Dr. Kun Yang University of Essex, Colchester, UK

Transcription

1 Lecture #1 Network & Service Convergence - Fundamentals Dr. Kun Yang University of Essex, Colchester, UK Thursday 14th October NII, Tokyo 1 Agenda Network Convergence Wireless + wireless Wired + wireless (fixed + mobile) Service Convergence Converged Services for Mobile Devices Converged Services for core networks Q&A 2 1

2 There are many different types of wireless access networks. There will be no perfect wireless system in terms various factors such as mobility, capacity, coverage, and cost. Instead, these networks, each with its unique features, will coexist. DVB-T Satellite DVB-H RF-tag 3G Cellular (UMTS, CDMA2000, TD-SCDMA) 2.5G (GPRS) 2.75G (EDGE) Driving Forces IEEE802.11a/b/g/n (Wireless LAN) 2G Cellular (GSM, etc) IEEE (Bluetooth) Wireless Access Networks IEEE (MIH) IEEE a (UWB) IEEE (ZigBee) IEEE (Mobile BWA) IEEE a (low-rate UWB) IEEE (Fixed Wireless MAN) IEEE802.16e (Mobile Wireless MAN) There is a historic shift from PC s to mobile devices for Internet access. Technologies that enable users to seamlessly and easily use these networks are needed. 3 A Heterogeneous Wireless Network: UMTS+WiFi Current cellular systems are limited in flexibilities in that cellular architectures are fixed and bandwidth allocation cannot dynamically adapt to instant network change. As a result, some cells could be congested because of temporary events, such as traffic accidents and sports events. Proposal: introduce MANET over cellular networks to divert traffic. Existing work: icar: diversion station has only cellular interface UCAN: high-date rate, within a cell 4 2

3 Physical Characteristics of the HWN system MH2 Traffic Diversion Station #1 Mobile Host #1 Base Station #1 MH3 TDS2 MH4 MH5 BS2 TDS3 Cellular Interface Ad Hoc Interface BS: no change from the current UMTS BS TDS: with both cellular and ad hoc interfaces, deployed close to the borders of a cell MH: with only A-interface, C-interface, or both interfaces. 5 Adaptive Routing Start End MHs initiates a request but blocked Transmit data from MHs using route r Not needed in normal routing YES Is there a TDS next to MHs? NO Source Selection Procedure: find a MHj in the same cell as MHs Is MHj empty? NO YES failure YES MHj releases channel; MH uses the channel; NO Is MH empty? Route Selection Procedure: r=r k NO Source Selection Destination Selection Route discovery & selection MH =MHs; MHs=MHj; YES Is R empty? Destination Selection Procedure Route Discovery Procedure: discover route R={r k k=1,.., R } 6 3

4 QoS: QoS Mapping Heterogeneous Wireless Network BS Home WLAN TDS Egress Router IP Internet (RSVP/DiffServ/ MPLS) adsl Router AP C-to-A mapping A-to-C mapping HWN QoS Routing Internet QoS Routing Home Server (video) C-interface A-interface Wired interface End-to-end QoS K. Yang, et. al. QoS-Aware Routing in Emerging Heterogeneous Wireless Networks, IEEE Communications Magazine, Feb Page(s): Further Integration with DVB DVB-H: Digital Video Broadcast-Handheld Three types of nets Unicast+broadcast Uplink for DVB via cellular net. MH9 MH2 DVB Base Station MH5 Focus is on the network architecture and its service-driven adaptation and mngt. Cellular Cell MH1 MH4 DVB Cell Base Station #1 MH6 BS2 MH8 MH3 MH7 Cellular Interface DVB-H Downlik Ad Hoc Interface It utilizes a policy-based mngt (PBM) approach in combination with fuzzy control theory, aiming to maximize the overall effectiveness, flexibility, and robustness of the network. 8 4

5 Overall architecture UWD Service Gateway WLAN overlays UMTS. UMTS and DVB-H networks operate separately but connected via a pair of signalling gateways. UWD Service Gateway monitors the UWD network status and conducts network selection and configuration to satisfy user-perceived services. K. Yang, et al. A Flexible QoS-aware Service Gateway for Heterogeneous Wireless Networks, IEEE Networks, March Page(s): Operations How the three types of networks collaborate to fulfill a service as coordinated by the USG. 10 5

