ITIL interview questions-1

ITIL interview questions

• what is outsourcing?

If we used an external organisation to help us develop part of our service it's called outsourcing

• What is an OLA?

The Operational Level Agreement is an agreement between an IT service provider and another part of the same organization. This could be the development team, the support team or helpdesk

• What are the steps you would follow when a Change Request comes in?

� Record it
� Evaluate it
� Prioritize it
� Plan it
� Test it
� Finally, implement it

http://www.dumpsquestions.com/forums/viewquestion.php?question=1487&..

• What is SLA?

A: A service level agreement or SLA is the contract between an organization and its customers. Customers can be external or internal and SLA tells the user what to expect in regards to response time and uptime of any IT technology.

What is change management?
Change management is a group of people who identify and approve changes to the system. Change management helps all parties involved to review the changes that will take place and approve them to ensure that changes to not have a severe negative impact on the system.

What does an SLA contain?
The SLA contains the amount of time a response is made when issues occur, the responsibility of each organization, target numbers and uptime percentages, the times at which support is available, and any change history or technical standards provided by the organization.

What is a service design package?
he SDP contains any major change requirements for new IT service and information when retiring any hardware or software.
http://resources.infosecinstitute.com/itil-interview-questions/

• Difference between  ITIL v3 and v2. 

Managing services as a portfolio is a new concept in ITIL V3
Service Catalogue Management was added as a new process in ITIL V3

ITIL based models adopted by organization .
Microsoft MOF
Hewlett - Packard ( HP ITSM Reference Model)
IBM ( IT Process Model )

Define Service strategy?
How to design, develop and implement service management for organization is define under service strategy.
Ø  What are we going to provide?
Ø  Can we afford it?
Ø  Can we provide enough of it?
Ø  How do we gain competitive advantage?


Define Service Design?
How to design develop services and service management and converting service objective in to range of services.
Ø  How are we going to provide it?
Ø  How are we going to build it?
Ø  How are we going to test it?
Ø  How are we going to deploy it?

Define Service transition.
How to implement services in production as per design services.
Ø  Coordination and managing of the process
Ø  Build, test and deploy a release in to production.


Define Service operations
How to manage service on an ongoing basis to ensure their objectives are achieved.
Service operation is responsible for all ongoing activates required to support and deliver services

http://itilinterviewquestions.blogspot.com.tr/2013/06/itil-interview-part-1.html

• ITIL Interview Questions and Answers

1. What is ITIL?
2. What are types of service provider?
3. Explain Service knowledge management system?
4. Explain Strategic/Tactical/Operational level changes?
5. Explain Change Management?
6. Service Transition?
7. Explain the availability Managements?
8. What is Service level Management?
9. Types of service catalogue?
10.Explain Service Design?
11. Return on Investment?
12. Explain Retired services?
13. Explain Service portfolio, Service catalogue and service pipeline?
14. Explain Service strategy process?
15. What is Service process management Process?
16. Define Service Management?
17. What is continues service improvement (CSI)?
18. Define Service operations?
19. Define Service transition?
20.Define Service Design?
21. Define Service strategy?
22.Explain ITIL service Life cycle model?
23.What is ITIL service management?
24.What are the ITIL based models adopted by organization?

http://tekslate.com/itil-interview-questions-and-answers

• ITIL - Interview Questions

Q3. Can you name 3 types of SLA?

http://www.accelerated-ideas.com/free-itil-training/itil-interview-questions-11995.aspx

• Explain a Known Error

A Known Error refers to an identified problem that has an acknowledged root cause and a solution.
It consists of the following:
Status
Error Description
Root Cause
Workaround

What is Configuration Management’s purpose in ITIL?
Its main purpose is to receive, collect, store, manage and verify data on IT assets and configurations.

What is the difference between a project and a process?
A project usually has a fixed time span whereas a process is continuous and does not have an end date.

What are the responsibilities of an ITIL Service Desk?
Responsibilities of an ITIL Service Desk are:
To log, classify and prioritize incidents
To investigate the incidents
Resolving the incident
Incident management reporting

Differentiate between proactive and reactive problem management.
proactive problem management prevents incidents from occurring by identifying potential problems and errors in the IT infrastructure
reactive problem management recognizes and eliminates the root cause of incidents that are witnessed.

