1. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Basic Functionality of Quality of Service in Multimedia Networks Piet Van Mieghem

2. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Outline tIntroduction n Multimedia n QoS market trends n Packet networks & statistical multiplexing tQoS : What? n Basic Network functionality required tConclusions

3. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Outline Introduction QoS : What? Conclusions

4. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Evolution Advances in Micro-electronics Fast computers Multimedia Data World non-real time Telecom World real-time best of both worlds High speed networks

5. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Multimedia Marketing Trends tEven if a minority asks for QoS, the network provider is forced to invest in QoS to maintain (or enlarge) its market share tQoS provisioning linked to pricing will be a competitive weapon in future telecommunications networks MULTIMEDIA Discovery of Internet (Connectivity) Attraction to Internet (Simplicity) Used to Internet Frustration with low QoS inherent in best effort Willing to pay for QoS guarantees ubiquitous guaranteed quality low cost Business on Internet TODAY

6. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Customer Centric Evolution QoS Complexity QoS granularity BE prioritised BE impact of guaranteed QoS CoS Customer fine-tuned QoS Time flat fee detailed invoice end system network centric CL CO

7. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Stochastic Nature of Information Prob[x< S< x+dx] S(t) t x correlation depth k k R(k) = E[S(t+k)S(t)] E[S] max(S) burst size PCR SCR MBS

8. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Statistical Multiplexing 4 3 2 1 0 120100806040200 time (ms) 4 3 2 1 0 120100806040200 time (ms) bandwidth (Mb/s) No statistical multiplexing  PCR = 4 Mb/s Statistical multiplexing min. capacity: 3.4 Mb/s

9. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Outline Introduction QoS : What? Conclusions

10. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem QOS: definition tApplication layer: Grade of Service (GOS)  hard to define precisely (perceived quality, human appraisal)  alternative definition: GoS is related to blocking/failures tTransport layer: QoS routing (end-to-end)  path through network subject to QoS requirements tNetwork layer : Quality of Service (QoS)  a measure (a ratio, a maximum, an average/variance/ quantile of a probability distribution,...) acting on a property (a loss, a delay, a cost,...) of a cell/packet flow

11. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem QoS Associations tQoS is related to RESOURCES in the network n states in the network, basically CO in practice n end systems cannot control network resources driver to a network centric view current Internet opportunity for network operators and network manufacturers tControl of QoS (i.e. control of resources) is key n resources = assets = money/capital n QoS control implies OPTIMALITY, because suboptimal control simply means loss of revenue importance of Admission Control

12. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Basic Network Functionality for QoS provisioning Functionality real-time notion multiparameter routing signalling traffic management admission control input control failure control queue control priority control ATMIP AAL1 PNNI PNNI/BISUP ATC’s vendor specific GCRA vendor specific intelligent scheduling POB,PBS,HOL,EPD,.. RTP QoSR (still empty) RSVP (partly) Integrated Services (current efforts)

13. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem QoS Routing tQoS Routing = Multiple parameter routing subject to constraints n Link metrics are vectors n NP-complete good heuristics needed tPolicy Routing is related to QoS routing tRouting with partial information A B C DEF G H IJ K delay: 10 ms bandwidth :100 Mb/s cell loss ratio: 1.0e-6 administrative weight: 4

14. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Signalling ATM Network setup call proceeding call proceeding connect connect ack setup time tFunctionality that transports control information for installing resources along the path of each individual flow (or connection) n consequence of CO-mode * Complex protocols * Limited number of connections

15. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Traffic Management tFinal (nodal) decision on installing resources: n admission function (CAC) n CAC is inherently difficult tNeed for input control n never trust the user n check the contracted traffic parameters tCongestion functionality tVarious ATM bearer capabilities (DBR, SBR, UBR, ABR, GFR,...) or Internet services (guaranteed service, controlled load, BE)

16. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem Outline Introduction QoS : What? Conclusions

17. AIMS Workshop Heidelberg, 9-11 March 1998 Piet Van Mieghem QoS : Summary tMultimedia will evolve to QoS-awareness and eventually to QoS guarantees tNo smooth evolution from BE to guaranteed QoS provisioning QoS complexity sky-rockets due to guarantees tQoS is complex and requires additional network functionality tQoS is linked to revenue (money) via network resources QoS is associated with optimality tOptimal QoS Control needs stochastic analysis Still a long way to go