Towards an Towards an Application-Aware Application-Aware Multicast Multicast Communication Communication Framework for Framework for Computational Grids Computational Grids M. M M. M AIMOUR AIMOUR , C. P , C. P HAM HAM RESO/LIP, UCB Lyon RESO/LIP, UCB Lyon ASIAN'02, Hanoi ASIAN'02, Hanoi Dec 5th, 2002 Dec 5th, 2002
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Towards an Application-Aware Multicast Communication Framework for Computational Grids
Towards an Application-Aware Multicast Communication Framework for Computational Grids. M. M AIMOUR , C. P HAM RESO/LIP, UCB Lyon ASIAN'02, Hanoi Dec 5th, 2002. Computational grids. application user. from Dorian Arnold: Netsolve Happenings. The current usage of grids. Mostly - PowerPoint PPT Presentation
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Towards an Application-Aware Towards an Application-Aware Multicast Communication Multicast Communication
Framework for Computational Framework for Computational GridsGrids
M. MM. MAIMOURAIMOUR, C. P, C. PHAMHAM
RESO/LIP, UCB LyonRESO/LIP, UCB Lyon
ASIAN'02, HanoiASIAN'02, Hanoi
Dec 5th, 2002Dec 5th, 2002
Computational gridsComputational gridsapplication user
from Dorian Arnold: Netsolve Happenings
The current usage of gridsThe current usage of grids
Encyclopedia of Life Project…)Encyclopedia of Life Project…)
– Distributed Data Mining (seti@home…)Distributed Data Mining (seti@home…)
– Data and code transfert, massively parallel job Data and code transfert, massively parallel job submissions (task-farm computing)submissions (task-farm computing)
Protocol with modular services for achieving Protocol with modular services for achieving reliability, scalability and low latenciesreliability, scalability and low latencies
global NACKsuppression
Early PacketLoss Detection
Local
Recoveries
DynamicReplierElection
AccurateCongestion
Control
subcast ofrepair
packets
Ex: Ex: Global NACKs suppressionGlobal NACKs suppression
The repair latency can be reduced if the lost packet could be requested as soon as possible
These NACKs are ignored!
core networkGbits/s rate
active router active router
active router
sourcesource
Internet Data Center
application-aware component
computing center
computing center
campus/corporate
The AAC associated to the source can perform early processing on packets. For instance the DyRAM protocol uses subcast and loss detection services in order to reduce the end-to-end latency.
In DyRAM, any recei-ver can be designated as a replier for a loss packet.The election service is performed by the upstream AAC on a per-packet basis. Having dynamic repliers allows for more scalability as caching within routers is not required.
An AAC associated to a tail link performs NACK aggregation, subcasting and the election on a per-packet basis of the replier.
Deploying reliable multipoint Deploying reliable multipoint data distribution servicesdata distribution services
Local recovery & replier electionLocal recovery & replier election
Local recoveries Local recoveries reduces the end-to-reduces the end-to-end delay end delay (especially for (especially for high loss rates and high loss rates and a large number of a large number of receivers).receivers).
#grp: 6…24
4 receivers/group
p=0.25
Local recovery & replier electionLocal recovery & replier election
As the group size As the group size increases, doing the increases, doing the recoveries from the recoveries from the receivers greatly receivers greatly reduces the reduces the bandwidth bandwidth consumptionconsumption
48 receivers distributed in g groups #grp: 2…24
Early Packet Loss ServiceEarly Packet Loss Service
p=0.25
#grp: 6…244 receivers/group
EPLD is very beneficialto DyRAM
DyRAM implementation DyRAM implementation
TAMANOIR active execution environmentTAMANOIR active execution environment Java 1.3.1 and a linux kernel 2.4Java 1.3.1 and a linux kernel 2.4 A set of PCs receivers and 2 PC-based A set of PCs receivers and 2 PC-based
Data packets are 4 KBytesData packets are 4 KBytes
testbed configurationtestbed configuration
The data pathThe data path
IP UDP S,@IP data
ANEP packet
IP
UDP
S,@IP dataTamanoir portFTP port
S
TAMANOIRTAMANOIR
S1
FTPFTP
Cost of Data Packet ServicesCost of Data Packet Services
ike
resama
resamo
resamdstan
Cost of Data Packet ServicesCost of Data Packet Services
NACK: 135μsNACK: 135μs DP : 20μs if DP : 20μs if
no seq gap, no seq gap, 12ms-17ms 12ms-17ms otherwise. otherwise. Only 256μs Only 256μs without timer without timer settingsetting
Repair: 123μsRepair: 123μs
Cost of Replier ElectionCost of Replier Election
ike
resamo
NACK
The election is performed on-the-fly.
It depends on the number of downstream links.
Costs range from 0.1 to 1ms for 5 to 25 links per router.
Cost of Replier ElectionCost of Replier Election
Conclusions (1)Conclusions (1)
Grids can be more than end-host computing Grids can be more than end-host computing resources interconnected with network linksresources interconnected with network links
High-bandwidth links is not enough to High-bandwidth links is not enough to provide E2E performances for distributed, provide E2E performances for distributed, interactive applicationsinteractive applications
Application-aware components can be Application-aware components can be deployed to host high-value servicesdeployed to host high-value services
In-network processing functions can make In-network processing functions can make grids more responsive to applications' needsgrids more responsive to applications' needs
Conclusions (2)Conclusions (2)
The paper shows how an efficient The paper shows how an efficient multipoint service can be deployed on an multipoint service can be deployed on an application-aware infrastructureapplication-aware infrastructure
Simulations and experimentations shows Simulations and experimentations shows that low latencies can be obtained with the that low latencies can be obtained with the combination and collaboration of light and combination and collaboration of light and simple servicessimple services