interview q&a mq

8/8/2019 Interview Q&A MQ

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http://activexpert.blog.co.in/2009/04/08/websphere-mq-interview-questions/ (Joseph's blog)

http://javaj2eeplanet.blogspot.com/2009/02/websphere-mq-interview-questions_26.html

http://activexpert.blog.co.in/category/technical/interview-questions/

http://www-1.ibm.com/software/integration/wmq/index.html?S_TACT=105AD02W&S_CMP=campaign

[email protected]

post resume for the JOB

What is MQ and what does it do?Ans. MQ stands for MESSAGE QUEUEING. WebSphere MQ allowsapplication programs to use message queuing to participate in message-

driven processing. Application programs can communicate across different

platforms by using the appropriate message queuing software products.What is Message driven process?Ans .When messages arrive on a queue, they can automatically start anapplication using triggering. If necessary, the applications can be stopped

when the message (or messages) have been processed.

What are advantages of the MQ?Ans. 1.Integration.

2. Asynchrony

3. Assured Delivery4. Scalability.

How does it support the Integration?Ans. Because the MQ is independent of the Operating System you use i.e. itmay be Windows, Solaris,AIX.It is independent of the protocol (i.e. TCP/IP,

LU6.2, SNA, NetBIOS, UDP).It is not required that both the sender andreceiver should be running on the same platform

What is Asynchrony?Ans.With message queuing, the exchange of messages between the sendingand receiving programs is independent of time. This means that the sending

and receiving application programs are decoupled; the sender can continueprocessing without having to wait for the receiver to acknowledge receipt of

the message. The target application does not even have to be running when

the message is sent. It can retrieve the message after it is has been started.

What are the hardware and Software requirements for MQInstallation in AIX?Ans. WebSphere MQ for AIX, V5.3 runs on any machine that supports theAIX V4.3.3 PowerPC 32.bit, or AIX V5.1 Power 32 bit only operating

system.Disk Storage: Typical storage requirements are as follows:1 Server installation: 50 MB2. Client installation:15 MB

3 Data storage (server): 50 MB4. Data storage (client): 5 MB.

Software Requirements:


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Operating system: The operating systems supported by WebSphere MQ forAIX, V5.3 are:

1. AIX V4.3.3, with PTF U472177, running in a 32 bit environment, on 32 or64 bit hardware.

2. AIX V5.1, with PTFs U476879, U477366, U477367 and U477368, and

APAR fix IY29345 running 32 bit kernel running on 32 or 64 bit hardware.3. AIX V5.1, with PTF U476879, U477366, U477367 and U477368, and APARfix IY29345 running 64 bit kernel running on 64 bit hardware.Connectivity The network protocols supported by WebSphere MQ for AIX,V5.3 are:

1. TCP/IP2. SNA LU 6.2.Databases: DB2 7.1, 7.2Oracle 8i and 9iSybase v12 or v 12.5Java: If you want to use the Java Messaging Support, you need the JavaRuntime Environment Version 1.3 or later

What are the software and hardware requirements for installing MQon Windows?Ans: MQ v 5.3 supports Windows 2000, Windows 2000XP,Windows2000NT,Windows 2003 SE, Windows 2003EE.Disk Storage: Typical storage requirements are as follows:1 Server installation: 50 MB2. Client installation:15 MB3 Data storage (server): 50 MB

4. Data storage (client): 5 MB.Connectivity The network protocols supported by WebSphere MQ for AIX,V5.3 are:

1. TCP/IP

2. SNA LU 6.2.

3. LU 6.2

4. NetBIOSDatabases: DB2 7.1, 7.2Oracle 8i and 9iSybase v12 or v 12.5

Java: If you want to use the Java Messaging Support, you need the JavaRuntime Environment Version 1.3 or later

what is a Message and what does it contain?


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Ans: A message is a string of bytes that is meaningful to the applicationsthat use it. Messages are used to transfer information from one application

program to another (or between different parts of the same application). Theapplications can be running on the same platform, or on different platforms.

WebSphere MQ messages have two parts:

1. The application data.The content and structure of the application datais defined by the application programs that use it.2. A message descriptor.The message descriptor identifies the messageand contains additional control information, such as the type of message and

the priority assigned to the message by the sending application. WebSphere

MQ defines the format of the message descriptor. For a complete descriptionof the message descriptor,What is the Max Length of the message does MQ support/Ans: The default maximum message length is 4 MB, although you canincrease this to a maximum length of100 MB (where 1 MB equals 1 048576 bytes).