Differentiate between an incident and a problem.
An incident is referred to an event that leads to disturbances and disruptions in an IT service, and a problem is the underlying cause of these incidents.

What is Post Implementation Review (PIR)?
It is usually performed after the change request is put into effect to determine if the change and its implementation were successful.

Define Operational Level Agreement (OLA)
Operational Level Agreement (OLA) is a contract which emphasizes the different IT groups in a company and how they design their services to support SLAs.

What is the difference between customers and end-users?
A customer is an entity who has the ability to choose from various products or suppliers
an end-user is the direct recipient of a product or service.

Differentiate between Service Request and an Incident
Service Requests are formal requests that are processed by a user for a service of information
Incident is an unplanned interruption to an IT service or reduction in the quality of an IT service.

Explain Service Portfolio, Service Catalog and Service pipeline
Service Portfolio is a comprehensive list consisting of all the services that are provided by a service provider to the customers.
Service Catalog is a subset of Service Portfolio which includes a list of the services that are ready to be offered to the customers.
Service Pipeline refers to services that are under development process.

Differentiate between Emergency Changes and Urgent Changes.
Emergency Changes are the highest priority changes which require fast implementation
Urgent Changes are changes that serve an important business or legal requirement but do not help to restore a service.

What is a Change Advisory Board (CAB)?
Change Advisory Board refers to a group of authoritative people who aid in carrying out the change management process with the authorization, assessment, prioritization, and scheduling of the requested changes.

What is a Freeze period in ITIL®?
a particular time period in the development procedure after which strictness and severity is observed in the rules required for making changes to the source code.

What are the ITIL models adopted by an organization?
Microsoft MOF (Microsoft Operations Framework)
Hewlett Packard (HP ITSM Reference Model)
IBM (IT Process Model)


Name the 4 P’s required for effective Service Management in ITIL
People
Processes
Products
Partners

Who protects and maintains the Known Error database?
The Problem Manager is responsible to maintain and protect the Known Error database as well as facilitates the initiation of the formal closure of all Problem records.

Define Workaround.
When the root cause of an issue or problem has not been resolved, a workaround acts as a temporary method for resolving the issue.

What is the RACI model?
• Responsible – Responsibility assigned to a particular person the complete the task.
• Accountable – Person held accountable for the given task.
• Consulted – People or groups who are consulted for the task.
• Informed – People who are kept informed about the progress of the on-going task

What is Configuration baseline?
a baseline that is used for a configuration only and has been formally agreed on and managed by the change management process.

What is Service Strategy?
Service Strategy is a set of policies and objectives that are established to achieve a service goal.

Name the four P’s of Service Strategy.
Perspective – the vision behind the strategy and its course
Pattern – method taken to implement the strategy
Position – basis on which the strategy will be completed
Plan – ways to achieve the goal

What do you understand by Service Transition?
The objective of this stage is to build and deploy IT services for different organizations.
This stage also responsible for ensuring that changes to services and service management processes are performed in a coordinated way.
It consists of the following processes:
Change Management
Change Evaluation
Project Management
Application Development
Release and Deployment Management
Service Validation and Testing
Service Asset and Configuration Management
Knowledge Management

List down the four layers of service management measurements.
Progress: This is responsible for handling the progression of the current service operations
Compliance: This mainly deals with the compliance of the trending industry process and market standards
Effectiveness: This helps in maintaining the effectiveness of the services
Efficiency: This helps with the efficiency of service maintenance and workflow

The difference between effectiveness and efficiency can be summed up shortly, – Being effective is about doing the right things, while being efficient is about doing things right.

What are the various types of Service Providers in ITIL processes?
Internal Service Provider: This type of provider deal with internal organization management.
External Service Provider:This type of provider generally deal with external organization management
Share Services: his type of provider usually has its autonomous presence inside the organization.

