Transcript Training - IIT Bombay

DISTRIBUTED
APPLICATIONS
Session 5 14:00 - 15:00
Dr Deepak B Phatak, IIT Bombay
SESSION OVERVIEW
Indian
Banking Scenario
Distributed Paradigms
How to Construct the
Distributed Infrastructure
Dr Phatak, IIT Bombay
Distributed Applications
2
BANKING BUSINESS
Primarily
Based On
– Interest Spread
– Fee Based Services
Multi
Location Operations
– Hierarchical Branch Network
Dr Phatak, IIT Bombay
Distributed Applications
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BANKING BUSINESS
Requires
Emphasis on
– Fast Movement of Funds
– Purposeful Expansion and
Retention of Customer Base
– Non Repudiation of Valid
Transactions. (TXNs)
Dr Phatak, IIT Bombay
Distributed Applications
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CONVENTIONAL RETAIL
BANKING
Low
Value High Volume TXNs
Attractive Deposit Products
Speedy Customer Service
Local TXNs, Within a Branch,
Remote TXNs, Within A City,
Anywhere Globally
Dr Phatak, IIT Bombay
Distributed Applications
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COMEERCIAL BANKING
Term
Loans
– Speedy Application Processing
– Avoiding NPAs
Fee
Based Services
– Fast Turn Around of TXN
– Special Services Needed
Dr Phatak, IIT Bombay
Distributed Applications
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HOUSE KEEPING
Management
Reporting
– Consolidation Reports
– Control Reports
– Performance Reports
– Statutory Reports
– Audit Reports
Dr Phatak, IIT Bombay
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INDIAN BANKING
SCENARIO
Traditionally
Branch Centric
GL is Accounting Backbone
S..S..Slow Fund Movement
Rudimentary Central Control
Focus On Customer Service ???
Dr Phatak, IIT Bombay
Distributed Applications
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INDIAN BANKING
SCENARIO
Use
Of Modern IT
– Started with Back Office
– TBM: Better Local Operations
– Useless Networks
– More Useless MIS, DSS
Dr Phatak, IIT Bombay
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INDIAN BANKING
SCENARIO
Coexistence
of Computerised,
Semi-Automated and Manual
Branch Operations
Stronger Networks Emerging
Any Banking Paradigm Must
– Work in Existing Situation
– Quickly Exploit Changes
Dr Phatak, IIT Bombay
Distributed Applications
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DISTRIBUTED PARADIGM
Emerged
Primarily
– To Provide Autonomous
Operations at Multiple Sites
– To Exploit Cheaper MIPS on
Smaller Machines
All
Real Life End to End
Computerisation is Distributed
Dr Phatak, IIT Bombay
Distributed Applications
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DISTRIBUTED PARADIGMS
Hierarchies
of Servers/Clients
Use of Message Queues and/Or
TP Monitors
Multiple Delivery Mechanisms
Dr Phatak, IIT Bombay
Distributed Applications
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METHODOLOGIES
Software
Engineering
Distributed Functionality Design
Network Design
Configuring an Application for
Growth
–
Change Management
Dr Phatak, IIT Bombay
Distributed Applications
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DELIVERY MECHANISMS
Post,
Telegrams, Fax
Machine Readable Data On Media
Data Transfer Through Networks
Dr Phatak, IIT Bombay
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EARLY NETWORKS
Arcnet
and Novell
Ethernet and Token ring
TCP/IP gets embedded into BSD
Unix
Dr Phatak, IIT Bombay
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MODERN NETWORKS
Ethernet
–
10 Mbps, 75% Market, Over 40
Million nodes
Token
Ring
– 4/16 Mbps, 16%
Fast
Ethernet
– 100 Mbps, 1%, growing fast
Dr Phatak, IIT Bombay
Distributed Applications
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MODERN NETWORKS
FDDI
–
100 Mbps, < 1%, Dying
ATM
–
25 Mbps to 2.4 Gbps, Nascent
Dr Phatak, IIT Bombay
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MODERN NETWORKS
(WAN BACKBONE)
North American
T1 or DS1 : 1.54 Mbps
– T3 or DS3 : 44.73 Mbps
European (and Indian)
– E1 : 2.04 Mbps (CCITT standard)
– E2 : 8.44 Mbps
– E3 : 34.36Mbps
–
Dr Phatak, IIT Bombay
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MODERN NETWORKS
(WAN BACKBONE)
Sonet
fibre Standards (ANSI,
Synchronous optical Network)
– OC1 to OC3
(51.84, 103.68, 155.52 Mbps)
– OC12 (622.08 Mbps)
– OC24 and OC48
(1.244 Gbps, 2.488 Gbps)
Dr Phatak, IIT Bombay
Distributed Applications
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MODERN NETWORKS
LAN-WAN-LAN
Interconnect
Various LAN Protocols
–
TCP/IP, IPX/SPX, SNA,
NETBEUI
Remote
–
access PC
SLIP, PPP.