What is the difference between Persistent and Non PersistentMessages?Ans: In Web Sphere MQ, messages can be either persistent or nonpersistent. Persistent messages are logged and can be recovered in theevent of a WebSphere MQ failure. Thus, persistent messages are guaranteed

to be delivered once and only once. Nonpersistent messages are not logged.

Web Sphere still guarantees to deliver them not more than once, but it doesnot promise to deliver them once.What is the effect of using Persistant messages?Ans: Persistent messages are usually logged. Logging messages reduces the

performance of your application, so use persistent messages for essentialdata only. If the data in a message can be discarded if the queue managerstops or fails, use a nonpersistent message.WebSphere MQ messages:

Messages are made up of Two parts: Message descriptor, Application dataTypes of messages?Datagram: A Message sent with no response expected.

Request: A Message sent for which a response is expected.

Reply: A Response Message for a requested message.

Report: A Message that describes the occurrence or eventEx COA/CODSizes ?

Qmanager10000 Msgs Maxmsglength4 MbQueue5000 Msgs Maxmsglength4 Mb

What is the attribute used to see the Message length?Ans: MaxMsgLengthWhat is MQ Client?


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Ans: A Web Sphere MQ client is a component that allows an applicationrunning on a system to issue MQI calls to a queue manager running on

another system. The output from the call is sent back to the client, whichpasses it back to the application.

What is MQ Server?

Ans: A Web Sphere MQ server is a queue manager that provides queuingservices to one or more clients. All the Web Sphere MQ objects, for examplequeues, exist only on the queue manager machine (the Web Sphere MQserver machine), and not on the client. A Web Sphere MQ server can also

support local Web Sphere MQApplicationsWhat are the Objects used in Web sphere MQ?Ans: 1. Queue Manager 2. Queues

3. Channels 4. Processes 5. Name lists.Mention the No ofCharacters required for creating names of the MQobjects?Ans: For MQ Channels it is 20 Characters

For Remaining objects it is 48 characters.

What about is the Default port number for MQ Queue Manager?Ans:1414Difference between MQSC commands and Control commands?

MQSC Commands - These commands are used to handle the admin related

functions for the components that are present in the MQ Series. In general

MQSC commands are used for creating and maintaining Message channels,Queue Managers, Clusters etc

Control Commands - These commands are used to manage the processes

and services that are helpful in the functioning of the MQ Series. In generalthese commands are used for Channel listener, Channel Initiator, Triggermonitor etc

Is the MQSC attributes are Case sensitive?Ans: MQSC commands, including their attributes, can be written inuppercase or lowercase. Object names in MQSC commands are folded touppercase (that is, QUEUE and queue are not differentiated), unless the

names are enclosed within single quotation marks. If quotation marks are

not used, the object is processed with a name in uppercase.

SCRIPT COMMANDS:-After entering in to queue manager we can find script commands.

Script commands are same for every queue manager.

(These Commands should be used in CAPITAL LETTERS)

yDEFINE :-To define/create MQ manager objects like queue,

Channels, process, and listener.

yALTER :-to update or modify the existing objects

yDISPLAY :-to view all the properties of a particular object or toDisplay all objects


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yDELETE :-to delete created objects

yCLEAR :-to clear the message from the queue

yEND :-to come out of the queue manageryPING :-to check whether other side channel / queue manager is ready

to accept our request.

ySTART :- to start the particular channel or listenerySTOP :-to stop particular channel or listener

yREFRESH :-used to refresh the security every time after giving or

executing, set mgr or command for queue manager or objectyRESET :-used to reset channel,cluster,queue manager

yRESOLVE :-to resolve the channel which is in indoubt state

ySUSPEND :-to suspend a queue manager from a cluster environment

yRESUME :-to remove a queue manager from a cluster environmentHow can we write the MQSC commands that have too manyparameters/A

ns: For commands that have too many parameters to fit on one line, usecontinuation characters to indicate that a command is continued on thefollowing line:

1. A minus sign (-) indicates that the command is to be continued from thestart of _ the following line.2. A plus sign (+) indicates that the command is to be continued from thefirst nonblank character on the following line.

What is programmable command format (PCF) commands?

These commands are issued from a programme for local or remote

administration done by programmers.

What are commands used for creating the Queue manager from theCommand prompt?Ans: crtmqm-q -d MY.DEFAULT.XMIT.QUEUE -u DEAD.LETTER.QUEUE QM1Here

-q used to define the Queue manager QM1 as a Default Queue manager-d is used to define the default transmission Queue-u is used to define the default dead letter queue.How can U make the existing Queue Manager as an default QueueManager?Ans: On Windows systems, use the Web Sphere MQ Services snap-in todisplay the properties of the queue manager, and check the Make queuemanager the default box. You need to stop and restart the queue managerfor the change to take effect.Where are the backup files are present after creating the QueueManager?Ans: Windows systems: If you use Web Sphere MQ for Windows NT andWindows 2000, configuration information is stored in the Windows Registry.


