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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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Network Topology- Centralized
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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Network Topology- Centralized
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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Network Topology- Distributed
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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Network Topology- Distributed
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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Network Topology- Distributed
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