Presentation on theme: "Policy-based QoS Framework for Multi-service IP Networks Hoon Lee Network and Service Assurance Lab. Dept."— Presentation transcript:
Policy-based QoS Framework for Multi-service IP Networks Hoon Lee E-mail: email@example.com@changwon.ac.kr Network and Service Assurance Lab. Dept. of Information & Communications Engineering Changwon National University Changwon, Korea
Service Trends: Triple Play=Voice+Data+Video There exists no killer applications! Pack them up!! Voice from Phone Data from PC VoD/ TV Videophone Triple Play Services: - Italy: FastWeb - Japan: NTT RENA, KDDI, SoftBank - Korea 1. KT: All up prime (Megapass+VoIP+Videophone+Messaging+Broadcasting) 2. Dacom: Internet+VoIP+ Broadcasting 3. Hanaro Telecom: 2 Scenarios PSTN: xDSL+POTS+SkyLife Cable: Cable internet+VoIP+Broadcasting
Technologies for Internet QoS Speed up & Over-provisioning (QoS-Free) - Current BE service - Applicable to any kind of future applications * Almost zero delay if link speed is in the order of 10s of Mbps Service Differentiation for Priority Traffic SP, CBQ, Hybrid - Wired network: IETF DiffServ + MPLS (Priority service +Tunneling) Priority: EF > AF > BE - Wireless ad hoc network: SWAN (Feedback control + CAC) Priority: rt traffic > BE traffic Policy-based QoS Guarantee - Policies for service differentiation / BW allocation / scheduling / routing
Policy-based QoS Framework of TEQUILA Static policy (Long-term) Dynamic policy (Short-term) Policy Manageme nt Tool Policy server Policy consumer SLS Subscr. SLS Inv. Traffic Estimation Network monitoring Network Provisioning Resource manag. Route manag SLS Management Performance Manag. Traffic Engineering Policy management SLS Req. From Custome r
NTT RENA’s QoS Framework RENA TM : Resilient Network Architecture SCS: Session control server BB: Bandwidth broker PS: Policy-server NIB:Network information base BB Video server Web server PCPC Phon e PSTN PCPC SC S NIBService/Network Control Platform Separation of control and data transfer plane Flexible network control Centralized QoS management e2e QoS From NMS PS e2e Optical network
Policies for IP QoS Principle for IP QoS: Be faithful to IP’s philosophy. - Advantage of IP: Connectionless paradigm Simple & scalable IP QoS Provisioning: via Policy-based networking - Destination-based routing based on OSPF principle - Treat QoS traffic with higher priority than the BE traffic SP does not sacrifice the lower class traffic when the link speed exceeds 10s of Mbps!! - Protection of QoS traffic: Class-based CAC - Network–wide: Interoperation of Policy Server/NMS Dynamic CAC & bandwidth management
Policy-based Networking: Big Picture Core node: DiffServ-based CBQ + PHB-based Scheduling + MPLS-TE Edge node: SLA negotiation, UPC, Packet classification /QoS mapping, CBQ, Packet- scheduling Voice buffer PBX VoIP G/W Phones Access Router Bandwidth Broker Voice Data VPN Core Route r Access network PCs/Phones/TEs/Serv ers MPLS Tunnel Premium backbone network AN Router QoS Server (SLA) PCs/Servers … Policy Base Traffic meter NIB Best effort IP network Policy server farm Current
Packet Level SLS Service type AttributesApplication services QoS Requirements (ITU-T) Data service Conventional BE service Email, ftp, low quality video None Voice service QoS compatible to PSTN Internet telephony, Interactive multimedia E2E delay < 150ms for 99.99% of packets, PLR < 10 -3 Video service New TV, Videoconfere ncing E2E delay < 150ms for 99.99% of packets, PLR < 10 -4 Bundle service Interactive IP VPN,www, on-line game, streaming multimedia Minimum contracted BW, E2E delay < 1~4sec PLR < 10 -6
Mapping between DiffServ & MPLS QoS Services Premium service Assured service Better than BE service Best-Effort service DiffServ PHB EFAF 1/2AF 3/4BE MPLS Label PlatinumGoldSilver/ BronzeSteel ITU-T QoS Class 0/123~45 Typical Applications VoIP VPN Signaling, VoD WWW, telnet, streaming service e-mail
Bandwidth Allocation Alternatives Bandwidth reservation model - Absolute QoS guarantee - Low efficiency - e.g.: IntServ architecture - Application to: Videophone service Bandwidth share with priority scheme model - Statistical QoS guarantee - High utilization - e.g.: DiffServ architecture - Application to: Multi-service
Bandwidth Reservation Model : Videophone Service Architecture C v =C C: Number of videophone connection (channel) : Bandwidth of a videophone connection E-S/W Video Phone Router LAN IP Network (DiffServ) C v = ? Internet traffic CdCd … … ISP E-S/W
