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A Mechanism for Equitable Bandwidth Allocation under QoS and Budget Constraints. Sreenivas Gollapudi Oracle Corporation / SUNY at Buffalo. D. Sivakumar IBM Almaden Research Center. Presented by: Abdul Hasib CPSC 601.43 Topics in Multimedia Networking . - PowerPoint PPT Presentation
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CPSC 601.43 Topics in Multimedia Networking
A Mechanism for Equitable Bandwidth Allocation
under QoS and Budget Constraints
D. Sivakumar IBM Almaden Research Center
Sreenivas GollapudiOracle Corporation /
SUNY at Buffalo
The Twelfth IEEE International Workshop on Quality of Service IWQoS, 2004.
Presented by:Abdul Hasib
CPSC 601.43 Topics in Multimedia Networking
CPSC 601.43 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 601.43 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 601.43 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 601.43 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 601.43 Topics in Multimedia Networking
Int-serv (cont.)
• Two services level– guaranteed (delay) service, controlled load service.
CPSC 601.43 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 601.43 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.
IngressEdge Router
EgressEdge Router
Interior Router
CPSC 601.43 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 601.43 Topics in Multimedia Networking
Router Functionality (cont.)
Classifier MarkerShaper/Dropper
Meter
Traffic conditioning
• Network edge routers: • traffic conditioning (policing, marking, dropping), SLA negotiation.
PHB group
dataPHB class
real-timePHB class
PHB 11
PHB 22
PHB 21
low delay
highimportance
high delay
lowimportance
CPSC 601.43 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 601.43 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 601.43 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 601.43 Topics in Multimedia Networking
Desired properties• Feasibility: ; ai=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.
iia B
CPSC 601.43 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.
b
CPSC 601.43 Topics in Multimedia Networking
Basic principle (cont.)• Bandwidth allocation is based on:
– User (agent) parameter:• Utility function,
• Pricing level, li - User can choose to pay more for a QoS requirement to
increase the likelihood of receiving the better service. - where, ci= cost function for agent I
C= revenue goal
iu (b) : [0,B] 0
*
1
: minimum acceptable bandwidth;
: optimal bandwidth;
: maximum acceptable bandwidth
i
i
i
i ic (l, b) = l b,
iil B C
CPSC 601.43 Topics in Multimedia Networking
Utility function
, ( ) ( ) ( , )i i i iwelfare w b u b c l b
CPSC 601.43 Topics in Multimedia Networking
Bandwidth allocation algorithm (M)
CPSC 601.43 Topics in Multimedia Networking
Bandwidth allocation algorithm (M) (cont.)
CPSC 601.43 Topics in Multimedia Networking
Bandwidth allocation algorithm (M) (cont.)
CPSC 601.43 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
*
**
00i
il
CPSC 601.43 Topics in Multimedia Networking
Fairness rank vs. QoS
CPSC 601.43 Topics in Multimedia Networking
Fairness rank vs. Probability of allocation
CPSC 601.43 Topics in Multimedia Networking
Thank you