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UNIX Systems: 1. When you install the product, the Web Sphere MQconfiguration file (mqs.ini) is created. It contains a list of queue managers

that is updated each time you create or delete a queue manager. There isone mqs.ini file per node.

2. When you create a new queue manager, a new queue manager

configuration file (qm.ini) is automatically created. This containsconfiguration parameters for the queue manager.What is the command used for starting the Queue Manager?Ans: strmqmQMNameWhat is the command used for stopping the Queue manager?Ans: endmqm -w QMNameThe command waits until all applications have stopped and the queue

manager has ended.

endmqm i QMNameThis type of shutdown does not wait for applications to disconnect from thequeue manager.

Whats the message code for Stopping a Queue Manager?AMQ4044 Queue manager stopping

What is the command used to delete the QueueManager?Ans: dltmqmQMNameDisplay the attributes of the Queue Manager QM1?Ans: runmqsc QM1

Display qmgrWhat is Queue?Ans: A queue is a data structure used to store messages. A queue managerowns each queue. The queue manager is responsible for maintaining the

queues it owns, and for storing all the messages it receives onto theappropriate queuesWhat is the Default max Queue depth?Ans5000Types of Queues?

Local Queue Remote Queues Alias QueuesModel Queue Dynamic Queues Cluster Queues.Queue: A safe place to store messages for Prior-To-Delivery, it belongs tothe Qmgr to which the application is connected.

Model Queue: Model queue is a template of a queue definition that useswhen creating a dynamic queue.

Alias Queue: Queue definition, which is Alias to an actual Local or RemoteQ. Used for security and easy maintenance.

Remote Queue: Object that defines a Queue belongs to another Q Manager(Logical Def).Initiation Queue: An initiation queue is a local queue to which the queuemanager writes a trigger message when certain conditions are met on

another local queue


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Dynamic Queue: Such a queue is defined "on the fly" when the applicationneeds it. Dynamic queues may be retained by the queue manager or

automatically deleted when the application program ends. Use- To storeintermediate results.Cluster Queue: Custer queue is a local queue that is known throughout a

cluster of queue managers.Reply-To-Queue: A request message must contain the name of the queueinto which the responding program must put the Reply Message.Queue Manager: Provides Messaging services and manages the Queues,Channels, and Processes that belongs to it.Alias Q Manager: Queue-manager aliases, are created using a remote-queue definition with a blank RNAME.What are the attributes required for the Remote Queue Definition?Ans: 1.Name of the Queue 2. Transmission Queue Name.

3. Remote QueueManager name 4. Remote Local Queue NameHow can U define Queues in MQ?Ans: Queues are defined to Web Sphere MQ using:

1. The MQSC command DEFINE

2. The PCF Create Queue command

What is Transmission Queue?Ans: Transmission queues are queues that temporarily store messages thatare destined for a remote queue manager. You must define at least one

transmission queue for each remote queue manager to which the localqueue manager is to send messages directly.What is Initiation Queues?Ans: Initiation queues are queues that are used in triggering. A queue

manager puts a trigger message on an initiation queue when a trigger eventoccurs. A trigger event is a logical combination of conditions that is detectedby a queue manager.What is Dead Letter Queue?Ans: A dead-letter (undelivered-message) queue is a queue that storesmessages that cannot be routed to their correct destinations. This occurs

when, for example, the destination queue is full. The supplied dead-letterqueue is called SYSTEM.DEAD.LETTER.QUEUE. For distributed queuing,define a dead-letter queue on each queue manager involved.

What is the Max size that Queues support in MQ v5.3?A

ns.They support around 2GBof SizeHow can u create a Transmission Queue from a local Queue?

Ans. Change the usage attribute from normal to TransmissionQ38.Define a Local Queue LQ using the MQSCCommands in the QMQM1Ans: runmqsc QM1

Define qlocal (LQ)


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What are the Difference B/W Predefined &Dynamic Queues?Ans: Queues can be characterized by the way they are created:1. Predefined queues are created by an administrator using theappropriate MQSC or PCF commands. Predefined queues are permanent;

they exist independently of the applications that use them and survive Web

Sphere MQ restarts.2 Dynamic queues are created when an application issues an MQOPENrequest specifying the name of a model queue. The queue created is basedon a template queue definition, which is called a model queue.

What is the Algorithm followed in retrieving the Messages from theQueue?Ans: 1.First-in-first-out (FIFO).

2.Message priority, as defined in the message descriptor. Messages that have thesame priority are retrieved on a FIFO basis.