Dr Phatak, IIT Bombay
Distributed Applications
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MODERN NETWORKS
LAN
to LAN
Bridge, Gateway
– IP Switching.
–
LAN
to WAN
Multi Protocol Routers.
– X.25 Switches, Gateway
–
Dr Phatak, IIT Bombay
Distributed Applications
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MODERN NETWORKS
WAN
Backbone
IP Over Leased Circuits / Dial up
Lines (Internet Is IP)
– X.25, Frame Relay, ATM (IP Can
Run Over These)
– VSATS ( Delays, 400 ms Per Hop)
–
Dr Phatak, IIT Bombay
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TRANSACTIONS
ACID
Properties Revisited
Atomicity: All or None
– Consistency : Stable & Correct
End State
– Isolation : Unaffected by Other
Happenings
– Durability : Persistent Effect
–
Dr Phatak, IIT Bombay
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TRANSACTIONS
A Single
User Example
Is It Simple to Handle?
– What Happens in a Crash?
–
Simple
If Things Work
Correctly
Difficult If Things Go Wrong.
Dr Phatak, IIT Bombay
Distributed Applications
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TRANSACTIONS
Concurrent
Distributed
Transactions, More Problems
Consistency and Isolation
– Roll Back Is Difficult
–
Lock
Step Synchronization
Through Two Phase Commit
Dr Phatak, IIT Bombay
Distributed Applications
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TRANSACTIONS
Flat
Transactions
Activities Are at Same Level
– SQL Implements Two Phase
Commit Protocol
– Backbone of Most (Leaf-level)
Applications
–
Dr Phatak, IIT Bombay
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FLAT TRANSACTIONS
Limitations
Complex Sub-activities With
Partial Roll Back?
– Human in the Loop Locks
Resources
– Temporally Long Transactions
– Bulk Update Transaction
–
Dr Phatak, IIT Bombay
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PAYMENT SETTLEMENT
A Complex Transaction
Jena of Jharsuguda gives a
cheque to Kantheeswaran at
Kandivali
– Kanthee Banks with Bank A at
Kandiwali: A(K)
– Jena With Bank B(J)
Dr Phatak, IIT Bombay
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PAYMENT SETTLEMENT
Kanthee
Presents Cheque to
A(K) and demands money
A(J) credits Kanthee’s account
AFTER collecting from B(J)
Dr Phatak, IIT Bombay
Distributed Applications
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DISTRIBUTED
PROCESSING SOLUTION
NCC
Distributed
Bank B
Jharsuguda
Transaction
Local Data Base
Local Data Base
Jena
Dr Phatak, IIT Bombay
Bank A
Kandiwali
Kantheeswaran
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PAYMENT SETTLEMENT
A presents
the instrument to
NCC
 NCC records information
Sorts all Instruments for Bank B
– Asks B to pay A
–
B
sends Cheque to Jharsuguda
(J)
Dr Phatak, IIT Bombay
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PAYMENT SETTLEMENT
B(J)
debits Jena
Informs NCC and A(K)
A(K) credits Kanthee
Multiple Service Branches Are
Actually Involved
Dr Phatak, IIT Bombay
Distributed Applications
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PAYMENT SETTLEMENT
Transaction
becomes funny if
Jena has no funds
– Cheque is lost in transit
– B Debits Jena But Sits Tight
– A Receives Info, But Does Not
Credit Kanthee
–
Dr Phatak, IIT Bombay
Distributed Applications
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PAYMENT SETTLEMENT
More
fun
NCC Asks B to Pay A
–
Later, B says give back my money
Jena
debited but Kanthee not
credited (Someone Using Float)
–
Kanthee sues A for delay
Dr Phatak, IIT Bombay
Distributed Applications
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DISTRIBUTED
PROCESSING SOLUTION
Inter Bank
Transaction Switch