6 Agenda Network Convergence Wireless + wireless Wired + wireless (fixed + mobile) Service Convergence UEssex Research Test-bed Q&A K. Yang, et al. The Convergence of Ethernet PON and IEEE Broadband Access Networks and its QoS-aware Dynamic Bandwidth Allocation Scheme, IEEE JSAC, Volume 27, Number 2, February 2009: Background IEEE provides wireless broadband access with high bandwidth capacity, large network coverage, strong QoS support. But how to backhaul its traffic? -> EPON (Ethernet Passive Optical Network), a point-to-multipoint optical access network technology. The most popular EPON topology is tree-based architecture where transmission occurs between an optical line terminal (OLT) and multiple optical network units (ONUs). The OLT is usually connected to the core networks whereas each ONU locates at either curb (thus the so called fiber-to-the curb or FTTC), within a residential building (i.e., fiber-to-the-building or FTTB), or even to the home (i.e., fiber-to-thehome or FTTH). Of course, an ONU can be connected to an IEEE base station (BS). 12 6

7 Illustration of an EPON Network Backhauling IEEE Access Networks OLT ONU BS SS ONU BS Core SS VOD Client OLT 1:n splitter ONU BS SS VOD Server SS ONU Residential Building We assume that an EPON ONU is integrated with an BS into a converged box called Virtual ONU-BS (VOB). Partially funded by TSB/EPSRC Project: HIPnet 13 Why this Convergence? Firstly, most BSs are equipped with Ethernet interface as such can be easily connected to EPON. Secondly, both technologies share many similarities in terms of bandwidth request/allocation and QoS supporting mechanisms. Thirdly, EPON and also complement each other in that the convergence of two has the potential to combine the bandwidth advantage of optical networks with the mobility feature of wireless communications. Furthermore, this integration enables the design of joint bandwidth allocation/reservation, connection admission control and transmission scheduling schemes. These collaborative schemes are more likely to provide a close-to-optimal solution to system s overall resource management, including both wired optical resources and wireless radio resources. In return, a better support of end-to-end QoS guarantee and improvement of overall system performances such as throughput and delay can be expected. But how to design such schemes is still an open and challenging issue! We endeavor to make a first-step attempt towards this challenge by focusing on 14 bandwidth allocation. 7

8 A bit of state-of-the-art on FMC Application Layer: IMS (IP Multimedia Sub-system)/SIP (Session Initiation Protocol) -> loads of work Physical Layer: Radio over Fibre (RoF) -> tons of work MAC Layer C. Qiao. et al. appears to consider FMC in a layer other than physical layer or application layer. However, this seminal work does not reflect too much the flavor of networks. IEEE OFC March 2006 seminal work Shen et al. recently summarize the architecture issues arising in the integration of EPON and but not concrete algorithm details presented. Ref. IEEE ComMag, Aug work at roughly the same timeline as ours. Our work endeavors to design a QoS-aware dynamic bandwidth allocation (DBA) scheme at the MAC layer for a converged network of EPON and Technical Focus Firstly, to propose converged network architecture of EPON and (especially the concept of VOB) and identify the unique research issues as a result of this convergence. Secondly, to investigate a DBA scheme that is specifically designed for the WEN networks. This DBA scheme takes into consideration the specific features of the converged network to enable: (1) a smooth data transmission across optical and wireless networks, (2) an end-to-end differentiated service to user traffics of diverse CoS (Class of Service) requirements. Here the end-to-end means from a connection originated from an SS to the OLT. This QoS-aware DBA scheme shall ensure certain fairness under network traffic saturation condition along both station dimension and CoS dimension. CoS fairness specifically means that the low-priority traffic (such as best effort traffic) shall not be significantly disadvantaged under network saturation condition. The proposed DBA scheme, called WE-DBA for WiMAX-EPON DBA 16 8

