Energy aware networking

Energy awarenetworking

Vincenzo DeMaio

Introduction

Link levelapproachesSleeping mode

Energy EfficientEthernet

Rate Adaptation

ProxyingapproachesNIC proxying

External proxying

InfrastructurelevelapproachesEnergy aware routing

Energy awareapplicationsGreen TCP/IP

Green bittorrent

Conclusions

Energy aware networking

Vincenzo De Maio1

1Distributed and Parallel SystemsUniversitaet Innsbruck

13/06/2012 / Masterseminar 2


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Introduction

Volume of CO2 emissions produced by ICT sector is anapproximate of 2%

Actual power usage in the U.S. network infrastructure isbetween 5 and 24 TWh/year


Vincenzo DeMaio

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Green bittorrent

Conclusions

Figure: Energy consumption of network devices


Vincenzo DeMaio

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Energy aware networking research

Link Level approaches

Proxying approaches

Infrastructure level

Energy aware applications


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions



Proxying approaches




Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions



Proxying approaches




Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions



Proxying approaches




Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Outline

1 Link level approachesSleeping modeEnergy Efficient EthernetRate Adaptation

2 Proxying approachesNIC proxyingExternal proxying

3 Infrastructure level approachesEnergy aware routing

4 Energy aware applicationsGreen TCP/IPGreen bittorrent

5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Outline





5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Outline





5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Outline





5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Outline





5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

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Outline





5 Conclusions


Vincenzo DeMaio

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Green bittorrent

Conclusions

How to take the sleep decision?

For how long?

Which routers are the most amenable to sleeping?


Vincenzo DeMaio

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For how long?



Vincenzo DeMaio

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Green bittorrent

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For how long?



Vincenzo DeMaio

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What we expect

Figure: A sleep-mode approach


Vincenzo DeMaio

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Conclusions

On-off algorithmNotations

B : the output buffer size at the upstream interface.

w : the number of the most recent inter-arrival times.

λ : the mean inter-arrival time

τ = αB is the buffer occupancy threshold, α < 1 (authorsuse α = 0.1 in their experiments)

m is the number of packets in the buffer

δ is the time required for the transition between on/off andresynchronization


Vincenzo DeMaio

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Conclusions

On-off algorithmAlgorithm

If link is activeif m > τ , then do not sleepif m ≤ τ then, ensure with a high probability that the totalnumber of packets n + m < αB. Thus, if X1,X2, ...Xn arerandom variables for consecutive inter-packet times thenX = ΣXi has a Gamma distribution1. We find maximum tsuch that, P[X > t]≥ 0.9if t > δ then the link is put in sleep mode for timemin{t−δ , tmax} where tmax is the maximum amount of timethat the link can be put to sleep. The sleep time is transmittedto the downstream interface in an 802.3 frame.

If downstream interface is in sleep state and the sleepingtimer is expiring

if m = 0 and t > δ , then the upstream interface sends another802.3 frame packet to the downstream interface to sleep fortime min{t−δ , tmax}.

1Assuming that inter-arrival time are IID random variables


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions







Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

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Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

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Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

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Vincenzo DeMaio

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Rate Adaptation


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Green bittorrent

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Vincenzo DeMaio

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Green bittorrent

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Outline





5 Conclusions


Vincenzo DeMaio

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Energy efficient ethernet

Figure: Energy Efficient Ethernet


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Energy Efficient EthernetImportance of Refresh signal

1 Ensure that both partners know that the link is present andallows for immediate notification following a disconnection.

2 Can be used to test the channel and create an opportunity forthe receiver to adapt to changes in the channel characteristics


Vincenzo DeMaio

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5 Conclusions


Vincenzo DeMaio

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Rate adaptation

Use the existing ethernet data rates

Find a tradeoff between packet delay and time spent in lowestrates.


Vincenzo DeMaio

Introduction



Rate Adaptation


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Green bittorrent

Conclusions

Rate adaptationProblems

How to choose the right moment to adjust the link ratedown/up in order to minimize the packet drops?

Which is the correct rate that gives us the energy-savingopportunity without degrading the link performance?

How do we negotiate the rate?


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Rate adaptation

1. if (link data rate is high)2. if (queue length is less than low queue threshold)3. if (link utilization is less than link utilization threshold)4. set the link data rate to low5. else6. if(link data rate is low)7. if(queue length is greater than high queue threshold)8. set the link data rate to high


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Further considerations

We need to synchronize the link terminations

For rate adaptation, we need faster handshake

Many works seems to prefer the sleeping mode solutionbecause of his lower complexity


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

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Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Content inspection

A pattern matching technique

Matches packet payloads against a set of pre-definedsignatures

Useful also in network security context


Vincenzo DeMaio

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Green bittorrent

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Content inspection





Vincenzo DeMaio

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Content inspection





Vincenzo DeMaio

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5 Conclusions


Vincenzo DeMaio

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Rate Adaptation


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Green bittorrent

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NIC ProxyingThe main idea

NIC may drop the chatter and handle the traffic requiringminimal computation

Main system will be woken up only when non-trivial packetscome


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

NIC ProxyingThe main idea

NIC may drop the chatter and handle the traffic requiringminimal computation

Main system will be woken up only when non-trivial packetscome


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Outline





5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

External proxying

Offloading traffic filtering and processing to an externalmachine instead that on the NIC

Can act for a number of end-devices

Can also maintain TCP connectivity for idle hosts

Problem: unicast communication


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

External proxying






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

External proxying






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

External proxying






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



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Outline





5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Energy Aware Routing Problem

ERP-1: Assume there is a tuple of input parameters, (G,T ,K )Where

G denotes the topology of data center network,

T denotes the traffic matrix

K denotes the predefined threshold of network throughput.

