CPSC Topics in Multimedia Networking A Mechanism for Equitable Bandwidth Allocation under QoS and Budget Constraints D. Sivakumar IBM Almaden Research Center Sreenivas Gollapudi Oracle Corporation / SUNY at Buffalo The Twelfth IEEE International Workshop on Quality of Service IWQoS, Presented by: Abdul Hasib CPSC Topics in Multimedia Networking

Quality of Service (QoS) –Integrated Service –Differentiated Service Objective and previous work Desired Properties Basic principle Bandwidth allocation algorithm Comparison parameter Experimental Results Presentation outline

CPSC Topics in Multimedia Networking Quality of Service (QoS) Internet provides “Best effort” service –Simple –No admission control –No guarantee; no performance assurance –Single level of service –Not suitable for booming real time applications. The capability to provide resource assurance and service differentiation in a network is often referred to as quality of service (QoS).

CPSC Topics in Multimedia Networking Technologies QoS parameters –Throughput; Delay; Jitter; Data corruption etc. Developed technologies categorized by two key QoS issues: –Resource allocation Integrated Service Differentiated Service –Performance optimization Multiprotocol label switching (MPLS) Traffic engineering

CPSC Topics in Multimedia Networking Integrated Services (Int-serv) Per-flow resource reservation. Steps: –Application requests its required resource. –The network uses a routing protocol to find a path based on the requested resources. –Reservation protocol (RSVP) is used to install the reservation state along that path. –At each hop, admission control checks whether sufficient resources are available to accept the new reservation. –After reservation, the application can start to send traffic over the path for which it has exclusive use of the resources.

CPSC Topics in Multimedia Networking Int-serv (cont.) Two services level –guaranteed (delay) service, controlled load service.

CPSC Topics in Multimedia Networking Int-serv (cont.) Disadvantage: –Applicable to long lasting traffic (video conferencing); –Scalability problem may not be able to cope with a very large number of flows at high speeds requires the support of accounting and settlement between different service providers Potential Application Area: –IP telephony, video conferencing over corporate intranets

CPSC Topics in Multimedia Networking Differentiated Service (Diff-serv) Uses a combination of edge policing, provisioning, and traffic prioritization to achieve service differentiation. Resource allocation to aggregated traffic rather than individual flows. Traffic policing on the edge and class-based forwarding in the core. Ingress Edge Router Egress Edge Router Interior Router

CPSC Topics in Multimedia Networking Router Functionality Interior routers: traffic classification and forwarding  use DSCP as index into forwarding table Network edge routers: Packet classification: service level agreement (SLA) and traffic type. Responsible for mapping packets to their appropriate forwarding classes, per-hop behavior (PHB). Each PHB is represented by a 6 bit DSCP Set DSCP in packet header DS field, modified TOS field. Nonconforming traffic may be dropped, delayed, or marked with a different forwarding class.

CPSC Topics in Multimedia Networking Router Functionality (cont.) Network edge routers: traffic conditioning (policing, marking, dropping), SLA negotiation.

CPSC Topics in Multimedia Networking Diff-serv Define forwarding behavior not end-to-end services. Guarantee by provisioning rather than reservation: –For each forwarding class, the amount of traffic that users can inject into the network is limited at the edge of the network. service providers can adjust the level of resource provisioning; control the degree of resource assurance to the users. Qualitative QoS scheme.

CPSC Topics in Multimedia Networking Quality of Service (QoS) –Integrated Service –Differentiated Service Objective and previous work Desired Properties Basic principle Bandwidth allocation algorithm Comparison parameter Experimental Results Presentation outline

CPSC Topics in Multimedia Networking Objective and previous work Fair and efficient bandwidth management. Allocation based on differential pricing scheme. Previous work Allocation is based on a single preferred bandwidth (A) request of user. Uniform allocation rule: –Initially allocate an equal share (X) to every user, –if A<X, user will receive exactly A. –Excess bandwidth will be equally re-apportioned among all remaining users.

CPSC Topics in Multimedia Networking Desired properties Feasibility: ; a i =allocated bandwidth to user i Efficiency: –If the sum of ideal allocations exceeds the supply, then no user should receive more than his ideal allocation; –if supply exceeds the sum of ideal allocations, then no user should receive less than his ideal allocation. Strategy proof ness: Mis-reporting bandwidth requirement should not give incentive to user. Envy-freeness: When the allocations have been determined, no user would prefer other users allocation to his.

CPSC Topics in Multimedia Networking Basic principle Network coordinator – is used to deploy the bandwidth allocation mechanism in a general network; –handles the functions of admission control. Bandwidth allocation is based on: –Service provider (vendor) parameter Cost function, c(b)= ; = constant Capacity and utilization information of all links along path, P.

CPSC Topics in Multimedia Networking Basic principle (cont.) Bandwidth allocation is based on: –User (agent) parameter: Utility function, Pricing level, l i - User can choose to pay more for a QoS requirement to increase the likelihood of receiving the better service. - where, c i = cost function for agent I C= revenue goal

CPSC Topics in Multimedia Networking Utility function

CPSC Topics in Multimedia Networking Bandwidth allocation algorithm (M)

CPSC Topics in Multimedia Networking Bandwidth allocation algorithm (M) (cont.)

CPSC Topics in Multimedia Networking Bandwidth allocation algorithm (M) (cont.)

CPSC Topics in Multimedia Networking Comparison parameter (1) Quality of Service: For an agent with optimal allocation, an allocation b of bandwidth is defined to achieve a QoS value of Q(, b) = b/ (2) Probability of allocation: Fraction of agents who receive at least, their minimum acceptable allocation ( ). (3) Fairness rank, F(i) is proportional to

CPSC Topics in Multimedia Networking Fairness rank vs. QoS

CPSC Topics in Multimedia Networking Fairness rank vs. Probability of allocation

CPSC Topics in Multimedia Networking Thank you