Input to The System Parameters: Number of subscribers: M (Tens of thousand) Fraction of active connections at busy hour: (10%~20%) Mean session duration: 1/ ( 1,000seconds) Mean session arrival rate: (0.01 ~ 1 ) Session broking probability: (0.5~1%) Bandwidth requirement of a Videophone session: = 2Mbps (For basic rate service) (8bits/pixel 250 200pixels/frame 5frames/sec=2Mbps)
Analytic System Model Assumption on the session: Session arrival: Poisson arrival Session duration: Exponential distribution System model: Infinite number of traffic sources Full availability link M/M/c/c Queuing model with C concurrent channels Erlang B-formula for GoS of videophone service Constraint on the Service level: E(C, ) . where = (M / )/3600
Results and Discussion Typical Assumptions: M = 30,000 residential subscribers = 0.1 (Residential= 10%, Business=20%) 1/ =1,000 seconds =0.36/0.72 sessions / Busy hour / Person (Residential / Business) =1% = 2Mbps (basic rate) Result of computation: Input traffic in Erlang: 300 Erlang Computed number of channel: 323 Channels Required bandwidth: C v =C = 323 2Mbps = 646Mbps To provide the safety margin, we have to take into account the traffic from alternate route of the neighboring nodes: C v Final = 2 C v =1.3Gbps Final result.
Comparison: Residential vs. Business When the subscribers are business customers - = 0.2 - = 0.72 (The offered load increases to 4 times that of the residential subscribers!) Total required bandwidth for a number of subscribers: Number of subscriber Required number of channel (residential / business) Total Required Bandwidth (residential / business) 30,000323 / 12921.3 / 5.2 Gbps 60,000650 / 26002.6 / 10.4 Gbps 90,000928 / 37123.7 / 14.8 Gbps
Bandwidth Share Model : Strict Priority Scheduling Scheme System model: DiffServ-aware MPLS Service model: Strict priority (SP) to voice over data1 over data2 Router model: M/G/1 queue with non-preemptive service Objectives: Evaluation of delay for class1, 2, and 3 packets Our concern: 1. Can we apply the SPSS in a DiffServ router for BcN? 2. How about the behavior of delay with respect to the system parameters? Voice packet Data1 packet SP C Data 2 packet
System Model System parameters: - Mean arrival rate for voice/data1/data2: 1, 2, 3 - Mean service time for voice/data1/data2 : 1/ 1, 1/ 2, 1/ 3 - Second moment of service time: E[ k 2 ],k=1,2,3 - Offered load for voice/data1/data2 : 1, 2, 3 - Link capacity: C Source models: - Voice: Poisson arrival, fixed packet size - Data1 & data2: Poisson arrivals, Pareto distributions
Delay Performance Mean waiting times for M/G/1 queue with SP service: Mean waiting time for M/G/1 queue with FIFO service: R R C S 2 =squared coefficient of variation for service time of a packet
Waiting Time of Voice Packets for Different Link Capacities m2=500bytes, m3=1500bytes Under SP scheduling scheme, delay of voice packet is almost negligible for high-speed links!
Waiting Time of Voice Packets for Different Service Schemes The conventional wisdom of “SP isolates voice traffic from non- voice traffic” does not hold! This is more evident for the WFQ-families. m2=m3=1,000 bytes, C=1Mbps
Delay Performance of Data Traffic Performance comparison between different classes: 1 =0.2 1 =0.4 2 =0.2 2 =0.4 1 =0.2
Summary Policy is important for QoS provisioning in future Internet. Network provisioning is dependent on the policy. Reservation model over-estimates the network resources. Shared bandwidth model will prevail. Accurate dimensioning of network resources saves cost.
References [Lee] Hoon Lee, “Strategies for the construction of Policy-based managed IP QoS”, Final Report of NCA II-RER-04041, November 30, 2004. [Lee] Hoon Lee et al., “Dimensioning NGN for QoS guaranteed voice services”, Jr. of IEEK, Vol. TC-40, No.12, December 2003. [Lee] Hoon Lee, “Delay analysis of DiffServ/MPLS network”, Industrial Mathematics Initiative 2004, August 26-28, Korea. [Lee] Hoon Lee et al., “Delay performance of non-real- time services for the strict priority scheduling scheme”, Jr. of the research institute of industrial technology, Vol.18, May 2004. [Trimintzios] P. Trimintzios et al., An architectural framework for providing QoS in IP differentiated services networks, TEQUILA Project report.