Self-Organized Resource Allocation in LTE Systems with Weighted Proportional Fairness
Weighted Fairness Performance Scenarios - IEEE 802 · Weighted Fairness Performance Scenarios...
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Weighted Fairness Performance Scenarios Khaled Amer AmerNet IEEE 802.17 Plenary Meeting Vancouver, BC, Canada July 2002
Transcript of Weighted Fairness Performance Scenarios - IEEE 802 · Weighted Fairness Performance Scenarios...
Weighted FairnessPerformance Scenarios
Khaled AmerAmerNet
IEEE 802.17 Plenary MeetingVancouver, BC, Canada
July 2002
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Background
• RAH/FAH adhoc decided that it would bebeneficial to have an annex with scenariosthat may have fairness/performance issues
• Only some of these scenarios are presentedhere, others are in annex J
• Can be used as implementation guidelines
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Objectives
• Identify scenarios that may havefairness/performance implications
• Show the ideal target for a fairnessmechanism
• Show the effect of not having a fairnessmechanism as well as potential fairnessproblems
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Convention Used
Ideal Target
Potential problem
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Parking Lot Scenario #1
s1 s3 s4 s5 s6 s7 s8s2
flow[1,5]
flow[2,5]
flow[3,5]
flow[4,5]
25%
25%0%
0%
25%0%
25%100%
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Parking Lot Scenario #1 ...
• Concern:
– Station #1 consumes total BW
• Solution:
– Throttle upstream node using fairnesscontrol messages
• Applicable:
– Addressed by single choke and multi-choke fairness algorithms
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Parking Lot Scenarios #2
s1 s3 s4 s5 s6 s7 s8s2
flow[1,5]
flow[2,5]
flow[3,5]
flow[4,5]
25%
25%50%
25%
25%12.5%
25%12.5%
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Parking Lot Scenario #2 ...
• Concern:
– Station #1 is overly restricted
• Solution:
– Have fairness algorithm divide BWevenly between upstream stations
• Applicable:
– Addressed by single choke and multi-choke algorithms
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Parallel Parking Lot
s1 s3 s5 s6 s7 s8s2
flow[2,6]
flow[3,6]
flow[4,6]
flow[5,6]flow[2,3]
25%
25%
25%
s4
75%
25%
0%
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Parallel Parking Lot ...• Concern:
– Flow [2,3] is restricted by congestion on link [5,6]
• Solution:
– Have fairness algorithm provide congestion info andhop-count to congestion point
– Provide support for VDQ for various hop-countdistances
• Applicable:
– When hop count is not reported
– Addressed by single choke and multi-chokealgorithms with VDQ
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Multi-flow Parking Lot
• Illustrates support of weighted fairnesswith aggregate flows
s1 s3 s5 s6 s7 s8s2
flow[1,5]
flow[2,5]
flow[3,5]
flow[4,5]
s4
flow[4,6]
flow[4,7]
flow[4,8]
25%
25%
6.25%
14%25%14%
25%14%
14%6.25%
14%6.25%
14%6.25%
14%
56%
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Multi-flow Parking Lot ...
• Concern:
– Flows from node 4 get more than 25% BW whichconflicts with source-based fairness
• Solution:
– Have fairness algorithm provide source-based fairness
• Applicable:
– Addressed by single choke and multi-choke algorithms
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Dual Exit Parking Lot
• Illustrate effect of having multiple chokepoints on the ring
s1 s3 s5 s6 s7 s8s2
flow[2,5]
flow[3,5]
s4
flow[2,7]
flow[3,7]
flow[4,7]
flow[5,7]
flow[6,7]
20%
20%
20%
20%
40%
20%0%
20%
20%
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Dual Exit Parking Lot ...
• Concern:
– Flows traversing through link [4,5] are overlythrottled because they only observe congestion onlink [6,7]
• Solution:
– All stations should be made aware of all chokepoints and not just the worst one
• Applicable:
– Problem occurs with single choke fairness algorithm
– Solved using multi-choke fairness algorithm
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Choked high/low BW pair
• Illustrates potential for oscillations
BA
s1 s3 s5 s6 s7 s8s2 s4
flow[1,8]95% (steady state)
flow[5,8] 5%50% (average worst case)
choke
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Choked high/low BW pair …(Ramp time dominates prop time)
A'sallowed rate
A is periodically shutoff by B and has toramp all the way up
Time
BW
use
d by
A
5%
95%
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Choked high/low BW pair ...
• Concern:
– Flows from node 1 are unnecessarily throttled in acyclical fashion which reduces BW utilization
• Solution:
– A solution is to have fairness algorithm provideinformation about the whole ring, and react based onring conditions
• Applicable:
– Problem occurs with aggressive mode
– Worst case occurs with two stations far apart
IEEE 802.17 Plenary MeetingVancouver, BC / July 2002 ka_scen_02.pdf
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Conclusions
• These scenarios (and others) arerecommended by the RAH/FAH to beadded as informative text in Annex J tohelp understand the implications ofvarious fairness algorithms
• Behavior of fairness algorithms need tobe simulated to demonstrate how theyoperate in these scenarios
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