Session5

canoeornithologistΔίκτυα και Επικοινωνίες

26 Οκτ 2013 (πριν από 4 χρόνια και 2 μήνες)

71 εμφανίσεις

DISTRIBUTED
APPLICATIONS




Session 5 14:00
-

15:00


Dr Deepak B Phatak, IIT Bombay


Dr Phatak, IIT Bombay

Distributed Applications

2

SESSION OVERVIEW


Indian Banking Scenario


Distributed Paradigms


How to Construct the
Distributed Infrastructure

Dr Phatak, IIT Bombay

Distributed Applications

3

BANKING BUSINESS


Primarily Based On


Interest Spread


Fee Based Services


Multi Location Operations



Hierarchical Branch Network

Dr Phatak, IIT Bombay

Distributed Applications

4

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

5

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

6

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

7

HOUSE KEEPING


Management Reporting


Consolidation Reports


Control Reports


Performance Reports


Statutory Reports


Audit Reports

Dr Phatak, IIT Bombay

Distributed Applications

8

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

9

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

Distributed Applications

10

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

11

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

12

DISTRIBUTED PARADIGMS


Hierarchies of Servers/Clients


Use of Message Queues and/Or
TP Monitors


Multiple Delivery Mechanisms

Dr Phatak, IIT Bombay

Distributed Applications

13







METHODOLOGIES


Software Engineering


Distributed Functionality Design


Network Design


Configuring an Application for
Growth


Change Management

Dr Phatak, IIT Bombay

Distributed Applications

14







DELIVERY MECHANISMS


Post, Telegrams, Fax


Machine Readable Data On Media


Data Transfer Through Networks

Dr Phatak, IIT Bombay

Distributed Applications

15







EARLY NETWORKS


Arcnet and Novell


Ethernet and Token ring


TCP/IP gets embedded into BSD
Unix

Dr Phatak, IIT Bombay

Distributed Applications

16







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

17







MODERN NETWORKS


FDDI


100 Mbps, < 1%, Dying


ATM


25 Mbps to 2.4 Gbps, Nascent

Dr Phatak, IIT Bombay

Distributed Applications

18







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

Distributed Applications

19







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

20







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

21







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

22







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

Distributed Applications

23







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

Distributed Applications

24







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

25







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

26





TRANSACTIONS


Flat Transactions


Activities Are at Same Level


SQL Implements Two Phase
Commit Protocol


Backbone of Most (Leaf
-
level)
Applications

Dr Phatak, IIT Bombay

Distributed Applications

27







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

Distributed Applications

28

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

Distributed Applications

29

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

30

DISTRIBUTED
PROCESSING SOLUTION

Local Data Base

Local Data Base

Bank B

Bank A

NCC

Kantheeswaran

Kandiwali

Jharsuguda

Jena

Distributed

Transaction

Dr Phatak, IIT Bombay

Distributed Applications

31

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

Distributed Applications

32

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

33


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

34

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

35

DISTRIBUTED
PROCESSING SOLUTION

Local Data Base

Local Data Base

Bank B

Bank A

NCC

Kantheeswaran

Kandiwali

Jharsuguda

Jena


Inter Bank

Transaction Switch

Distributed

Transaction

B

Switch

A

Switch

Dr Phatak, IIT Bombay

Distributed Applications

36







TRANSACTIONS


Emerging Transaction
requirements


Distributed Transaction


Multiple Processing Nodes


Not All Nodes Computerised


Not All Links Electronic

Dr Phatak, IIT Bombay

Distributed Applications

37







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

38







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

39

TRANSACTIONS


Multiple Ways of Handling


MICR processing


Electronic Fund Transfer


Debit and Credit Clearing


Completely Automated Switch

Dr Phatak, IIT Bombay

Distributed Applications

40







TRANSACTIONS


Emerging Requirements


Multi Location Transactions


Incorporation of Work Flow


Internet Transactions

Dr Phatak, IIT Bombay

Distributed Applications

41







MIDDLEWARE


A Vague Term


All Distributed Software
Components That Support
Interactions Between
Application Software Executing
On Clients and Servers

Dr Phatak, IIT Bombay

Distributed Applications

42







MIDDLEWARE


General


Communication stacks


Distributed Directories


Authentication Service


Remote Procedure calls


Queuing Services


Message Oriented Middleware (MOM)

Dr Phatak, IIT Bombay

Distributed Applications

43







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

44

PEER TO PEER
COMMUNICATION


Connection Oriented


Synchronous


Connection Less


Asynchronous, Store and Forward

Dr Phatak, IIT Bombay

Distributed Applications

45

EXAMPLES OF
DISTRIBUTED PARADIGM


Bank Master and Branch Power


Bancs 2000


Micro Banker and Finware

Dr Phatak, IIT Bombay

Distributed Applications

46


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

Distributed Applications

47

EXAMPLES OF
DISTRIBUTED PARADIGM


SBI


IDBI Bank


ICICI Bank


HDFC Bank


A Malysian Bank Uses Four
Servers For Many Branches

Dr Phatak, IIT Bombay

Distributed Applications

48

DISTRIBUTED
INFRASTRUCTURE


Needs Indian Messaging
Standards


Needs Proper Application
Software Development


Needs Work Flow Changes

Dr Phatak, IIT Bombay

Distributed Applications

49








BUILDING BLOCKS


OS Services


Task Preemption, Task Priority


Semaphores, Inter process
communications


Threads


Netware, NT, OS2 Warp, UNIX

Dr Phatak, IIT Bombay

Distributed Applications

50








BUILDING BLOCKS


OS Services


Multi user high performance File
System


Efficient Memory Management


Dynamically linked run time
extensions

Dr Phatak, IIT Bombay

Distributed Applications

51







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

52







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

53







BUILDING BLOCKS


Server Scalability


Symmetric Multiprocessor
Systems (SMP)


Massively Parallel Processors
based Servers (MPP)


Clusters

Dr Phatak, IIT Bombay

Distributed Applications

54







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

55







BUILDING BLOCKS


OOUI Clients


Communicating objects


Seamless access to information
and action


Compound Documents


Live components


NextStep, Mac OS

Dr Phatak, IIT Bombay

Distributed Applications

56

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

57

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

58

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

59

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

60

PEER TO PEER
COMMUNICATION


Connection Oriented


Session based


Virtual Circuits


Connectionless


Datagrams

Dr Phatak, IIT Bombay

Distributed Applications

61

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

62

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

63

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