Wireless Data Center Network. Reporter: Green

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Wireless Data Center Network

Reporter: Green

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Outline

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What is DCN?

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Challenges in current DCN

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Cable

–

Topology

–

Traffic load

•

Heterogeneous DCN

–

Optical DCN

–

Wireless DCN

•

Challenges in WCDN

•

The researches in WDCN

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What is DCN?

http://www.dotblogs.com.tw/regionbbs/archive/2011/10/08/ithome.article.contest. day3.cloud.infrastructure.aspx

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What is DCN?

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What is DCN?

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What is DCN?

Cui. Y, Wang, H. Cheng, X. Chen, B. “Wireless data center networking”, Wireless Comm., IEEE, 2011

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What is DCN?

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What is DCN?

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Data Center Requirements

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High inter-node link capacity

• Bandwidth-demanding operations: E.g., GFS

• Distributed processing of large amounts of data: E.g., MapReduce

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Reliability

• Provision sources to meet the requirements of DCN

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Security Isolation

• Data exchanged between services in DCN must be isolated

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Scalability

• Link connectivity should scale to support large numbers of machines

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Small form factor of networking components:

• Higher processing requirements • Floor space constraints

• Reduced energy consumption

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K. Ramachandran et al. “60 GHz data-center networking: Wireless=>worry less?”, Technical report, NEC, 2008

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Challenges in Current DCN

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By the year of 2014

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Google has got over 900 000 servers in its 30 data

centers

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For traditional schemes

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Expensive high-end switches and a large number

of wires

Facts and Stats of World’s largest data centers

http://storageservers.wordpress.com/2013/07/17/facts-and-stats-of-worlds-largest-data-centers/

Yong Cui, Hongyi Wang, Xiuzhen Cheng, “Channel Allocation in Wireless Data Center Networks”, INFOCOM , 2011

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Challenges in Current DCN

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High maintenance challenges

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Cabling complexity

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Cables take up space

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Hard to keep accurate per-cable info

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Inefficient cooling

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Under raised floors

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Airflow blockages

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Substantial operational costs

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7-8% of the total infrastructure cost

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Challenges in Current DCN

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Challenges in Current DCN

Katayama, Y. ; Takano, K. ; Kohda, Y. ; Ohba, N. ; Nakano, D., ”Wireless data center networking with steered-beam mm wave links”, WCNC, 2011

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S. Kandula, J. Padhye, and P. Bahl. “Flyways to de-congest data center networks.” In HotNets, Nov. 2009

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Challenges in Current DCN

S. Kandula, J. Padhye, and P. Bahl. “Flyways to de-congest data center networks.” In HotNets, Nov. 2009 – relieve hotspot and boost performance

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D. Halperin, S. Kandula†, J. Padhye†, P. Bahl†, and D. Wetherall,” Augmenting Data Center Networks with Multi-Gigabit Wireless Links”, SIGCOMM, 2011

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Heterogeneous DCN

G. Wang, David G. Andersen, Michael K, Konstantina Papagiannaki, T.S. Eugene Ng, Michael Kozuch, Michael Ryan, ”c-Through: part-time optics in data centers”,

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Heterogeneous DCN

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Farrington, N., et al. “Helios: A hybrid lectrical/optical switch architecture for modular data centers.” In Proc. Of SIGCOMM (2010).

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Heterogeneous DCN

Katayama, Y. ; Takano, K. ; Kohda, Y. ; Ohba, N. ; Nakano, D., ”Wireless data center networking with steered-beam mm wave links”, WCNC, 2011

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Heterogeneous DCN

Cui. Y, Wang, H. Cheng, X. Chen, B. “Wireless data center networking”, Wireless Comm., IEEE, 2011

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The Researches in WDCN

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The technologies used in WDCN

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802.11

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802.15.3c

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Introduction of Wireless Technology

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Introduction of Wireless Technology

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http://electronicdesign.com/communications/what-s-difference-between-wireless-hd-and-80211ad-60-ghz-technologies

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The Researches in WDCN

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The Researches in WDCN

S. Kandula, J. Padhye, and P. Bahl. “Flyways to de-congest data center networks.” In HotNets, Nov. 2009 – relieve hotspot and boost performance

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Introduction -WDCN

WDCN

Hardware

Design

Resource

Allocation

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[1] K. Ramachandran et al. “60 GHz data-center networking: Wireless=>worry less?”, Technical report, NEC, 2008. (凱旭)

[2] S. Kandula, J. Padhye, and P. Bahl. “Flyways to de-congest data center networks.” In HotNets, Nov. 2009 – relieve hotspot and boost performance (凱旭)

[3] Vardhan, H. ; Thomas, N. ; Seong-Ryong Ryu ; Banerjee, B. ;Prakash, R., “Wireless Data Center with Millimeter Wave Network”, GLOBECOM, 2010

[4] D. Halperin, S. Kandula†, J. Padhye†, P. Bahl†, and D. Wetherall,” Augmenting Data Center Networks with Multi-Gigabit Wireless Links”, SIGCOMM, 2011(于翔)

[5] Katayama, Y. ; Takano, K. ; Kohda, Y. ; Ohba, N. ; Nakano, D., ”Wireless data center networking with steered-beam mm wave links”, WCNC, 2011

[6] W. Zhang, X. Zhou, L. Yang, Z. Zhang, B. Y. Zhao, and H. Zheng. ”3D Beamforming for Wireless Data Centers”. HotNets, 2011 (凱程)

[7] Yamane. T., katayama. K., “An effective initialization of interference cancellation algorithms for distributed MIMO systems in wireless datacenters”, GLOBECOM, 2012