Explain the plan-do-check-act (PDCA) cycle?
Plan: Identifying and planning the improvements
Do: Implementation of improvements
Check: Monitoring, Measuring and Reviewing
Act: Improvements are completely implemented

https://www.edureka.co/blog/interview-questions/itil-interview-questions/

What is the difference between RMI & Corba?

What is the difference between RMI & Corba?

CORBA was made specifically for interoperability across programming languages
programs can be built to interact in multiple languages
The server could be written in C++, the business logic in Python, and the front-end written in COBOL in theory
In a multi-language CORBA environment, dynamic class loading is not possible


RMI is a total Java solution, the interfaces, the implementations and the clients, all are written in Java.
RMI allows dynamic loading of classes at runtime
The important advantage to dynamic class loading is that it allows arguments to be passed in remote invocations that are subtypes of the declared types

http://www.javabeat.net/articles/113-rmi-interview-questions-1.html

How does email work?

Lisa opens her email program (Outlook Express), uses her email account, lisa@otherisp.com, and writes an email message to bob@comentum.com.

Her Outlook Express sends the message through TCP port 25 of Lisa's Internet connection, then to the other ISP's SMTP server (still on TCP port 25).

The other ISP's SMTP server finds the destination's SMTP server (in this case, Comentum) and sends the message out to Comentum's SMTP server (through TCP port 25 of her Internet connection).

Comentum's SMTP server sends the message to Comentum's POP3 server where the message waits for Bob to pick it up.

Bob opens his email program (Outlook Express) and when he clicks Send/Recv button, his Outlook Express sends a request through Bob's Internet connection to Comentum's POP3 server (through TCP port 110) and downloads Bob's message to Bob's computer where he sees Lisa's message.

• IMAP

For example, the client will download all the messages and store their complete contents on the local machine (just like it would if it were talking to a POP3 server). The messages still exist on the IMAP server, but you now have copies on your machine. This allows you to read and reply to e-mail even if you have no connection to the Internet. The next time you establish a connection, you download all the new messages you received while disconnected and send all the mail that you wrote while disconnected.


References:
http://www.comentum.com/how-email-works.html
http://computer.howstuffworks.com/e-mail-messaging/email5.htm

TCP vs UDP

• Transmission Control Protocol (TCP)

TCP is connection-oriented protocol
When a file or message send it will get delivered unless connections fails
You don't have to worry about data arriving in the wrong order.
(TCP) protocol provides extensive error checking mechanisms such as flow control and acknowledgment of data.

Examples:
World Wide Web (TCP port 80)
e-mail (SMTP TCP port 25 Postfix MTA)
File Transfer Protocol (FTP port 21)
Secure Shell (OpenSSH port 22)

• User Datagram Protocol (UDP)

UDP is connectionless protocol.
When you a send a data or message, you don't know if it'll get there, it could get lost on the way.
If you send two messages out, you don't know what order they'll arrive in
a lot quicker, and the network card / OS have to do very little work to translate the data back from the packets
User Datagram protocol (UDP) has only the basic error checking mechanism using checksum


Examples:
Domain Name System (DNS UDP port 53)
streaming media applications such as IPTV or movies
Voice over IP (VoIP)
Trivial File Transfer Protocol (TFTP)
online multiplayer games

http://www.cyberciti.biz/faq/key-differences-between-tcp-and-udp-protocols/

• What is the difference between TCP and UDP? When would you use each of them?

What I'm looking for: someone who not only parrots the "connectionless vs. connection-oriented" idea, but can demonstrate they understand the reasons you might choose one or the other.


what advantages does UDP have over TCP?

UDP does not include a "handshake" in its protocols, it tends to be faster than TCP. UDP assumes that error checking and correction is either not necessary or performed in the application, avoiding the overhead of such processing at the network interface level.

Time-sensitive applications often use UDP because dropping packets is preferable to waiting for delayed packets, which may not be an acceptable option in a real-time system.

UDP advantage is primarily speed - no error detection or correction is used, and handshaking is not employed either so it is a faster transport mechanism (although it is not reliable).

http://wiki.answers.com/Q/What_advantage_does_UDP_have_over_TCP

• How do I find out running processes were associated with each open port on Linux?

