korea advanced institute of science and technology network systems lab. 1 dual-resource tcp/aqm for...
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Korea Advanced Institute of Science and Technology
Network Systems Lab.
Dual-resource TCP/AQM for processing-constrained
networks
INFOCOM 2006, Barcelona, Apr. 25, 2006
Minsu Shin and Song ChongDepartment of EECS,
KAIST, Korea
Injong RheeDepartment of CS,
NC State Univ., USA
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Network Systems Lab.
OutlineMotivation
Processing-constrained networkDual-resource environment
ObjectiveDual-resource fair allocationDual-resource TCP/AQM (DRQ)
DRQ objectiveDRQ implementation
Simulation resultsConclusion
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Network Systems Lab.
Processing-constrained networkLink bandwidth grows fast
Advancement in optical network technology Over-provisioning as the solution to congestion
The rise of in-network applications
IP forwarding
Packet classification and filteringNetwork address translation
Web-switchingVPN & IPSec
Data TranscodingDuplicate data suppression
Firewall
Complexityincreases
Traditional network
Future network
Virus detection
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Network Systems Lab.
Dual-resource environmentBoth bandwidth and CPU can be a bottleneck
Can existing congestion control (TCP) be applied?
CPUSwitch
User
Malicious userCongestion
What is fair and efficient resource allocation?
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Network Systems Lab.
ObjectiveTo propose a dual-resource fairness criteria
Extend the proportional fairness to the dual-resource environmentProvide fair and efficient resource usages
To propose a dual-resource queue (DRQ)Active queue management (AQM) strategy Approximate dual-resource fairness for TCP sourcesScalable : Not maintaining per-flow states or queuesIncrementally deployable : No changes in TCP stacks
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Network Systems Lab.
Single-resource fairnessOnly considering link bandwidth constraint
Assume that network consists of L links
Ss
ss rU )(maximize
LlBr lS(l)s
s
,
tosubject
Maximization problem
rate r1
TxTxOutput
Link
Bl (Mbps)rate rS
)1(1)1(lim
)log(a
sa
s
s
ra
r
r
)( ss rU
maximum throughputproportionalfair
max-min fair
Selection of [Mo 00]
[Low 99]
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Network Systems Lab.
Dual-resource fairnessConsidering both CPU and bandwidth constraint
Network consists of L links and K CPUs
TxTxCPUCPUOutput
Link
C (cycles/sec) B (Mbps)
rate r1
rate rS
Ss
ss rU )(maximize
LlBr
KkCrw
lS(l)s
s
kS(k)s
sks
,
,
tosubject
Maximization problem
ksw : processing density
Indicating required CPUcycles per bit
)log( ss r
)( ss rU
Proportional fairness is weight of flow s
Selection of
s
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Network Systems Lab.
PerformanceSingle link case
Dual-resource fair allocationSingle-resource fair allocation
TxTxCPUCPUOutput
Link
C (cycles/sec) B (Mbps)
rate r1
rate r4
w = [1, 2, 4, 8]
40% utilization increasesCPU fair share
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Network Systems Lab.
Dual-resource fair rateCongestion price of resources
CPU price : θ, Link price : πIncreasing : demand > resource capacityDecreasing : demand < resource capacityPositive when the resource becomes a bottleneckZero when not a bottleneck
Fair rateInversely proportional to the aggregate price
)()( sLl lsKk k
ks
ss
wr
Weighted CPU price sum Link price sum
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Network Systems Lab.
Dual-resource TCP/AQMExtend dual-resource fairness to TCP network
DRQ modifies RED algorithmTxTx
B1 (Mbps) C2 (cycles/s)
TxTx
B3 (Mbps)
p2Packet drop with probability p1
p3
CPUCPU
TCP Sender (w) TCP receiver
TCP Sending rate ≈ α
321 ppp Current TCP/AQM
TCP Sending rate ≈ α
321 ppwp Our Goal
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Network Systems Lab.