3. A program request for a specific message.

What is Process Definition and what are the attributes does itcontain?Ans: A process definition object defines an application that starts inresponse to a trigger event on a WebSphere MQ queue manager. The

process definition attributes include the application ID, the applicationtype, and data specific to the application.What is intercommunication and its components to send message ?

What is Intercommunication?Ans: In Web Sphere MQ, intercommunication means sending messages fromone Queue manager to another. The receiving queue manager could be on

the same machine or another; nearby or on the other side of the world. Itcould be running on the same platform as the local queue manager, or could

be on any of the platforms supported by Web Sphere MQ. This is called a

distributed environment.Message channels Message channel agentsTransmission queues Channel initiators and listeners

Channel-exit programs

What is Distributed Queue Management (DQM).Web Sphere MQ handles communication in a distributed environment suchas this using DQM.The local queue manager is sometimes called the sourcequeue manager and the remote queue manager is sometimes called the

target queue manager or the partner queue manager.What is the Objects required for the DQM?Ans: On source QueueManager:1. Transmission Queue 2. Remote queue definition.3. Dead Letter Queue(recommended) 4. Sender ChannelOn Target Queue Manager1. Local Queue 2. Dead Letter Queue 3. Receiver Channel 4.Listenr


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***.The sender and receiver channels names should be same.

What is channel and mention different types of channels in MQ?Ans: Channels are objects that provide a communication path from onequeue manager to another. Channels are used in distributed queuing to

move messages from one queue manager to another. They shield

applications from the underlying communications protocols. The queuemanagers might exist on the same, or different, platforms. Different types ofChannels:

1. Sender-Receiver Channels2. Requester-Server Channels3. Client Connection channels4. Server Connection Channels.5. Cluster Sender.

6. Cluster Receiver ChannelsWhat are MQI channels and there types?

MQI channels are the channels that carry messages from MQ Client

application to the MQ server and vice versa.They are Bi-directional Channels

1. Server-connection 2. Client-connectionHow many Channel Combinations?

1.Sender-receiver Channel 4.Requester-server Channel2.Requester-sender Channel 5. Server-receiver Channel3.Cluster-Sender- Receiver Channel 6.Client-Server Channel

What are the attributes required for the Sender Channel?Ans: 1. The Name of the Channel 4.Transport Type

2. The Connection name 5.Scyexit

What are different Channel status?

Ans: Channel Status:1. Inactive 3.Retrying2. Running 4.StoppedWhat about Initializing &Binding states?Ans: Before running state first the channel will initializes the listener & Bindswith the Receiver Channel then it goes into running mode.Tell me Some Channel Attributes?

Batch Heartbeat Interval (BATCHHB): This heartbeat interval allows a

sending channel to verify that the receiving channel is still active just beforecommitting a batch of messages. If the receiving channel is not active, the

batch can be backed out rather than becoming in-doubt, Batch interval

(BATCHINT), Batch size (BATCHSZ), Channel type (CHLTYPE), Cluster(CLUSTER), Cluster namelist (CLUSNL), Connection name (CONNAME),Convert message (CONVERT), Disconnect interval (DISCINT), Heartbeatinterval (HBINT), KeepAlive Interval (KAINT), Long retry count (LONGRTY),Long retry interval (LONGTMR), Maximum message length (MAXMSGL)Why is Channel RETRYINT attribute used?

If a message is places in DLQ because of put inhibited or queue full

condition, the DLQ handler attempts to put the message back to the


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destination queue. This interval is called as RETRYINT by default the retry

interval is 60 seconds.

Receiver Cluster Receiver RequesterWhat is channel disconnect interval?

This is a time-out attribute, specified in seconds, for the server, cluster-

sender, and cluster-receiver channels. The interval is measured from thepoint at which a batch ends, that is when the batch size is reached or when

the batch interval expires and the transmission queue becomes empty. If no

messages arrive on the transmission queue during the specified time

interval, the channel closes downExplain the channel attribute BATCHSIZE?

BATCHSIZE denotes the maximum number of messages that can be sent

through a channel before taking a checkpoint. This parameter is valid only

for channels with a channel type (CHLTYPE) of SDR, SVR, RCVR, RQSTR,CLUSSDR, or CLUSRCVR. The value must be in the range 1 through 9999.

What is BATCHHEARTBEAT INTERVAL?