How do I find out what process has open TCP port # 111 or UDP port 7000 under Linux using the CLI?
A port is nothing but an endpoint of communication used in computer networks. You have physical or wireless connections at the hardware level. At software or operating system level a port act as a logical construct that acts as communication port of network service such as SSH, HTTPD and more. TCP and UDP are the most common port.
https://www.cyberciti.biz/faq/what-process-has-open-linux-port/

• Introducing TCP/IP concepts: Selecting sockets

You can choose among the following types of sockets:

Stream
Datagram
Raw

Stream sockets perform like streams of information. There are no record lengths or character boundaries between data, so communicating processes must agree on their own mechanisms for distinguishing information. Usually, the process sending information sends the length of the data, followed by the data itself. The process receiving information reads the length and then loops, accepting data until all of it has been transferred. Because there are no boundaries in the data, multiple concurrent read or write socket calls of the same type, on the same stream socket, will yield unpredictable results. For example, if two concurrent read socket calls are issued on the same stream socket, there is no guarantee of the order or amount of data that each instance will receive. Stream sockets guarantee to deliver data in the order sent and without duplication. The stream socket defines a reliable connection service. Data is sent without error or duplication and is received in the order sent. Flow control is built in to avoid data overruns. No boundaries are imposed on the data; the data is treated as a stream of bytes.

Stream sockets are most common because the burden of transferring the data reliably is handled by TCP/IP, rather than by the application.

The datagram socket is a connectionless service. Datagrams are sent as independent packets. The service provides no guarantees. Data can be lost or duplicated, and datagrams can arrive out of order. The size of a datagram is limited to the size able to be sent in a single transaction. Currently, the default value is 8192 bytes, and the maximum value is 65535. The maximum size of a datagram is 65535 for UDP and 65535 bytes for raw

The raw socket allows direct access to lower layer protocols, such as IP and the ICMP. This interface is often used to test new protocol implementation, because the socket interface can be extended and new socket types defined to provide additional services

https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.hala001/itcsocketconselsoc.htm

• TCP/IP and UDP Comparison

Connection Versus Connectionless — TCP/IP is a connection-based protocol, while UDP is a connectionless protocol. In TCP/IP, the two ends of the communication link must be connected at all times during the communication. An application using UDP prepares a packet and sends it to the receiver's address without first checking to see if the receiver is ready to receive a packet. If the receiving end is not ready to receive a packet, the packet is lost.

Stream Versus Packet — TCP/IP is a stream-oriented protocol, while UDP is a packet-oriented protocol. This means that TCP/IP is considered to be a long stream of data that is transmitted from one end of the connection to the other end, and another long stream of data flowing in the opposite direction. The TCP/IP stack is responsible for breaking the stream of data into packets and sending those packets while the stack at the other end is responsible for reassembling the packets into a data stream using information in the packet headers. UDP, on the other hand, is a packet-oriented protocol where the application itself divides the data into packets and sends them to the other end. The other end does not have to reassemble the data into a stream. Note, some applications might present the data as a stream when the underlying protocol is UDP. However, this is the layering of an additional protocol on top of UDP, and it is not something inherent in the UDP protocol itself.

TCP/IP Is a Reliable Protocol, While UDP Is Unreliable — The packets that are sent by TCP/IP contain a unique sequence number. The starting sequence number is communicated to the other side at the beginning of communication. The receiver acknowledges each packet, and the acknowledgment contains the sequence number so that the sender knows which packet was acknowledged. This implies that any packets lost on the way can be retransmitted (the sender would know that they did not reach their destination because it had not received an acknowledgment). Also, packets that arrive out of sequence can be reassembled in the proper order by the receiver.
timeouts can be established because the sender knows (from the first few packets) how long it takes on average for a packet to be sent and its acknowledgment received. UDP, on the other hand, sends the packets and does not keep track of them. Thus, if packets arrive out of sequence, or are lost in transmission, the receiving end (or the sending end) has no way of knowing.
Note that "unreliable" is used in the sense of "not guaranteed to succeed" as opposed to "will fail a lot of the time." In practice, UDP is quite reliable as long as the receiving socket is active and is processing data as quickly as it arrives.

https://www.mathworks.com/help/instrument/tcpip-and-udp-comparison.html

How is TCP & UDP Checksum Calculated?