NCC
Bank B
Jharsuguda
B
Switch
Distributed
Transaction
Local Data Base
Bank A
Kandiwali
Local Data Base
Jena
Dr Phatak, IIT Bombay
A
Switch
Kantheeswaran
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TRANSACTIONS
Emerging
Transaction
requirements
Distributed Transaction
– Multiple Processing Nodes
– Not All Nodes Computerised
– Not All Links Electronic
–
Dr Phatak, IIT Bombay
Distributed Applications
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TRANSACTIONS
ACID
properties difficult to
maintain for a Complex
Transaction
Human in the Loop is a MUST
– Carry Physical Instruments
– Multiple Data Capture
– Verify Signatures at B(J)
Dr Phatak, IIT Bombay
Distributed Applications
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TRANSACTIONS
A Possible
Solution is To Reduce
Humans in the Loop
Cheque Is a Message and Not a
Physical Instrument
– NCC Is a Swithing System and
Not a Physical Clearing House
– Electronic Transfer
–
Dr Phatak, IIT Bombay
Distributed Applications
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TRANSACTIONS
Multiple
Ways of Handling
– MICR processing
– Electronic Fund Transfer
– Debit and Credit Clearing
– Completely Automated Switch
Dr Phatak, IIT Bombay
Distributed Applications
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TRANSACTIONS
Emerging
Requirements
Multi Location Transactions
– Incorporation of Work Flow
– Internet Transactions
–
Dr Phatak, IIT Bombay
Distributed Applications
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MIDDLEWARE
A Vague
Term
All Distributed Software
Components That Support
Interactions Between
Application Software Executing
On Clients and Servers
Dr Phatak, IIT Bombay
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MIDDLEWARE
General
–
–
–
–
–
–
Communication stacks
Distributed Directories
Authentication Service
Remote Procedure calls
Queuing Services
Message Oriented Middleware (MOM)
Dr Phatak, IIT Bombay
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MIDDLEWARE
Service
–
–
–
–
–
–
Specific
Database related : ODBC, DRDA, CLI
OLTP Specific : ATMI ( Tuxedo)
Groupware Specific : MAPI, LN calls
Object Specific : CORBA, OLE
Internet Specific : HTTP, SSL
Management Specific : SNMP, ORBs
Dr Phatak, IIT Bombay
Distributed Applications
43
PEER TO PEER
COMMUNICATION
Connection
Oriented
– Synchronous
Connection
Less
– Asynchronous, Store and Forward
Dr Phatak, IIT Bombay
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EXAMPLES OF
DISTRIBUTED PARADIGM
Bank
Master and Branch Power
Bancs 2000
Micro Banker and Finware
Dr Phatak, IIT Bombay
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EXAMPLES OF
DISTRIBUTED PARADIGM
Provide
Branch Functionality
When Network Non Functional
Provide Complete Customer
Account and TXN Info
Attempt to Provide Retail and
Commercial Functionality
Dr Phatak, IIT Bombay
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EXAMPLES OF
DISTRIBUTED PARADIGM
SBI
IDBI
Bank
ICICI Bank
HDFC Bank
A Malysian Bank Uses Four
Servers For Many Branches
Dr Phatak, IIT Bombay
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DISTRIBUTED
INFRASTRUCTURE
Needs
Indian Messaging
Standards
Needs Proper Application
Software Development
Needs Work Flow Changes
Dr Phatak, IIT Bombay
Distributed Applications
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BUILDING BLOCKS
OS
Services
Task Preemption, Task Priority
– Semaphores, Inter process
communications
– Threads
–
Netware,
Dr Phatak, IIT Bombay
NT, OS2 Warp, UNIX
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BUILDING BLOCKS
OS
Services