[8] Katayama, Y. ; Yamane, T. ; Kohda, Y. ; Takano, K. ;Nakano, D. ; Ohba, N. ”MIMO link design strategy for wireless data center applications”, WCNC, 2012

[9] Xia Z., Zengbin Z., Yibo Z., Yubo Li, Saipriya Kumar,. Amin Vahdat, Ben Y., “Mirror Mirror on the Ceiling: Flexible Wireless Links for Data Centers”, SIGCOMM, 2012 (凱程)

[10] Shin, J.-Y. ; Sirer, E.G. ; Weatherspoon, H. ; Kirovski, D., ”On the Feasibility of Completely Wireless Datacenters”, Networking, IEEE/ACM Transactions on, vol. PP, no. 99, 2013

Hardware

Design

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[1] Cui. Y, Wang, H. Cheng, X. Chen, B. “Wireless data center networking”, Wireless Comm., IEEE, 2011 (專題生)

[2] Cui. Y, Wang, H. Cheng, X., “Wireless Link Scheduling for Data Center Networks”, ICUIMC, 2011(凱程)

[3] Cui. Y, Wang, H. Cheng, X., “Channel allocation in wireless data center network”, INFOCOM, 2011

[4] Cui. Y, Wang, H. Cheng, X., Li, D. Ylä-Jääski, A., “Dynamic Scheduling for Wireless Data Center Networks”, Parallel and Distributed Systems, IEEE Transactions on, vol. PP, no. 99, 2013 (凱旭)

Scheduling by traffic load:

- The heuristic algorithm (by distance) - Min-Max Scheduling (by distance) - Genetic Algorithm

(by interference && transmitting speed)

The data traffic in ToR switches is heavy and may cause serious degradation in network performance

Resource

Allocation

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Suitability of 60 GHz radios

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Spectrum availability

– License-free 60 GHz range (57- 64 GHz)

– 70 orthogonal channels

• 1GHz = 10 channels (100MHz per channel)

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Improved interference mitigation and security

– Path loss attenuation due to low frequency

– Highly directional beams with small footprints

• Small λ and more # of antennas in a phased array

– 𝐿𝐿𝐿𝐿𝑛𝑛𝐿𝐿_{𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤} = 𝐿𝐿𝐿𝐿𝑛𝑛𝐿𝐿_{𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤} (less than 15゜)

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Scalability

– Scale DCN connectivity

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Small form-factors

– E.g., UWB (3.1 to 10.6GHz) requires 30cm x 30cm form factor

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Universal operation

– License-free in many countries

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Vardhan, H. ; Thomas, N. ; Seong-Ryong Ryu ; Banerjee, B. ;Prakash, R., “Wireless Data Center with Millimeter Wave Network”, GLOBECOM, 2010

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Challenges of 60 GHz radios

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Characters of 60 GHz

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Travel shorter distances

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Suffer significant attenuation from obstacles

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Small

λ

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Challenges of 60 GHz

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Lower bandwidth in practice

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Lower reliability

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High propagation loss and attenuation

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One of solution:

– High transmit powers, but power consumption ↑

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Challenges in WDCN

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How to determine the best beam to communicate with?

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TX

• Use feedback channel info to form beams off-line

• Use a table-lookup at runtime

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RX

• Estimate the channel from TX

• Feedback channel info to TX

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How often to carry out channel measurements?

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For beam forming

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Use the same beam in TX and RX?

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Need a suitable algorithm in DCN

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Map receiver feedback to antenna patterns?

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Dynamic channel fluctuations

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People walking within in DCN

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Challenges in WDCN

Yamane. T., katayama. K., “An effective initialization of interference cancellation algorithms for distributed MIMO systems in wireless datacenters”, GLOBECOM, 2012

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Wireless Data Center

Katayama, Y.,Yamane, T., Kohda, Y., Takano, K., Nakano, D., Ohba,N.,

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Wireless Data Center

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Wireless Data Center

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Challenges in WDCN

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How to compute multi-hop routes ?

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By two arbitrary nodes that cannot be directly connected

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How to handle node and link failures?

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How to choose the optimal path

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Distribute the traffic for load balancing?

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Do nodes need to maintain multiple paths

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TXs deal with small time-scale channel fluctuations?

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How much do reflectors help improve link reliability?

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Is there an optimal placement of reflectors

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The Reaserches in WDCN

Vardhan, H. ; Thomas, N. ; Seong-Ryong Ryu ; Banerjee, B. ;Prakash, R., “Wireless Data Center with Millimeter Wave Network”, GLOBECOM, 2010

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The Researches in WDCN

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Xia Z., Zengbin Z., Yibo Z., Yubo Li, Saipriya Kumar,. Amin Vahdat, Ben Y., “Mirror Mirror on the Ceiling: Flexible Wireless Links for Data Centers”, SIGCOMM, 2012

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The Researches in WDCN

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Shin, J.-Y. ; Sirer, E.G. ; Weatherspoon, H. ; Kirovski, D., ”On the Feasibility of

Completely Wireless Datacenters”, Networking, IEEE/ACM Transactions on, vol. PP, no. 99, 2013

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The Researches in WDCN

Shin, J.-Y. ; Sirer, E.G. ; Weatherspoon, H. ; Kirovski, D., ”On the Feasibility of

Completely Wireless Datacenters”, Networking, IEEE/ACM Transactions on, vol. PP, no. 99, 2013

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http://storageservers.wordpress.com/2013/07/17/facts-and-stats-of-worlds-largest-data-centers/

Konstantina Papagiannaki,

http://electronicdesign.com/communications/what-s-difference-between-wireless-hd-and-80211ad-60-ghz-technologies

Vardhan, H.

Seong-Ryong Ryu

Prakash, R.

T.

. Ylä-Jääski, A.