Ans: The batch heartbeat interval allows a sending channel to verify that thereceiving channel is still active just before committing a batch of messages,

so that if the receiving channel is not active, the batch can be backed outrather than becoming in-doubt, as would otherwise be the case. By backingout the batch, themessages remain available for processing so they could, for example, be

redirected to another channel.What is Keep Alive Interval?Ans: The Keep Alive Interval parameter is used to specify a time-out valuefor a channel. The Keep Alive Interval parameter is a value passed to the

communications stack specifying the Keep Alive timing for the channel. Itallows you to specify a different keep alive value for each channel. The value

indicates a time, in seconds, and must be in the range 0 to 99999.

What is LONG Retry count?Ans: Specify the maximum number of times that the channel is to tryallocating a session to its partner. If the initial allocation attempt fails, theshort retry count number is decremented and the channel retries the

remaining number of times.What are the ways to start a channel?

Use the MQSC command START CHANNEL

Use the control command runmqchl to start the channel as a process

Use the channel initiator to trigger the channelType of channel states:Inactive and Current- Stopped, Starting, Retrying and ActiveWhat are the three options for stopping channels?

QUIESCE FORCE TERMINATEWhat are the components of message channel?

A queue manager to communicate with another queue manager uses

message channel. The components of a message channel are


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1. Sender Message channel agent: Sender MCA is a program that transfersmessages from a transmission queue to a communication link2. Receiver MCA: It transfers messages from the communication link intothe target queue

3. Communication protocol: Responsible for transferring messages A

message channel is unidirectional.What is Message Channel agent (MCA)?Ans: A message channel agent (MCA) is a program that controls the sendingand receiving of messages. There is one message channel agent at each end

of a channel. One MCA takes messages from the transmission queue and

puts them on the communication link. The other MCA receives messages anddelivers them onto a queue on the remote queue manager.A message channel agent is called a caller MCA if it initiated thecommunication; otherwise it is called a responder MCA.Q52.What is Channel initiator and Listeners?Ans: A channel initiator acts as a trigger monitor for sender channels,because a transmission queue may be defined as a triggered queue. When a

message arrives on a transmission queue that satisfies the triggering criteria

for that queue, a message is sent to the initiation queue, triggering the

channel initiator to start theappropriate sender channel. You can also start server channels in this way if

you specified the connection name of the partner in the channel definition.

This means that channels can be started automatically, based uponmessages arriving on the appropriate transmission queue.You need a listener program to start receiving (responder) MCAs.Responder MCAs are started in response to a startup request from the caller

MCA; the channel listener detects incoming network requests and starts theassociated channel.Channel Errors?Due to:1. Xmitq is set to get disabled 2. Network Issues

3.QueueManager Stopped 4. Listener is not running

5.TriggerTurned OffExplain Channel-Exit programs and what are the types?

Channel-exit programs are called at defined places in the processing carried

out by MCA programs

Security Exit: You can use security exit programs to verify that the partnerat the other end of a channel is genuine

Message Exit: Message Exit can be used for Encryption on the link, message

data conversion, validation of user ID,

Message-retry Exit: Message-retry exit is called when an attempt to open

the target queue is unsuccessfulSender and receiver Exit: You can use the send and receive exits to perform

tasks such as data compression and decompression

Channel auto-definition ExitTransport-retry Exit


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What is the Different Logging Methods available?Ans: There are two different types available1. Circular: The circular logging is used for restart recovery. It is the defaultlogging method. Circular is used in Development and Testing Queues.

Circular logging keeps all restart Data in a ring of log files. Logging fills the

first file in the ring, then moves on to the and so on, until all the files arefull. It then goes back to the first file in the ring and starts This continues aslong as the product is in use, and has the advantage that you never run outof log files.2. Linear: Linear logging gives you both restart recovery and mediarecovery. It is used in Production. Linear logging keeps the log data in acontinuous Sequence of files. Space is not reused, so you can always

retrieve any record logged from the time that the queue manager was

created. As disk space is finite, you might have to think about some form of

archiving. It is an administrative task to manage your disk space for the log,reusing Or extending the existing space as necessary.

What is the Default location where the logs are stored and mentionthe default sizes?Ans: Default location:

Windows: C:\Program Files\IBM\WebSphere MQ\log\qmgrUNIX:/var/mqm/log

What is the log file size?Ans: In Web Sphere MQ for Windows NT and Win 2000, the minimum valueis 32, and the maximum is 16 384. The default value is 256, giving a defaultlog size of1 MB.In Web Sphere MQ for UNIX systems, the minimum value is 64, and the

maximum is 16 384. The default value is 1024, giving a default log size of 4MB.How will you change the log file size?Ans ; You cannot change the log file size. For this you need to drop and re-create the queuemanager. The number of log files primary & secondary can be changed but you need torestart the Q manager for the changes to take effect.

what is the number for log primary and secondary file allocated?Ans: Primary log files: The number of primary log files to be allocated is 3by default the minimum is 2 and MAX in Win 253 / Unix 510Secondary log files: The number of secondary log files to be allocated is 2by default the minimum is 1 and MAX in Win 252 / Unix 509

What is the command used for creating the listener?Ans: crtmqlsr -t tcp -m QMNAME -p portnoWhat is the commands used for running listener in 5.3 Version?Ans: runmqlsr -t tcp -m QMNAME -p portnoWhat is command used to perform task on the MQ services?Ans: amqmdainWhat are commands used on the Command server?