Multi user high performance File
System
– Efficient Memory Management
– Dynamically linked run time
extensions
–
Dr Phatak, IIT Bombay
Distributed Applications
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BUILDING BLOCKS
More
–
–
–
–
–
O.S. Services
Ubiquitous Communications
Network operating System Extensions
Binary Large Objects (BLOBs)
Global Directories
Authentication and Authorization
Services
Dr Phatak, IIT Bombay
Distributed Applications
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BUILDING BLOCKS
More
O.S. Services
System Management
– Network time
– Database and Transaction
Services
– Internet Services
– Object-Oriented Services
–
Dr Phatak, IIT Bombay
Distributed Applications
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BUILDING BLOCKS
Server
Scalability
Symmetric Multiprocessor
Systems (SMP)
Massively Parallel Processors
based Servers (MPP)
Clusters
Dr Phatak, IIT Bombay
Distributed Applications
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BUILDING BLOCKS
Client
Systems
Non-GUI
–
–
ATMs, Barcode readers, cellular
phones, fax machines
Robots, Testers, Daemon Processes
GUI
–
Clients
Graphics, Menus, Windows, dialogues
Dr Phatak, IIT Bombay
Distributed Applications
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BUILDING BLOCKS
OOUI
Clients
Communicating objects
– Seamless access to information
and action
–
Compound
–
Documents
Live components
NextStep,
Dr Phatak, IIT Bombay
Mac OS
Distributed Applications
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BUILDING BLOCKS
SHIPPABLE
–
–
–
–
PLACES
Place: A visual ensemble of related
components
Shippable Place: A mobile container
can interact with collaborative
environments
Web, web form, Java enabled web
pages, Compound Docs
Dr Phatak, IIT Bombay
Distributed Applications
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NETWORK OPERATING
SYSTEMS
Provide
transparency in
Location, Namespace, logon
– replication, access, time, failure
–
Distributed
Security (C2)
Authentication, Authorisation
– Audit trails
–
Dr Phatak, IIT Bombay
Distributed Applications
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MORE ON SECURITY
Kerberos
from Athena (MIT)
Encryption, Session Key
Data Encryption Standard
(DES-3)
–
Shared Private key
RSA,
–
DH Algorithms
Public/Private key
Dr Phatak, IIT Bombay
Distributed Applications
58
PEER TO PEER
COMMUNICATION
Sockets
BSD 4.2 UNIX, 1981
– Netid.Hostid.Portid (IP + Port)
– Port (16 bit): entry point to service
–
Transport
–
Layer Interface (TLI)
AT&T, 1986
Dr Phatak, IIT Bombay
Distributed Applications
59
PEER TO PEER
COMMUNICATION
Connection
Oriented
Session based
– Virtual Circuits
–
Connectionless
–
Datagrams
Dr Phatak, IIT Bombay
Distributed Applications
60
PEER TO PEER
COMMUNICATION
Internet
Package Exchange IPX
Based on Xerox Network Services
(XNS)
– Sequential Packet Exchange (SPX)
–
NetBIOS,
–
NetBEUI
IBM, Sytec (1984), Microsoft
Dr Phatak, IIT Bombay
Distributed Applications
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PEER TO PEER
COMMUNICATION
Named
Pipes
 Remote Procedure Calls
Locate and start Server functions
– Define and pass parameters
– Handle Security and Failures
– Data representation
–
Dr Phatak, IIT Bombay
Distributed Applications
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PEER TO PEER
COMMUNICATION
Message
Oriented Middleware
(MOM)
–
–
–
–
–
Distributed Application Development
(DAD) needs MOM
MOM consortium in 1993
Queued Vs Call-return of RPC
Provides Asynchronous Mechanism
Ideal for Objets
Dr Phatak, IIT Bombay
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