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ENTERPRISE COMPUTING
UNIT- III
UNIT III - SERVICES FOR DISTRIBUTED ENTERPRISE SYSTEMS
TWO MARKS
1. Specify the use of naming service.
An object is a Java object class that is stored on the memory. The name of an
object is a string of character that is associated with the location of the object and name is
the key used to retrieve the object.
A naming service is used to relate an Object name to an object location and
enable a program to access the object by referring the object name.
(eg.,) Domain Name System, File system
2. Specify the use of JNDI in naming system
The Java Naming and Directory Interface (JNDI) provides a standard Java
interface-to naming system that can be used with various types of underlying naming
systems. JNDI can also be used to name and reference objects that lie outside of a
particular naming system. Furthermore, JNDI also provides interfaces for encapsulating
and handling events that can be generated from a naming service
3. What are the various packages present in JNDI
The JNDI class libraries are partitioned into the following packages:
 javax.naming
 javax.naming.directory
 javax.naming.event
 javax.naming.ldap
 javax.naming.spi
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UNIT- III
4. Define the term CORBA Naming
The OMG’s CORBA Naming Service (also called Object Naming Service and
CosNaming) presents the primary and standard way for mapping between names and
object in CORBA ORB.
5. Define the Naming Context in CORBA
Naming contexts in CORBA contain a list of names that are all unique to that
context in which each binding has a binding type indicating whether the name is bound to
either a CORBA object or another naming context. Even though a logical name can be
bound to a naming context, naming contexts do not need to be associated with logical
names.
6. What are the operations done using naming context.
Operations on naming contexts include binding and rebinding names to
objects,resolving objects given a name, unbinding objects, creating subcontexts, and
listing names associated with the context.
7. What is the need of DNS
The DNS is used on Internet / Intranet to relate domain name with IP address.
(for example, www.yahoo.com) to and from IP addresses (for example, 204.71.200.68).
DNS names have a syntax convention and map to IP addresses that are logical addresses
of network devices or hosts.
8. What are the various JNDI directory services available?
JNDI Directory Services
 NIS (Network Information System) as a Directory Service
 NDS (Novell Directory Service) as a Directory Service
 LDAP (Lightweight Directory Access Protocol) as a Directory Service
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ENTERPRISE COMPUTING
UNIT- III
 CORBA as a Trading Service
 Jini as a Trading Service
 Microsoft Active Directory Services
9. Which service are mainly used in enterprise network resource
 The Novell Directory Service (NDS) is a popular directory service for
managing enterprise network resources and network user information.
 NDS's multiplatform support and its easy-to use GUI administration
toolkit have made it fairly popular with network administrators.
 NDS servers allow NDS clients to obtain access to such resources as
networks, file servers, print servers, and database servers from a centrally
managed location.
 Using NDS, administrators can enable access, limit access, and disable
access to such resources by users in an easily configurable fashion.
10. What are the basic functionalities present in LDAP?
The LDAP API supports most of the basic directory service functionality, include
 Bind (connect/authenticate) to an LDAP directory server.
 Unbind (disconnect) from an LDAP directory server session.
 Add a new directory object entry.
 Delete a directory object entry.
 Modify a directory object entry.
 Rename a directory object entry.
 Search for directory object entries.
 Compare an entry with particular attribute values to determine whether it
contains those values
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UNIT- III
11. Define Jini Services in Trading Services
 Jini is a collection of Java APIs and components for building
distributed systems.
 Jini is a lightweight layer of Java code that rests atop the Java 2 platform.
 Jini can run on top of the J2SE and J2EE, as well as the J2ME.
 Jini depends on Java's Remote Method Invocation (RMI) distributed
communications infrastructure.
 Jini and RMI together offer a set of APIs and infrastructure for building
distributed services.
12. What are the packages used in Jini?
 JSK (The Jini Software Kit)
 JXP (The Java eXtended Platform)
 JCP (The Jini Core Platform)
13. What are the basic steps to create Jini Services?
 Define Jini Service Interface
 Implement Jini Service Proxy
 Implement Remote Process Interface
 Implement the Jini Service Registrar
14. Define Activation Services.
An activation service is a component of software, responsible for bringing other
software from an inactive state into an active in-memory state.
(e.g.,) 1. Java class file become active when it is instantiated as an object.
2. Entire program become active when it generate its own process.
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ENTERPRISE COMPUTING
UNIT- III
15. Diagrammatically represents the Activation service available
16. What are the sequences of process occurs during client request in RMI
activation framework?
1. RMI client attempts reference
2. Remote reference faults to activator reference
3. Activator looks up activation info
4. Activator accesses/spawns JVM process
5. Activator requests activated object
6. JVM process loads activatable class
7. JVM process instantiates activatable object
8. Activated remote reference is returned
9. RMI client has remote reference
17. What are the sequences of process occurs during client request in CORBA
activation framework?
1. CORBA client attempts reference
2. ORB obtains POA reference
3. POA obtains object ID
4. POA looks for cached object instance
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UNIT- III
5. POA requests servant from servant manager
6. Servant manager loads servant information
7. Servant manager instantiates servant
8. POA obtains servant handle
9. POA invokes servant
10. CORBA client request satisfied
18. What are the compound Life Cycle interfaces available
The compound life cycle service uses the same notation to enables copies, moves,
creations and deletions.