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Ans: 1.strmqcsv: to start the command server2. dspmqcsv: to display the command server3. endmqcsv: To end the command server.

Is there is any chance for the Message lost?Ans: If the target queuemanager doesn.t contain the dead letter queue

defined and if the messages are running on a fast channel and of nonpersistant,Then there is a chance of the message loss.What is the command that is used to provide authorization for theclients?Ans:setmqaut-m QMName -t queue -n Queuename -p GUEST +allWhat are the common errors u get in DQM? Explain how to resolve ?Ans:mqrc 2058: MQRC_Q_MGR_NAME_ERRORMqrc 2059: MQRC_Q_MGR_NOT_AVAILABLE.Mqrc 2033: MQRC_NO_MSG_AVAILABLE.Mqrc 2085: MQRC_UNKNOWN_OBJECT_NAME.Mqrc 2009: MQRC_CONNECTION_BROKEN.Mqrc 2043: MQRC_OBJECT_TYPE_ERROR.Mqrc 2086: MQRC_UNKNOWN_OBJECT_Q_MGR.Mqrc 2035: MQRC_NOT_AUTHORIZED.What are different modes in which a application can connect to aQueuemanager?Ans: 1.Binding mode: In binding mode, also known as server connection,the communication to the queue manager utilizes inter-processcommunications. One of the key factors that should be kept in mind is thatbinding mode is available only to programs running on the MQSeries server

that hosts the queue manager. A program using binding mode will not runfrom an MQSeries client machine. Binding mode is a fast and efficient way tointeract with MQSeries. Certain Facilities, such as XA transaction co-

ordination by queue manager, are available only in binding mode.

2. Client Connection: Client connection uses a TCP/IP connection to theMQSeriesServer and enables communications with the queue manager.Programs using client connections can run on an MQSeries client machine aswell as on an MQSeries server machine. Client connections use client

channels on the queue manager to communicate with the queue manager.

The client connection does not support XA transaction coordination by the

queue manager.What are the different types of messaging systems used by JMS?Ans: JMS applications use either the point-to-point (PTP) orpublish/subscribe style of messaging.Point-to-Point: Point-to-point messaging involves working with queues ofmessages. The sender sends messages to a specific queue to be consumednormally by a single receiver. In point-to-point communication, a message


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has at most one recipient. A sending client addresses the message to the

queue that holds the messages for the intended (receiving) client.

Publish/Subscribe: In contrast to the point-to-point model ofcommunication, the publish/subscribe model enables the delivery of a

message to multiple recipients. A sending client addresses, or publishes, the

message to a topic to which multiple clients can be subscribed. There can bemultiple publishers, as well as subscribers, to a topic.Is It Possible to use one transmission Queue for the multiplemessage channels?Ans: It is possible to define more than one channel per transmission queue,but only one of these channels can be active at any one time. This isrecommended for the provision of alternative routes between queue

managers for traffic balancing and link failure corrective action. A

transmission queue cannot be used by another channel if the previous

channel to use it terminated leaving a batch of messages in-doubt at thesending end.

What is the command used to test whether the channel is active ornot?Ans: runmqscQMName

Ping channel (channel name).What are the administrative commands that are used in Publish and Subscribe?Ans:Thestrmqbrkcommandis usedtostartabroker. Thefirsttimethis commandis runonaqueue manager, alltherelevantMQSeries objects areautomaticallycreated.--------strmqbrk -m MYQMGRNAMEThe dspmqbrkcommand is used to check the status of the broker. Possiblestates are: starting, running, stopping, quiescing, not active and ended

abnormally.

--------dspmqbrk -m MYQMGRNAME

The endmqbrkcommand is used to stop a broker. There are two options:-crequests a controlled shutdown (default), -i requests an immediateshutdown.

-------endmqbrk -i -m MYQMGRNAMEWhat is multiple hoping?Ans: If there is no direct communication link between the source queuemanager and the target queue manager, it is possible to pass through one

or more intermediate queue managers on the way to the target queue

manager. This is known as a multi-hop.What is Local administration and Remote administration?

Local Administration: Means carrying out administration tasks on any

queue managers you have defined on your local system.