Volume Shadow Copy

Volume Shadow Copy is a service that creates and maintains snapshots (“shadow copies”) of disk volumes

If you accidentally delete 10 pages of your dissertation, you can right-click the document, choose Restore previous versions, and access a previous version of it.
You can open it (in read-only mode) or copy it to a new location.

If you accidentally delete a file or folder, you can right-click the containing folder, choose Restore previous versions, and open the folder as it appeared at the time a shadow copy was made (see screenshot below).
http://blog.szynalski.com/2009/11/23/volume-shadow-copy-system-restore/

The Windows Registry

The Windows Registry is a collection of databases of configuration settings.
The Windows Registry is used to store much of the information and settings for software programs, hardware devices, user preferences, operating system configurations, and much more.
Registry Editor can be accessed by executing regedit from the Command Prompt
http://pcsupport.about.com/od/termsr/p/registrywindows.htm

DHCP

• Dynamic Host Configuration Protocol (DHCP) is a network protocol that enables a server to automatically assign an IP address to a computer from a defined range of numbers (i.e., a scope) configured for a given network. When a computer uses a static IP address, it means that the computer is manually configured to use a specific IP address. One problem with static assignment, which can result from user error or inattention to detail, occurs when two computers are configured with the same IP address. This creates a conflict that results in loss of service. Using DHCP to dynamically assign IP addresses minimizes these conflicts. The purpose of DHCP is to ease administration of large networks. With static manual IP configuration you may get network conflict. http://kb.iu.edu/data/adov.html

• How does client know the IP address of DHCP server to send a DHCP Discover Message?

• DHCP Request Message

• How does DHCP (DORA) work?

• APIPA (Automatic Private IP Addressing)

Automatic Private IP Addressing (APIPA) is a feature in operating systems (such as Windows) that enables computers to automatically self-configure an IP address and subnet mask when their DHCP server isn’t reachable. The IP address range for APIPA is 169.254.0.1-169.254.255.254, with the subnet mask of 255.255.0.0.

https://study-ccna.com/apipa-automatic-private-ip-addressing/

labeled and unlabeled break statements

Break should be used either with loop or switch.
Further more Break has two forms Labeled and Unlabeled.
Good example of unlabaled break is, tradional use with switch, loop.
Labeled switch can also be used if we have labeled statements.
Simply using 'break' is compilation error.


Reference:
http://docs.oracle.com/javase/tutorial/java/nutsandbolts/branch.html

Marker interface

an interface with no methods is called as marker interface

ex:
interface test{ }

Serializable, Clonable, SingleThreadModel are called marker interfaces in java. these marker interface's give additional information about the behavior of the class.


Marker interface is an empty interface. Eg is Serializable. When a class
implements this interface then only we can serialize the object. i.e
we can save in the file. In other words any class which implements
serializable can be serialized which is the additional feature when
compared with an ordianary object.

Simillarly when a class is implementing java.rmi.Remote it can be
used as a Remote object.


Reference:
http://geekexplains.blogspot.com/2009/10/marker-interface-in-java-what-why-uses.html

• Since the ability of a Class's data to be serialized and de-serialized correctly is implementation specific, it is necessary to be able to assert whether serialization is possible for this class.

That is why the Marker Interface is provided and utilized.

For example, if your class members contain system-dependant information that is only relevant on one machine (such as hardware info) or only during the scope of one app server's life-cycle (like session Ids) then you are provide the ability to NOT mark it as serializable, so that no code will attempt to serialize and de-serialize, which would result in logic or runtime errors later on.
Whereas if your data consists of transportable data such as names or phone numbers, you can mark it serializeable, thus indicating that all manners of transport utilizing serialization and de-serialization may be employed on this data to allow it to be moved between machines etc.

http://www.linkedin.com/groups/Why-serialization-use-marker-interface-70526.S.5853381965264211970?view=&gid=70526&type=member&item=5853381965264211970&trk=eml-anet_dig-b_nd-pst_ttle-cn