DRQ algorithm
TxTx
B1 (Mbps) C2 (cycles/s)
TxTx
B3 (Mbps)
p2packet drop with probability p1
p3
CPUCPU
TCP Sending rate ≈ α
2231 pwpp
Our Goal
Xpwpppwpp 23
22
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2321 )()(
Each resource drops packet with p2 (link), or (wp)2 (CPU)
)22()22()22( 323121 pwpppwppX
Communication between resources is needed
TCP Sender (w) TCP receiver
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Network Systems Lab.
DRQ algorithm
32321 22222 pwppwppX
At link 1, mark packet with prob. 12pAt CPU 2, mark packet with prob.
22wpAt link 3, mark packet with prob. 32p
If already marked, then drop packet!
(link), or (CPU) : Intra-marking probability
p2 (link), or (CPU) : Inter-marking probabilitywp2
2p 2)(wp
No explicit communication between resources!
Red card!
Yellow card!
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Network Systems Lab.
DRQ-ECN implementationThree ECN cases
ECN = 00 : Initial stateECN = 10 : Signaling-marked
(No congestion notification)ECN = 11 : Congestion-marked
(TCP source decreases its window size by half)
DRQ’s ECN marking algorithmWhen a packet arrives
if(ECN ≠ 11) set ECN to 11 with red-card probabilityif(ECN == 00) set ECN to 10 with yellow-card probabilityif(ECN == 10) set ECN to 11 with yellow-card probability
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Network Systems Lab.
Performance evaluationComparison partners
RED-RED : CPU and link queues use original RED
Very cheap. Most of current network system architecture
DRR-RED : Scheduling CPU using per-flow queue
Expensive approach. Similar architecture to current computing system
TxTxCPUCPUOutput
Link
C (cycles/sec) B (Mbps)
RED RED
TxTxCPUCPUOutput
Link
C (cycles/sec) B (Mbps)
REDDRR
DRQ’s complexity : RED-REDbut,DRQ’s performance : DRR-RED
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Network Systems Lab.
Single CPU and link case
Topology
DRQ
In DRQ, each follows fair rates.
40 TCP sources, which require different processing(0.25, 0.50, 1.00, 2.00)
Varying CPU capacity
Average throughput of each source
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Network Systems Lab.
Single CPU and link case
Comparison of bandwidth utilization
RED-RED has much lower bandwidth utilizationDRQ performance is comparable to DRR-RED
Efficiency improves !
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Network Systems Lab.
Impact of high processing flows
Insert a few high processing flows(w=10.0)
DRQ and DRR-RED prevent their domination but RED-RED doesn’t
Prevent CPU domination!
Increase total throughput
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Network Systems Lab.
Multiple-link simulation(1)
Throughput of TCP/DRQ in multiple link simulations
Parking-lot topology, with various cross-traffic
DRQ follows theoretic fair rates very well.
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Network Systems Lab.
Partial deploymentNetwork edge
Pushing complicated tasks to the edge of InternetDRQ can be initially deployed to the edge system
Simulation topology
DRQ is implemented at only IE1 and EE1
Source groups
SG1 : High processingSG2 : low processing
Others : Negligible processing
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Network Systems Lab.
Partial deployment
Throughput of processing-constrained edge
Increase throughput of IE1
Partial deployment is also beneficial to improve efficiency
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Network Systems Lab.
ConclusionContribution of this paper
Finding an efficient and fair allocation policy in the dual-resource environmentSuggestion of the practical implementation guideline
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Network Systems Lab.
References[Kelly 98] “Rate control in communication networks: shadow prices, proportional fairness and stability", J. of the Operational Research Society, 1998
[Mo 00] “Fair end-to-end window-based congestion control", IEEE/ACM TON 2000
[Wolf 00] “Commbench – a telecommunications benchmark for network processors", ISPASS 2000
[Low 99] “Optimization flow control I : Basic algorithm and convergence", IEEE/ACM TON 1999
[Floyd 93] “Random early detection gateways for congestion avoidance", IEEE/ACM TON 1993
[Low 03] “A duality model of TCP and queue management algorithms", IEEE/ACM TON 2003
[Pappu 02] “Scheduling processing resources in programmable routers”, IEEE INFOCOM 2002