A City Traffic Model for Optical Circuit Switching in Data Centers

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All in One Slide

1. Traffic has changed into a mix of extremes → the hotspot model 06◦ BigData, bulk transfer, migration in clouds 03, traffic blackswans...

2. Current bestOBS 10 → a mix of OPS + OCS (... to mirror the traffic)

◦ easier to separate into two separate networks3. Bulk transfers want e2e cut-through 16 ... and will not settle for less

◦ good solutions are likely to drastically change the technology

06 myself+1 "Popularity-Based Modeling of Flash Events in Synthetic Packet Traces" IEICE CQ研 (2012)

03 myself+0 "Optimizing Virtual Machine Migration for Energy-Efficient Clouds" IEICEJ (2014)

10 Harry G. Perros "Connection-Oriented Networks : SONET/SDH, ATM, MPLS, and Optical Networks" Wiley (2005)

16 "Cut-Through and Store-and-Forward Ethernet Switching for Low-Latency Environments" Cisco (2014)

M.Zhanikeev -- [email protected] -- A City Traffic Model for Optical Circuit Switching in Data Centers -- http://bit.do/marat141030 -- 2/24...

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Cut-Through


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The Benefits of Cut-Through• Cut-Through mode is possible only during exclusive access to line 11 16

• applies to all technologies but OCS -- assuming networks are all-IP today

• in Ethernet, available even in the cheapest switches

C: Cut Through

Check, etc. Q: Queue

D: Drop QoS classes

11 G.Wang+5 "c-Through: Part-time Optics in Data Centers" ACM SIGCOMM (2010)



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Cut-Through will not Work when Shared• again, in Ethernet, optical, wireless networks, you always share theuplink

• cut-through does not work when shared• ... therefore, circuits have to be emulated 11

Switch Switch

Qualitatively Identical



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Cut-Through: Parallel vs Sequential

20 24 28 32 36 40Transfer time in contention (s)

20

24

28

32

36

40Tr

ansf

er ti

me

by e

xclu

sive

circ

uits

(s)


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OBS


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Optical Burst Switching (OBS) Basics

10 Harry G. Perros "Connection-Oriented Networks : SONET/SDH, ATM, MPLS, and Optical Networks" Wiley (2005)

15 R.Jankuniene+1 "The Contention Resolution in OBS Network" Elektronika ir Electrotechnika (2014)


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OBS: Specific Slow-Downs

1. the OEO bottleneck, which requires gaps between signaling and bulk◦ an intrinsically centralized design

2. fixed configuration: time gaps, burst size, backoff timeouts, etc.◦ when not fixed --QoS classes are difficult to implement in a fair manner

3. no official way to communicate with NOC -- OBS is an isolated world4. ...


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The City Traffic Model


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The City Traffic Model

.The Basic Idea is Simple.....

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... let's treat packet traffic the same way we treat road traffic in ourcities

• bulk sources are unique individuals, just like drivers◦ 3C games apply (3C: cogn., coop, coord)

• the concept of highways = tall roads is applicable◦ there should be a cost threshold for bulk transfers

• before getting on the highway, bulk sources should be able to make a decision:go on highway or stay on free roads


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TE Formulations• a non-standard TE 12

• unit demand as source s,dest d, volume v, time t,wavelength λ

Ti = ⟨s, d, v, t⟩.

• notation: demand →solution

Overlaps

• Traditional OSPF

Ti = ⟨s, d, v⟩ → ⟨s, a, b, ..., d⟩

• Optical without Wavelength Switchign

Ti = ⟨s, d, v⟩ → ⟨s, λ⟩

• Optical with Switching

Ti = ⟨s, d, v⟩ → ⟨s, λs, λa, λb, ...⟩

• The City Traffic Model

Ti = ⟨s, d, v, t1, t2⟩ → ⟨s, λ, t⟩

12 B. Fortz+1 "Internet Traffic Engineering by Optimizing OSPF Weights" INFOCOM (2000)


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The Model: Bulk, Tall Gates, Sensing• distributed, heterogeneous, bulk transfer circuits• one-way, so, sensing and admission on one side is enough


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Sensing: More Like Wireless

• OBS implements collission control, sometimes called sensing 15

• real sensing exists in Wireless MAC• the same concepts are used here:

1. too much sensing is bad interference2. pull versus push approaches, depending on environment3. physically separate signaling from bulk domains

15 R.Jankuniene+1 "The Contention Resolution in OBS Network" Elektronika ir Electrotechnika (2014)


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Simulation


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The Hotspot Traffic Model.Hotspots are..

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...bulk (BigData, blackswan) sources which are very few but veryimpact-y.

• standard traffic modelsdo not capture hotspots

• 4 states: normal vshotspots, hotspots arebaseline vs FlashCrowds

• parameters: magnitude,variance across hotspots,likelihood of a Flash event, ...