9 Virtual ONU-BS (VOB) Box logical architecture hardware layout 17 Bandwidth Request & Grant The VOB queues are presented as virtual queues by dashed lines because these queues represent the bandwidth requested instead of the real data. EPON: Multi-Point Control Protocol (MPCP); IEEE has similar mechanism and procedure. These standardised mechanisms have defined the precise format for bandwidth request and grant messages as well as their processing. However, no DBA algorithm is specified. Note that VOBs employ MPCP for bandwidth request and the mechanism 18 for bandwidth grant. 9

10 Illustration of Bandwidth Request and Allocation Grant per CoS Refer to the IEEE JSAC paper for technical details and discussion. 19 DBA at OLT B avg VOB ( T = EPON cycle n T ) R 8 n g n: # of VOBs; Tg: guard time R Mbps: EPON trans. rate B 3 req req i = B i, j j = 1 i: VOB; j: CoS n = i= 1 excess avg req avg B ( B B ) ( B > B VOB g avg B = min( B + B i VOB i excess i, B VOB req i ) req i ) t g = ( B 8) R Written in the MPCP GRANT message len i i / 20 10

11 DBA at VOB B = α min avg BE B BE avg B BE, r+ 1 = TrafficBE, r B + avg avg BE, r + 1 = ( BBE, r 1 TrafficBE, r ) / 2 21 Benchmarks: Evaluation Design DBA1: both the OLT and VOBs statically allocate bandwidth (equal share) to its client stations. DBA2: EPON static whereas dynamic (the other way round is less common) Test design: To evaluate against benchmark to show the benefit of dynamic in terms of throughput and delay To evaluate itself under different conditions. In terms of throughput and delay under different serving cycles, types of services, channel utilization, and BE windows 22 11

12 Overall Throughput of WEN under different DBA schemes 23 Average Delayof WEN under different DBA schemes 24 12

13 Thoughput under different Serving Cycles 25 Delay under different Serving Cycles 26 13

14 Average Delay for Types of Services 27 Channel Utilization 28 14

15 Effect of minimum bw allocated to BE 29 Conclusions PON at MAC appears to be beneficial though just some very limited preliminary work being carried out. However, this is a massive research topic and much more effort is needed. Other topics such as scheduling and admission control, a comparative study on the performance differences between a centralized control mechanism (carried out by the OLT) and a cascading decision making strategy. Investigation into the effect of mobility on network performance. Long-term work includes research into a fully unified hardware VOB

16 Agenda Network Convergence Wireless + wireless Wired + wireless (fixed + mobile) Service Convergence Converged Services for Mobile Devices Converged Services for core networks Research Test-bed Summary, Q&A 31 Pervasive Service Engineering Policies Service Creation Module generates Pervasive Service EPSRC Project: PANDA BT Project: MOSE Static Service Creation Dynamic Service Execution/Adaptation Sensor Network Sink Pervasive Service Information Model Fixed IP Node Registers context Context Monitoring Module Java Virtual Machine Network APIs Active IP Router Passive IP Router events PS Adaptation Module Ad hoc Service Discovery Module 3G/4G handset WiFi mobile Node Basic methodology: - saturated to every stage of the PSE lifecycle A range of research issues concerning the whole lifecycle of pervasive service engineering: Service Description, Service Creation, Service Deployment, Service Discovery, Service Composition, Service Adaptation. Policy-based: more flexibility, and matching with the network management method Model-driven (OMG MDA-Model-driven Architecture): platform-, language- and middleware-neutral features, and open source from Eclips. Context-awareness 32 16

17 A GUI for Pervasive Service Creation PS Execution Environment Android Version PC/PDA Version 34 17

18 Demo (source code free downloading) 35 Service Convergence at Core Networks EU FP7 ICT Project GEYSER (Generalised Architecture for Dynamic Infrastructure Services), 4 th call, starting on 1 st Jan to support 'Optical Network + Any-IT' resource provisioning; green issues With Prof. Dimitra Simeonidou (dsimeo@essex.ac.uk) 36 18

19 Contact,Q&A Dr Kun Yang, Reader School of Computer Science & Elec. Eng. (CSEE), University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK