An Energy Efficient Internet:An Energy Efficient Internet

An Energy Efficient Internet:An Energy Efficient Internet: Ongggoing Work Ken ChristensenKen Christensen Department of Computer Science and Engineerin...

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An Energy Efficient Internet: Ongoing g g Work Ken Christensen Department of Computer Science and Engineering University of South Florida Tampa, p , FL 33620 [email protected] This material is based upon work funded by the National Science Foundation under grant CNS-0520081.

Slide 1 of 38 ciscoGreen07.ppt (March 5, 2008)

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

The project htt // http://www.csee.usf.edu/~christen/energy/main.html f d / hi t / / i ht l

Focus is on edge devices, not on Internet core or data centers (servers). The edge consumes more energy than data centers. Key collaborator is Bruce Nordman from LBNL.

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Where this talk is going • Reducing direct energy use • Reducing induced energy use • Some additional efforts Direct energy gy use = energy gy used byy network links and equipment (routers, switches), but not end devices. Induced energy use = Increment for higher power state of devices needed to maintain network connectivity connectivity. Slide 3 of 38

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Reducing energy use of links • Observation #1: Most edge links are lightly utilized – 1% to 5% on average

• Observation #2: Higher rates consume more power – About 2 to 4 W for 1 Gb/s versus 100 Mb/s – Much more for 10 Gb/s versus 1 Gb/s

• Idea: Match link data rate with utilization • Key issue: Time to change between data rates – Can buffer overflow occur during transition? – What impact might this packet loss have?

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Ethernet Adaptive Link Rate (ALR) • Two parts to the problem 1) Mechanism for how to switch link rate 2) Policy for when to change link rate switch

link

desktop PC

A ppolicyy based on buffer thresholds low high low high g

packets k t

packets buffer thresholds in the switch port Slide 5 of 38

buffer thresholds in the PC NIC

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Ethernet ALR • We published the idea and some results – From a 2005 paper and a 2006 whitepaper

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Work done by other people… • ALR found its way into an IEEE 802.3 study group – Mike Bennett from LBNL as chair

• Got named “Energy Efficient Ethernet” • Became Rapid PHY Selection (RPS) • Much discussion on switching times • Much work on mechanisms • Some work on policies – Myy students and I did work here Slide 7 of 38

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

IEEE 802.3az task force htt // http://www.ieee802.org/3/az/index.html i 802 /3/ /i d ht l

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Some press and a logo…

* Logo by Glen Kramer of Teknovus, Inc. (full permission for use granted via email dated January 27, 2007) Slide 9 of 38

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

*

Where is EEE now… • EEE is moving forward to becoming a standard – PAR was approved in fall 2007 – 2009 timeline for f completion – Is in EPA Energy Star Version 5.0 Draft 1 for computers

• Current proposal is for “Active-Idle” approach Active-Idle Idle idea is from Intel • Active – – – –

Use a low-power idle between packets Switch to high data rate when a packet is queued Can stay in high data rate if desired About 10 microseconds to transition out of low-power idle

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Active--Idle… Active • Slide from November 2007 802.3az meeting…

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

EEE could enable deeper savings • Greater savings than from link and PHY/MAC – Savings within switches, routers, and servers

• Can a reduced link data rate allow for… – Powering-down g of components? p – Clocking-down of components?

• Is some sort of signaling needed to control transition time of link data rate?

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

What is next? • EEE requires both ends to participate – Full EEE deployment is still many years off

• Can we do something simpler? – Something backwards compatible?

• Idea: PAUSE Power Cycle (PPC) – Use PAUSE to proactively cycle links on and off – During link off time power-down LAN switch

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

PAUSE Power Cycle (PPC) • Basic idea is to periodically send PAUSE frames – Power “stuff” down during PAUSE interval edge router Internet LAN switch PAUSE frames (sent periodically)

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Packet loss is possible here

During PAUSE off time LAN switch powers down

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

PPC parameters • Key parameters – toff = time off (the PAUSE quanta time) – ton = time on – D = duty cycle

D=

t on t on + t off

t on

D ⋅ t off = 1− D

• Time between PAUSE frames is ton + toff

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Does PPC work? • We have emulated PPC in a test bed – Test bed looks sort of like the previous figure – Use a PC C to send PAUSE S packets through a repeater – All links were 100 Mb/s



Used human subjects to assess effects – For file transfer, web surfing, and real-time video – Subjective j evaluation ((MOS score approach) pp ) • Rating from 5 (excellent) to 1 (unacceptable)

• Real time video was 10 frames/sec ((about 1 Mbps) p ) – Axis 2100 camera

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

PPC evaluation • Experimented with 50% duty cycle – toff = 50, 100, and 300 milliseconds – ton= toff

• Seven human subjects (all students) • For web browsing toff = 50 ms toff = 100 ms toff = 200 ms

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MOS score of 4.2 MOS score of 3.9 MOS score off 3 3.1 1

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Not really sure what this means /

PPC evaluation continued • For real time video – toff = 50 and 100 ms had no problems! – toff = 300 ms had some problems (t ( off > interframe f time))

Artifact

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

PPC next steps • Better evaluation – Better user study (look for just noticeable thresholds) – Measure packet loss at edge router in test bed – ns2 simulation for larger and more realistic networks

• Explore an adaptive policy – Change toff and/or ton based on utilization?

• Explore external switch wake-up – Use Magic Packet from “overflowing” device to switch?

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Where this talk is going • Reducing direct energy use • Reducing induced energy use • Some additional efforts

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Reducing energy use of edge devices • Observation: Devices are often left fully poweredon to maintain network connectivity or presence – Usually devices are not in active use

• Idea: A low-power p network connectivity yp proxy y – Maintains full network connectivity for a sleeping device – Enable devices to sleep more often – Not related to existing Wake-on-LAN Wake on LAN

• Key issues: Lots of issues… – Definition of “connectivity” connectivity – Wake-ups (not too many, not too few) – Packet loss (during wake-up)

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Network connectivity proxy • Proxy covers for sleeping device – Proxy could be in local NIC or in the network desktop PC

Steps:

(1)

1) PC determines it is time to sleep 2) PC state transferred to proxy (2)

(5)

network t k

3) PC sleeps, sleeps proxy maintains presence 4) Proxy determines need to wake-up PC 5) PC awakes and proxy state transferred

(3) proxy

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(4)

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Network connectivity from the EPA • Future EPA Energy Star Program Requirements – Version 5.0, Draft 1* (for computers)

“Computers p must maintain full network connectivity while in Sleep mode, according to a platform-independent industry standard.”

* From http://www.energystar.gov/index.cfm?c=revisions.computer_spec Slide 23 of 38

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Key protocols that proxying might cover • Layers 1 and 2 – Already covered by PHY/MAC

• Layer 3 – ARP, ND, ICMP, IGMP, IPSec, etc.

• Layer 4 – TCP connection request (SYN) – TCP connections (keep-alives)

• Higher layers – NetBIOS, SMB, DHCP, SNMP, SSDP, VPN, SSH, etc. – Application semantics

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Proxying at higher layers • Need to support network applications • Two examples: 1)) Proxying y g standard for low p power UPnP • UPnP uses distributed discovery (SSDP) • SSDP is lightweight

2) Current work in proxying for P2P • P2P has lots of query traffic, but downloads are rare • Query traffic is lightweight

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Proxying for UPnP – standard • UPnP Low Power Architecture (from UPnP Forum) – Version 1.0, August 28, 2007

“UPnP Basic Power Management g Proxy: y This node will act on behalf of sleeping devices and make sure that the devices are di discoverable bl if they h are in i low l power state. This node will store methods for waking the UPnP Low Power devices devices.”

* From http://www.upnp.org/specs/lp/UPnP-lp-Architecture-v1-SDCP-20070828.pdf Slide 26 of 38

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Proxying for P2P – in the lab • Approach #1 for Gnutella – Move query handling to microcontroller when PC sleeps – Wake-up PC C when a G GET comes in

desktop PC TCP connections to P2P neighbors

NetBurner microcontroller

State and wake-up signal TCP connections to P2P neighbors

proxy Slide 27 of 38

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Proxying for P2P – in the lab continued • Approach #2 for Gnutella – Permanently split query handling and file storage – Query Q handling always running in a smaller device – Use a shared drive in PC and wake-up when needed desktop PC

A Napster-like approach can be more energy efficient!

Access to shared drive in PC and wake-up signal TCP connections to P2P neighbors query handler Slide 28 of 38

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Proxying for reducing energy use • Started to think about proxying 10 years ago – Now hoping to define a direction towards a standard

Proxying of ARPs to maintain reachability.

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

What is next? • Can “intelligence” in the network help the edge? • Explore making power state of edge devices known • Idea: Support in first first-level level LAN switch – – – – – –

Not age-out entries in ARP cache for sleeping PCs Filter packets to eliminate spurious wake-ups Reply to simple protocols Generate packets for simple protocols Wake-up PC when appropriate Maybe even assist applications to sleep

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Proxying in a switch • Can a switch filter packets for a sleeping PC? – Use existing packet inspection capabilities

• Can a switch assist applications in a sleeping PC? – Monitor email, twitter, IM, RSS feeds, etc. – Wake-up PC when something interesting happens Email server

Monitor my feeds Wake-up

twitter.com

desktop PC Internet first-level LAN switch Slide 31 of 38

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Web server (RSS)

Where this talk is going • Reducing direct energy use • Reducing induced energy use • Some additional efforts

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

SNMP Power MIB • We want to expose and control power state • Can we use SNMP to do this? • Developing a Power MIB for desktop PC – – – – – – –

Power management capabilities Power management settings Total time for idle, idle busy busy, and sleep Current elapsed time for idle, busy, or sleep Statistics on wake-up events (network, user, etc.) Statistics on sleep events Actual power and energy use if a meter is installed?!

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Green telnet • Telnet (SSH, etc.) ties state to TCP connection – This effectively prevents client from going to sleep

• Can we disconnect and buffer data in the server? • Developing a gtelnetd and client for Linux – Server buffers data when clients goes to sleep – Client reconnects when it wakes-up wakes up – Server delivers buffered data when client reconnects

• Working on an article for Dr Dr. Dobbs Journal

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Adaptive power management for PCs • PC operating systems use inactivity time-out – For example, to put system to sleep – Use a fixed f value for f time-out

• Can we do better with an adaptive time-out? • Have experimented with using past activity history – Adaptively set the time-out time out value based on prediction – No conclusive results yet – Need to do more characterization of PC users

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Summary • Energy savings can be enabled by the network

– Direct energy savings • Matching link data rate to link utilization

How can we exploit this for deeper savings? – Induced energy savings • Letting devices sleep without losing network presence

How can we enable this for all end devices?

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Acknowledgments • Folks who contributed… – – – – – –

Bruce Nordman Francisco Blanquicet Miguel Jimeno Jakob Klamra Jeremy Blackburn Others

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Some of my students

Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Questions? Ken Christensen Department of Computer Science and Engineering University of South Florida Tampa, FL 33620 [email protected] usf edu [email protected]

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA

Key links •

Project website – http://www.csee.usf.edu/~christen/energy/main.html



Project publications and invited talks –

http://www.csee.usf.edu/~christen/energy/pubs.html



ALR whitepaper at Ethernet Alliance – http://www.ethernetalliance.org/technology/white_papers/alr_v10.pdf



Proxying whitepaper at Ethernet Alliance –



IEEE 802.3az taskforce –



http://www.ethernetalliance.org/technology/white_papers/Proposal_for_Proxying_edit.pdf

http://www.ieee802.org/3/az/index.html

UPnP Forum Low Power V 1 1.0 0 –

http://www.upnp.org/specs/lp.asp

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Cisco Green Research Symposium – March 5-6, 2008 San Jose, CA