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Current Solutions/Technologies

• very hard to convert symbolics into numbers


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Numeric Models

• all the above metrics are converted into numeric form (seconds, impairmentratio, ...)◦ all realistic based on the literature, more in the paper or in 01

• continuous versus once-per-flow metric

• bulks of various levels, input based on the hotspot model• input: 100 flows, output: which model finishes first

01 myself+0 "Circuit Emulation for Big Data Transfers in Clouds" Networking for Big Data, Wiley (in print) (2015)


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Performance Results

0 2 4 6 8Ordered list

0

0.45

0.9

1.35

1.8

2.25

log(

dur

atio

n)

Do Nothing Network VirtualizationTraditional SchedulerP2Px1N P2Px2N Tall Gate


0

0.8

1.6

log(

dur

atio

n)


0.6

1.2

1.8

2.4

log(

dur

atio

n)


1.5

1.8

2.1

2.4

log(

dur

atio

n)


1.65

1.95

2.25

2.55

log(

dur

atio

n)


1.2

1.6

2

2.4

log(

dur

atio

n)

Size: 10M..100M Size: 100M..500MSize: 500M..1G

Size: 10G..100GSize: 1G..10G Size: 10G..50G

2.4

• Tall Gate = City Traffic(two codenames)

• do nothing is OK forsmall bulks

• Tall Gate wins for allthe large bulks


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Implementation


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The City Traffic Model in Practice

Gate A

Gate B • shows JGN (NICT) -- inprocess of getting access totwo gates now

• logically a ring, physically atrunk

• gates fit perfectly asaccess points in/out of JGN


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OCS with Gates and Sensing• a lot more responsive NOC as part of sensing technology

• dumb, cheap, e2e OCS network


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Wrapup

• City Traffic (aka Tall Gate) Model works for all networks -- wireless,Ethernet, optical

• search for similar solutions already ongoing in data centers 16, some withFCoE 09

• some related ideas applied to optical networks in data centers 11

• but this presentation is the first to present the actual model

• more details later in 01


09 S.Gai "Data Center Networks and Fibre Channel over Ethernet (FCoE)" Lulu.com (2008)


01 myself+0 "Circuit Emulation for Big Data Transfers in Clouds" Networking for Big Data, Wiley (in print) (2015)


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That’s all, thank you ...


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[01] myself+0 (2015)Circuit Emulation for Big Data Transfers in CloudsNetworking for Big Data, Wiley (in print)

[02] myself+0 (2014)Multi-Source Stream Aggregation in the CloudAdvanced Content Delivery ... in the Cloud, Wiley

[03] myself+0 (2014)Optimizing Virtual Machine Migration for Energy-Efficient CloudsIEICEJ

[04] myself+0 (2014)High Availability Cloud Storage ... Social Graph, Throughput...IEICE NS研

[05] myself+1 (2012)Analytical Models for L2 versus L3 QoS ProvisioningIEICE PN研


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[06] myself+1 (2012)Popularity-Based Modeling of Flash Events in Synthetic Packet TracesIEICE CQ研

[07] myself+0 (2013)....Measuring Per-Packet Cost of Software Defined NetworkingIEICE SC研

[08] J.McDonald (1983)Fundamentals of Digital SwitchingApplications of Communications Theory, Springer

[09] S.Gai (2008)Data Center Networks and Fibre Channel over Ethernet (FCoE)Lulu.com

[10] Harry G. Perros (2005)Connection-Oriented Networks : SONET/SDH, ATM, MPLS, and Optical NetworksWiley


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[11] G.Wang+5 (2010)c-Through: Part-time Optics in Data CentersACM SIGCOMM

[12] B. Fortz+1 (2000)Internet Traffic Engineering by Optimizing OSPF WeightsINFOCOM

[13] I.Houidi+2 (2008)A Distributed Virtual Network Mapping AlgorithmICC

[14] Hui Zang+4 (2001)Dynamic Lightpath Establishment in Wavelength-Routed NetworksIEEE ComMag

[15] R.Jankuniene+1 (2014)The Contention Resolution in OBS NetworkElektronika ir Electrotechnika

[16] (2014)M.Zhanikeev -- [email protected] -- A City Traffic Model for Optical Circuit Switching in Data Centers -- http://bit.do/marat141030 -- 24/24

...

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Cut-Through and Store-and-Forward Ethernet Switching for Low-LatencyEnvironmentsCisco

[17] (2003)Definitions of Managed Objects for the Optical Interface TypeRFC3591

[18] (current)INCITS T11 Standardization Bodywww.t11.org/FCoE


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Technology

A City Traffic Model for Optical Circuit Switching in Data Centers