1 L(R1) = minL(R),R ∈ R+

2 M(R1)≥ K

R+ is the space of all possible routings for T

L(R1) denotes the number of switches involved in R1

M(R1) is the network throughput of T under R1.


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

An heuristic solution

Route Generation: Select the routing for each flow in trafficmatrix so that the network throughput is as high as possible.They select the path with the fewest overlapping flows overthe bottleneck link in the path.

Throughput Computation: The module of throughputcomputation is to calculate the network throughput in a giventopology.

Switch Elimination: A greedy algorithm for the eliminationprocess. First, they compute the traffic carried by each activeswitch in topology G, which is the total throughput of flowstraversing the switch. Then, they select the active switchescarrying the lightest traffic.


Vincenzo DeMaio

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Rate Adaptation


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Green bittorrent

Conclusions

An heuristic solutionThe algorithm

HRA(G0, T, PR)begin1 set G := G0;2 //Route Generation3 set R := RG(G, T);4 //Throughput Computation5 set Tht1:= TC(G, T, R);6 do begin7 //eliminate the switches carrying the lightest traffic8 set G := SE(G, T, R);9 set R := RG(G, T);10 set Tht2:= TC(G, T, R);11 set P := Tht2 / Tht1;12 end while(P>=PR )13 return (R, G);End


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Problem: Robustness of the network. . .

What happens in case of hardware failures?


Vincenzo DeMaio

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Outline





5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Green TCP/IP

In TCP/IP, when a connection is dropped, every resourcededicated to the connection is cleaned up.

A client cannot go to sleep without dropping its connection

Idea: add a new option to TCP communicating to the serverour intention to sleep


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Green TCP/IP





Vincenzo DeMaio

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Green TCP/IP





Vincenzo DeMaio

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Figure: A green TCP/IP


Vincenzo DeMaio

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5 Conclusions


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Main issues

A client should be able to sleep whenever it is donedownloading and has no current upload requests pendingfrom its peers independent of how many TCP connections itmay have to other peers.

When a peer sleeps, it must not affect its state in the peerlists of other peers

An awake peer must always have a sufficient number of otherpeers that are awake to download from

A peer must be able to wake-up sleeping peers in a controlledfashion.


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Main issues






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

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Main issues






Vincenzo DeMaio

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Rate Adaptation


External proxying



Green bittorrent

Conclusions

Main issues






Vincenzo DeMaio

Introduction



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Green bittorrent

Conclusions

Unknown: a peer that has been given to this peer by thetracker, and it is unknown if the peer is sleeping or awake.

Connected: a peer that this peer has an active TCPconnection with. File pieces can be uploaded anddownloaded on the connection.

Sleeping: a peer that has disconnected its TCP connectionwith this peer. The TCP connection must be re-establishedbefore file pieces can be uploaded or downloaded.


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Event 1: Detection of TCP disconnect of a peer1. on (detection of TCP disconnect of peer p)2. p.state = sleepingEvent 2: Time out of connection timer1. on (timeout of connection timer)2. check with tracker for new peers as needed3. for (all new peers in peer list)4. p.state = unknown5. while (count of connected peers < max\_connect)6. p = randomly selected peer in my peer list7. if (have tested all peers) exit this loop8. if (wake-up condition == true)9. send wake-up message to peer p10. try to connect to peer p11. if (TCP connection established)12. p.state = connected13. else14. remove peer p from my peer list15. restart connection timer


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Event 3: Timeout of inactivity timer

1. on (timeout of inactivity timer)2. send not interested message to connected peers3. send choke message to connected peers4. close all of my TCP connections5. my.state = sleeping6. enter sleep state

Event 4: Detection of my wake-up triggered by peer p

1. on (detection of my wake-up triggered by peer p)2. if (TCP connection is established from peer p)3. my.state = connected4. send my file contents bitfield to peer p5. run choking algorithm


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

ConclusionsLink level approaches

IEEE standardization committee has already proposed a draft

They will be included in Energy Efficient Ethernet

Could be interesting to evaluate the benefits on a larger scale


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

ConclusionsProxying approaches

Several prototypes are currently in development

Standardization efforts are also ongoing

We need a deep analysis about effects on QoS


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions






Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

ConclusionsInfrastructure approaches

Reducing number of active devices is not the best solution

Multiple robustness and connectivity issues

We need further investigations in modeling and find a goodtradeoff


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

ConclusionsSoftware level

TCP/IP will be beneficial for every software relying on it.

Higher level approaches like green bittorrent seems alsopromising

Main lack in this area is about existing tools


Vincenzo DeMaio

Introduction



Rate Adaptation


External proxying



Green bittorrent

Conclusions

Questions?


Vincenzo DeMaio

Introduction



Rate Adaptation


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Green bittorrent

Conclusions

Thanks for your attention!

Technology

Energy aware networking