented by Cees J.M. Lanting Datsa Belgium sprl, Belgium ACTS projects EURORIM and PRIME

2. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Overview Assuming a 3 layer model –applications and information services –an overlay IP based application networks –underlying telecom bearer network(s) Different origins IP and Telecom networks Expressing QoS requirements Meeting known QoS requirements in an IP based overlay network Conclusions

3. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Different origins Telecom networks have been developed to support and meet the requirements of sets of services: –each service has precisely defined requirements for the underlying services internet originates from the datacommunications and dataprocessing environment: –applications designed to work with what is available –application requirements flexible and tolerant –best effort therefore often acceptable

4. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Precise QoS requirements often assumed precise QoS requirements are known, implicitly or explicitly however, QoS requirements may not actually be known, or be known accurately useful to make a classification of application services on the basis of their ability to accurately express QoS requirements, either implicitly or explicitly the ability to express QoS requirements is not the same for different communication modes

5. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Expressing QoS requirements Type IConnection-Less (CL) mode services, characterised by undefined flow related QoS requirements Type IIConnection (CO) mode services with weakly defined flow related QoS requirements: ‘weak flow CO mode’ Type IIIConnection (CO) mode services with well defined flow related QoS requirements: ‘strong flow CO mode’

6. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Expressing QoS requirements Type ICL mode; for example, –e-mail –DNS Type IIweak flow CO mode; for example, –file transfer Type IIIstrong flow CO mode; for example, –videoconferencing –speech

7. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Example: web access The nature of web access incurs unknown QoS requirements: low to medium requirements for navigation QoS requirements imposed on the fly by application server - terminal, such as: –medium to high bandwidth, non real-time (e.g. ftp) –low to medium bandwidth real-time (voice, audio) –high bandwidth real-time (video)

8. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Example (telecom): fixed-mobile call Also in telecom QoS may not always be known accurately for example, when a call is made originating from a fixed network, with as destination, directly or after deflection, a mobile network subscriber: fixed network versus mobile network QoS requirements

9. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Meeting known QoS requirements in an IP based overlay network current generation IP suite differs significantly in its nature from typical telecommunications protocols and services; it does not provide for a defined flow related QoS Extension protocols have been defined or proposed to add support for different QoS classes, and different QoS strategies have been proposed The next generation IP also provides mechanisms for management and control of network resources

10. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Meeting QoS requirements in current generation IP based overlay network basic IPv4 suite of protocols does not provide for the –management and –control of network resources necessary to achieve a defined flow related QoS different QoS strategies have been proposed, for example –controlled load, –guaranteed service

11. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Meeting QoS requirements in next generation IP based overlay network Extension protocols have been defined or proposed to add support for different QoS; mechanisms proposed include resource reservation (RSVP) Next generation IP suite, IPv6, also provides mechanisms for management and control of network resources, through labelling and priority indication of flows; these mechanisms can be used also in combination with extension protocols

12. AIMS’99 Workshop Heidelberg, 11-12 May 1999 A comparison, from a network capabilities point of view

13. AIMS’99 Workshop Heidelberg, 11-12 May 1999 A comparison, from a network capabilities point of view (cont.)

14. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Conclusions applications and multimedia services cover a wide range of QoS requirements; they also differ in their abilities to communicate their QoS requirements switched telecom networks are capable of providing a guaranteed, or a near-guaranteed flow related QoS an IP application network overlaying telecom networks used as bearer networks, the IP network hides the underlying network(s) from the application; bearer networks can only indirectly contribute to the QoS provisioning in the IP application network

15. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Conclusions (cont.) In an IPv4 only based application network, the QoS management will be limited, restricted to strategies as best effort, controlled load and guaranteed service In an extended or IPv6 based application network, additional facilities are available to QoS management; the application network may use facilities in the bearer networks other than in an averaged way difficult to provide in an open environment the same levels of QoS possible in telecom networks

16. AIMS’99 Workshop Heidelberg, 11-12 May 1999 Relation with network organisation Horizontal network organisation has an impact on the possible co-ordination or ‘transferability’ of control across network domains: for example, ‘priority’ Also more generally, networks may have limitations with respect to the horizontal organisation: for example, lack of ‘visibility’

17. AIMS’99 Workshop Heidelberg, 11-12 May 1999 High QoS versus other approaches As an alternative to providing a guaranteed high level of QoS, other ways may be explored: provide users required QoS in relation with charging; a possible mechanism would be based on a link between the QoS and charging