D ISTRIBUTED S YSTEMS – A RCHITECTURE M ODELS Janani C Krishnamani CSC 8320 Fall 2011.
-
Upload
keagan-tomson -
Category
Documents
-
view
221 -
download
4
Transcript of D ISTRIBUTED S YSTEMS – A RCHITECTURE M ODELS Janani C Krishnamani CSC 8320 Fall 2011.
DISTRIBUTED SYSTEMS – ARCHITECTURE MODELS
Janani C Krishnamani
CSC 8320
Fall 2011
OUTLINE
Introduction Architecture models
System architectures Communication Network architectures
Examples Future Ideas
INTRODUCTION
WHAT ARE DISTRIBUTED SYSTEMS?
Collection of independent computers that appear to the user as one single entity
Examples Systems in a LAN, WAN, MAN World Wide Web Torrent networks Clusters Cloud servers
WHY INTERCONNECT SYSTEMS? [1]
To pass a message from one system to another
Share common resources Beneficial to use multiple low end processors
than one high end processor Fault tolerance through redundancy
CLASSIFICATION
CLASSIFICATION [2]
Based on system architecture Client – Server model Peer – Peer model
Based on communication network Bus Switched
Based on level of coupling Tightly coupled (parallel) Loosely coupled (distributed)
BASED ON SYSTEM ARCHITECTURE : CLIENT SERVER MODEL
One server acts as the principal control agent Several nodes report to the server Advantages:
Better control and security Concentration of functions in high performance
servers Disadvantages:
Not robust due to lack of redundancy Performance suffers if the number of clients
increases Examples:
Workstation – Server Model Processor Pool Model
BASED ON SYSTEM ARCHITECTURE : WORKSTATION – SERVER MODEL
Many workstations connect to the network. Workstations provide local processing and an
interface to the network. Consist of one or more client workstations
connected to one or more server workstations using a communication network.
Mainly used for resource sharing
BASED ON SYSTEM ARCHITECTURE : PROCESSOR POOL MODEL
All the processing is moved to a pool of processors
No concept of a home machine Workstations are dummy terminals with good
graphical display Terminals have minimum intelligence like
remote booting, remote mounting of file systems, virtual terminal handling and packet assembly and disassembly services
BASED ON SYSTEM ARCHITECTURE : PEER – PEER MODEL
All the nodes in the network have equal privilege
No special routing server required. The nodes themselves take care of routing the data
Peers – both suppliers and consumers As the number of nodes increases, the
bandwidth increases Reduces single point failures It is less secure Usually used for sharing of resources – files,
audio - visual media
BASED ON COMMUNICATION NETWORK : BUS – BASED INTERCONNECTION
Usually used in Point – Point connection systems
System connected by computer bus The access to communication media is time
shared IEEE 802 LAN Standard
Ethernet, Token Bus, Token Ring, Fiber Distributed data Interface (FDDI), Fiber Queue Dual Buses (FQDB)
BASED ON COMMUNICATION NETWORK : SWITCH – BASED INTERCONNECTION
Usually used in multi point connection systems
Systems connected by network switches The access to communication media is both
time and space shared – but cost equally higher than bus
Private switches – Crossbar, multistage switch
Public switch systems – Integrated Services Digital Network (ISDN), Asynchronous Transfer Mode (ATM
Switches in public networks also perform routing
BASED ON LEVEL OF COUPLING : LOOSELY COUPLED SYSTEMS
Each processor has its own memory Runs its own OS Do not communicate frequently Can be placed in geographically separate
regions Also called distributed computing
BASED ON LEVEL OF COUPLING : TIGHTLY COUPLED SYSTEMS
Processors share a common memory Run on a single OS Communicate very frequently Usually connected through high speed
connection methods Also called parallel computing
LEVEL OF COUPLING
Microprocessors Clusters LAN Global Internet
SmallFast
LargeSlow
More Tightly Coupled More Loosely Coupled
Closer in physical proximity Farther in physical proximity
GRID COMPUTING [3]
Complete nodes connected by a conventional network interface like Ethernet.
Not tightly coupled. Can be geographically diverse.
The communication is not high speed - works fine in environments that require less communication.
A single task is adequately parallelized and each part is given to a different node that computes it independently - so no concurrency issues involved.
CLOUD COMPUTING
WHAT IS CLOUD COMPUTING [4]
Parallel and distributed system consisting of a collection of inter-connected and virtualized computers
Presented to the user as a single computer Services provided:
Software as service Platform as service Infrastructure as service
Advantages Speed of Operation Power saving Abstraction Virtualization
EXAMPLES
FOLDING@HOME [6]
Grid computing project designed to perform computationally intensive simulations of protein folding and other molecular dynamics
The most powerful distributed computing cluster in the world – Guinness 2007
Primary contributors – thousands of everyday personal computers
Processes run in the background utilizing cpu idle time
In late March 2011 Folding@home briefly peaked above the 7 native petaFLOP barrier.
WINDOWS AZURE PLATFORM [7]
On demand platform used to build, host and scale web applications through windows datacenter.
Platform as a service Build, host and maintain web applications
running on Microsoft Datacenter OS – Windows Azure Services
Live Services SQL Azure AppFabric SharePoint Services Dynamic CRM Services
FUTURE…
FUTURE OF DISTRIBUTED COMPUTING…
An expanded peer - peer network with every personal computer interconnected with every other.
Utilization of CPU cycles and hard disks during idle time
Improvements in security and performance that void the need for a centralized control server and a data center
REFERENCES
[1] http://en.wikipedia.org/wiki/Distributed_computing#Architectures
[2] http://en.wikipedia.org/wiki/Grid_computing [3] http://en.wikipedia.org/wiki/Cloud_computing [4] Ghosh, Anup; Arce, Ivan; , "Guest Editors'
Introduction: In Cloud Computing We Trust - But Should We?," Security & Privacy, IEEE , vol.8, no.6, pp.14-16, Nov.-Dec. 2010doi: 10.1109/MSP.2010.177
[5] http://en.wikipedia.org/wiki/Folding@Home [6] http://en.wikipedia.org/wiki/Blue_Gene/ [7] http://en.wikipedia.org/wiki/Windows_Azure
THANK YOU!