These are the key Compound Life Cycle interfaces:
 Operations Factory
 Operations
 Node
 Relationship
 Role
19. Define Messaging Service in distributed application
Messaging Service is a software that provides support for passing messages
between distributed applications in a reliable, asynchronous, loosely coupled, languageindependent, platform independent and often configurable fashion.
A messaging service also provides an interface for messaging clients
20. What the two types of Message Service Implementations?
1. Using Messaging middleware software
2. Using software embedded into client (Thick Client Software)
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ENTERPRISE COMPUTING
UNIT- III
Messaging middleware
Messaging thick client software
21. What are the various types of Messaging Services?
 Point-to-Point Messaging
 Publish-Subscribe Messaging
 Push and Pull Messaging Models
 Message Filtering, Synchronicity, and Quality
 Email Messaging
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UNIT- III
22. Define Message Oriented Middleware (MOM).
MOM API defines how distributed applications should utilize an underlying
MOM message channel or queue for communicating messages to one another. Messages
are passed between applications via MOM in a way that does not block the sender of that
message. That is, the sender can send a message and allow the MOM to ensure that it gets
to the intended receiver without waiting for a response from the receiver.
23. Define Java Message Service.
Java Message Service (JMS) is a Java API that defines how messaging clients can
interface with underlying messaging service. JMS also provides an interface that
underlying messaging service providers implement to provide JMS services to clients.
24. What is the use of CORBA Event Service?
The CORBA Event Service is a CORBA service that provides basic messaging
facilities via encapsulation of events that can be generated by objects and delivered to
other objects. The CORBA Event Service handles the mechanisms for delivering the
event from an event supplier object to an event consumer object after the event has been
generated.
25. What are the present for event communication?
Two models for event communication via the event channel are the "push model" and
the "pull model." The push model of events is used when a supplier pushes an event to
the event channel object, which is then passed onto the consumer by the event channel.
The pull model of events is used when a consumer attempts to pull an event from the
event channel object, which pulls events from suppliers.
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26. What are the various Email messages present?
 JavaMail Generic Messages
 JavaMail Multipart Messages
 JavaMail MIME Messages
27. What are the various event/listener combinations present in Java mail?
The various event/listener combinations defined for JavaMail events are shown
 Connection Event Model: Manages mail session connection opening,
closing, and disconnect events.
 Folder Event Model: Manages mail folder creation, deletion ,and
renaming events.
 Store Event Model: Manages mail message notification events.
 Transport Event Model: Manages mail communication delivery,
non delivery, and partial-delivery events.
 Message Count Event Model: Manages message folder addition and
deletion events.
 Message Changed Event Model: Manages message content change
events.
28. Define Transaction Services for the middleware
Transaction services are middleware services that facilitate the provision of
transaction semantics and ACID principle behavior for your enterprise applications.
Transaction services provide an API for programmers to use that enables them to
encapsulate which operations should be contained within a transaction.
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ENTERPRISE COMPUTING
UNIT- III
29. What are the steps involved in Two Phase Commit Protocol?
These are the two-phase commit protocol steps:
 Phase One—Commit Preparation: A prepare for commit message is first sent
to each resource manager with updated data involved in a transaction. Each
resource manager then persists a description of the updates it has made within the
context of the current transaction. Resource managers can also opt to abort the
transaction at this stage, and then the whole transaction can be aborted by the
transaction manager.
 Phase Two—Actual Commit: If the transaction was not aborted, the transaction
manager will send a commit message to all resource managers involved in the
transaction. The resource managers will then commit their updates.
30. Define Object Transaction Service (OTS).
CORBA Service is known as OTS, which defines the interface to implement
transaction for distributed CORBA objects. Distributed CORBA objects participate in the
transaction via ORB (Object Request Brokerage).
31. What is meant by the term assurance in an enterprise?
Providing assurance for an enterprise means providing secure, reliable, available,
maintainable and perhaps safe solutions.
32. List the general assurance process.
 Identify assurance problem
 Assess risk
 Generate risk reduction plan
 Assess residual risk
 Assess cost of risk reduction plan
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UNIT- III
General Assurance process
33. Draw the basic security model.
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34. Define the term Cryptography.
Cryptography is the science of information security. The word is derived from the
Greek kryptos, meaning hidden. Cryptography is closely related to the disciplines of
cryptology and cryptanalysis. Cryptography includes techniques such as microdots,
merging words with images, and other ways to hide information in storage or transit.
However, in today's computer-centric world, cryptography is most often associated with
scrambling plaintext (ordinary text, sometimes referred to as cleartext) into cipher text (a
process called encryption), then back again (known as decryption). Individuals who
practice this field are known as cryptographers.
Modern cryptography concerns itself with the following four objectives:




Confidentiality
Integrity
Non-repudiation
Authentication
35. What are the various classes of Cryptography?
 Message Digest Cryptography (Algorithms: MD2, MD4, MD5,
SHA, SHA-I, MAC)
 Symmetric Key Cryptography (Algorithms: DES, Triple DES,
RC2, RC4,RC5)
 Asymmetric Key Cryptography (Algorithms: DSA, RSA, Diffie
Hellman)
36. List the various types of Authentication.
 Password-based identity and authentication
 Physical token–based identity and authentication
 Biometrics-based identity and authentication
 Certificate-based identity and authentication
37. What are the various Access Control available to provide assurance?
 Discretionary Access Control
 Role-Based Access Control
 Mandatory Access Control
 Firewall Access Control
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