interconection networks

8/8/2019 Interconection Networks

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Interconnection Networks and

Clusters

by

Onur OzyerSchool of Electrical Engineering and Computer Science

University of Central Florida


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Outline Interconnection Networks

Network Topology

Centralized Switching

Distributed Switching

Clusters

Case Study: Google Case Study: Cluster Project at UCF

References


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Interconnection Networks Connection of components within a computer.

Connecting computers to build information

network.

Interconnection Network

End Users

Interconnection Network

End Users

Internetworking


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Interconnection NetworksMessage

Bandwidth = Propagation rate to the link

Transmission Delay = Message Size / Bandwidth

Propagation Delay: Time to propagate over the link

Total Delay = Processing Delay + Transmission

Delay + Propagation Delay

Header Data Check Sum


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Interconnection Media Twisted Pair wires

Level 3 ~ 10 Mbit/s

Level 5 ~ 100 Mbit/s Cat 5 ~ 1000 Mbit/s

Coaxial cable ~ 10 Mbit/s

Fiber optics ~100 Mbit/s

1Gbit/s (one way) Light Source, laser diode or LED

Fiber optic cable

Light detector


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Network Topology- Centralized

SwitchingA) Crossbar Topology: Any

node connected to any

node. (Fully connected) n2 switches.

Low Contention.

a) Source Routingb) Destination Routing

P0

P1

P2P3


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Network Topology - Switch

Boxes

Straight Swap Lower

Broadcast

Upper

Broadcast


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SwitchingB) Omega Network:Nodes

connected to switch boxes.

Each switch box has 4switches.

Less switch (n/2 lgn)

More contention

(blocking)

P0

P1

P2

P3


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SwitchingC) Fat Tree:Nodes and switches form a tree.

Bandwidth is added higher in the tree.

Multiple paths (load balance, failure recovery)

Doubling nodes need one more level of switches

Switches

End Users


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Network Topology- Distributed

SwitchingDistributed Switching: Each node has own switch

Ring Network: Sequence of nodes connected

together. Average message delay: n/2 switches.

Simultaneous message transfer on the ring.

Token rings


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Switching

2D Grid 3D Cube

d-dimensional array

n = k d-1 X ...X kO nodes

described by d-vector of coordinates (id-1, ..., iO) d-dimensional k-ary mesh: N = kd

k = dN

described by d-vector of radix k coordinate

d-dimensional k-ary torus (ork-ary d-cube)?

2D Torus


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Network Topology - Hypercubes Also called binary n-cubes. # of nodes = N = 2d.

O(logN) Hops

Good bisection BW

Complexity

Out degree is d

BisectionBW: The bandwidth betweentwo equal logical

subparts.

0-D 1-D 2-D 3-D 4-D5-D !


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SwitchingTopology Degree Diameter Ave Dist Bisection BW

1D Array 2 N-1 N / 3 1

1D Ring 2 N/2 N/4 2

2D Mesh 4 2 (N1/2 - 1) 2/3 N1/2 N1/2

2D Torus 4 N1/2 1/2 N1/2 2N1/2

k-ary n-cube 2n nk/2 nk/4 nk/4

Hypercube n =log N n n/2


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Network Topology - Real World


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SwitchingProblems

2d mapping of 3d topologies.

Internal speed of the switch is constant,

Bandwidth can be bottleneck


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Cluster vs. MultiprocessorsA Cluster is coordinated use of interconnected

computers in a machine room.

Challenges for Clustering

I/O Bus is slower and has more conflicts than

memory bus.

Administration problems Low memory usage efficiency

but memory cost is going down.


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Cluster vs. MultiprocessorsAdvantages

Fault Isolation , easy to replace failures

Scalability, expandability without stopping theapplication

Low cost, large scale multiprocessors cost more

Increasing communications bandwidth

Separate address space limits contamination error.

Hotmail, Google Inktomi, Aol, Amazon, Yahoousing clustered computers.


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Case Study - Google Stores and indexes Web combining more than

15 000 commodity-class PCs in 1 petabyte

(=1 000 000 GB) disk storage.

1 query =100 MB data+ 106 CPU cycle.

About 1000 query/s at peak time. Crawls web and updates indexes every 4 weeks

3 collocation sites ( 2 California + 1 Virginia)

Service time < 0.5 sec


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Case Study - Google Each site has 2488 Mbit/secconnection to Internet.

Sites linked to sister sites for

emergencies.

Each site has 2 switches of 128

1 Gbit/s Ethernet link. Switches are

connected to racks.

40 Racks at each site and each rack

has 80 PCs.

PC range from Celeron5300 to 1.4

GHz Intel Pentium III with 80 Gbyte

hard disk running Linux.


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Google- How It Works?1.Search QueryGoogle Cluster

GWS GWS GWS

GWS GWS

Google Web Server(GWS)

Index Servers Document Servers

2. 3. 5

Spell Checker

Ad Server

4


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Cluster Project at UCFParts

Ordered Costs

(135) AMD T-Bird 900MHz Processors $24,975.00

(135) ASUS -A7V Motherboards $20,925.00.

(15) Asante Interstack 8000 Switch, Hub, Card. $12,880.25

(15) Asante Interstack 8000 Switch, Hub, $12,778.00

(144) HD's, (5) RAID controllers $15,881.48

(128) ATI Rage Pro AGP video cards $4,480.00(150) Netgear 10/100 NICs $2,589.00

(135) PC133 DIMM 256MB $15,120.00

CasesSelection PendingMisc.(Racks,cables, UPS,etc.)$2,000.00


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References J. L. Hennessy and D. A.Patterson.Computer

Architecture: A Quantitative Approach. MorganKaufmann, San Mateo, CA, 2001.

J. F. Kurose and K.W. Ross,Computer Networks: ATop-Down Approach Featuring the Internet, 2ndedition. AddisonWesley, 2002.

A. DeCegama: Technology of Parallel Processing, 1989.

L.A.Barraso,

J.Dean and U

.Holzle

.Web Search ForA Planet: The Google Cluster Architecture. IEEE icro.

2003.

http://www.seecs.ucf.edu/cluster/index.html

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