Remote Administration: This allows you to issue commands from yourlocal system that are processed on another system. For example, you can

issue a remote command to change a queue definition on a remote queue

manager. You do not have to log on to that system, although you do need to

have the appropriate channels defined. The queue manager and commandserver on the target system must be running


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Difference between Control Commands used in Windows and other Os?

Control commands on are case sensitive other OS but Windows they can beused any way.What is MQOO_BIND_ON_OPEN option on the MQOPEN call ?

When this attribute is set it forces all the messages sent to this queue to be

sent to the same instance of the queue (go to the same queue in cluster)Difference between MQPUT and MQPUT1 call ?The MQPUT1 call always operates as though MQOO_BIND_NOT_FIXED were

in effect, that is, it always invokes the workload management routine.When is Channel security exit program called?

Are called at MCA initiation and termination

Stopping unauthorized queue managers putting messages on your queuesUse OS security, Object Authority Manager (OAM) on WebSphere MQ user-written proceduresWhat happens ifDEAD letter Queue is not defined?

If dead letter queue are not defined the Messages are placed on the

Transmission Queue and the Queue Manager become InactiveExplain Remote queue definitions? Advantages?These are definitions for queues that are owned by another queue manager

Advantages: The advantage of remote queue definitions is that they enablean application to put a message to a remote queue without having to specifythe name of the remote queue or the remote queue manager, or the name

of the transmission queue. This gives you location independence.What happens if channel terminates when fast non-persistent messages are intransit?

If a channel terminates while fast, non-persistent messages are in transit,

the messages are lost and it is up to the application to arrange for their

recovery if required. If the receiving channel cannot put the message to itsdestination queue then it is placed on the dead letter queue, if one has been

defined. If not, the message is discarded.What happens when a message cannot be delivered?

Message-retry: If the MCA is unable to put a message to the target queuefor a reason that could be transitory (for example, because the queue is

full), the MCA has the option to wait and retry the operation later

Return-to-sender: If message-retry was unsuccessful, or a different type of

error was encountered, the MCA can send the message back to theoriginator

Dead-letter queue: If a message cannot be delivered or returned, it is put on

to the dead-letter queue (DLQ). You can use the DLQ handler to process themessageRecovery scenario Disk Drive Full, damaged Queue manager object,Damaged single object, Automatic media recovery failureMQ ensures that messages are not lost by maintaining records (logs) of the

activities of the queue managers that handle the receipt, transmission, and

delivery of messages


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How to Process Messages from the Dead-letter-Queue?

We can Process the DLQ messages using runmqdlq command for sendingmessages to the destination Queues or target Queues. Use the runmqdlq

command to start the dead-letter queue (DLQ) handler, which monitors and

handles messages on a dead-letter queue.runmqdlqQNameQMgrName

Use the Dead-Letter-Queue-Handler to perform various actions on selected

messages by specifying a set of rules that can both select a message and

define the action to be performed on that message.The runmqdlq command takes its input from stdin. When the command is

processed, the results and a summary are put into a report that is sent to

stdout.Which field of the MQDLH structure contains a reason code that identifies why themessage is on the DLQ?

Reason field

What is completion code(MQCC) and reason code(MQRC)?Completion code gives the status of the current transaction it can be 0, 1, 2.

0- for Successful completion (MQCC_OK), 1- Warning (MQCC_WARNING), 2-call failed (MQCC_FAILED).

Reason code is that which gives the reason for which the transactionfails it can be MQRC_NONE, MQRC_BACKED_OUT etc.What is Correl ID?

This is a byte string that the application can use to relate one message toanother, or to relate the message to other unit of work that the applicationis performing. The correlation identifier is a permanent property of themessage, and persists across restarts of the queue manager

Explain commit and Back Out units of work?When a program puts a message on a queue within a unit of work, thatmessage is made visible to other programs only when the program commits

the unit of work.Commit: To commit a unit of work, all updates must be successful to

preserve data integrity. If the program detects an error and decides that theput operation should not be made permanent, it can back out the unit of

work.

Back Out: When a program performs a back out, WebSphere MQ restores

the queue by removing the messages that were put on the queue by thatunit of work. The way in which the program performs the commit and back

out operations depends on the environment in which the program is runningBackoutCount (MQLONG)?

This is a count of the number of times that the message has been previouslyreturned by the MQGET call as part of a unit of work, and subsequently

backed out. BackoutCount is the number of times the application tried and

failed to put the messages in the Queue

What is segmentation and explain segmentation Flag?


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When a message is too big for a queue, an attempt to put the message on

the queue usually fails. Segmentation is a technique whereby the queue

manager or application splits the message into smaller pieces calledsegments, and places each segment on the queue as a separate physical

message. The application that retrieves the message can either retrieve the

segments one by one, or request the queue manager to reassemble thesegments into a single message that is returned by the MQGET call.What are Namelist? when do you use it?

A namelist is a WebSphere MQ object that contains a list of other

WebSphere MQ objects. Typically, namelists are usedBy trigger monitors, where they are used to identify a group of queues.Namelists are also used with queue manager clusters to maintain a list of

clusters referred to by more than one WebSphere MQ object.The advantage of using a namelist is that it is maintained independently of

applications; it can be updated without stopping any of the applications that

use it. Also, if one application fails, the namelist is not affected and otherapplications can continue using it. Namelists are also used with queue

manager clusters to maintain a list of clusters referred to by more than one

WebSphere MQ object

What are name services?The name service is an installable service that provides support to the queue

manager for looking up the name of the queue manager that owns a

specified queue.What is Local units of work (uses a single-phase commit process) and Global unitof Work (uses a two-phase commit process)?

Local unit of work: Units of work that involve only the queue manager are

called local units of work. Syncpoint coordination is provided by the queuemanager itself (internal coordination) using a single-phase commit process.Use global units of work when you also need to include updates to resources

belonging to other resource managers. Here the coordination can be internal

or external to the queue manager uses a two-phase commitHow will we start a command server?

Depending on the value of the queue manager attribute, SCMDSERV, the

command server is either started automatically when the queue manager

starts, or must be started manually.Start: Using strmqcsvsaturn.queue.manager where saturn.queue.manager is

the QM name

Display: dspmqcsv Stop: endmqcsvWhen we use CCSID attribute of the ALTER QMGR command to change the CCSIDof the QM what are the components that need to be restarted?

Stop and restart the queue manager, stop and restart command server (Acommand server processes command messages) and channel programsWhat is a MQ Series Queue manager Configuration file (qm.ini)?

A queue manager configuration file (qm.ini) to effect changes for specific

queue managers. There is one qm.ini file for each queue manager on the


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node. (A queue manager configuration file, qm.ini, contains config

information relevant to a specific queue manager. There is one queue

manager configuration file for each queue manager. The qm.ini file isautomatically created when the queue manager with which it is associated is

created. For example, the path and the name for a configuration file for a

queue manager called QMNAME is:/var/mqm/qmgrs/QMNAME/qm.ini)What is name transformation in naming a Queue manager Configuration File?

A qm.ini file is held in the root of the directory tree occupied by the queue

manager. For example, the path and the name for a configuration file for a

queue manager called QMNAME is: /var/mqm/qmgrs/QMNAME/qm.ini A

directory name is generated based on the queue manager name. Thisprocess is known as name transformation.What is a Websphere MQ configuration file (mqs.ini)?

Contains information relevant to all the queue managers on the node. It iscreated automatically during installation (The WebSphere MQ configuration

file, mqs.ini, contains information relevant to all the queue managers on the

node. It is created automatically during installation. The mqs.ini file forWebSphere MQ for UNIX systems is in the /var/mqm directory. It contains: v

The names of the queue managers v The name of the default queuemanager The location of the files associated with each of them)How can we edit the configuration files?

Automatically using commands that change the configuration of queuemanagers on the node, Manually using a standard text editorWhen security checks are made?

Connecting to the queue manager (MQCONN or MQCONNX calls), Opening

the object (MQOPEN or MQPUT1 calls), Putting and getting messages(MQPUT or MQGET calls), Closing the object (MQCLOSE)What is FFST?

First Failure Support Technology ForMQSeries for UNIX systems, FFST

information is recorded in a file in the /var/mqm/errors directory. Theseerrors are normally severe, unrecoverable errors, and indicate either a

configuration problem with the system or an MQSeries internal error. The

files are named AMQnnnnn.mm.FDC, where: nnnnn Is the ID of the process

reporting the error mm Is a sequence number, normally 0 When a processcreates an FFST record, it also sends a record to syslog. The record contains

the name of the FFST file to assist in automatic problem trackingCreating Damaged Objects Using Log files?

1.Rcdmqimg

:Use this command to write an image of an object, or group ofobjects, to the log for use in media recovery. This command can only be

used when using linear logging.

Use the associated command rcrmqobj to recreate the object from theimage.2.Rcrmqobj: Use this command to recreate an object, or group of objects,from their images contained in the log. This command can only be used

when using linear logging


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Use the associated command, rcdmqimg, to record the object images to the

log.

Types ofrecovery:Restart recovery: When you stop WebSphere MQ in a planned way.

Crash recovery: When a failure stops WebSphere MQ.

Media recovery: To restore damaged objects.What are the locations and files of the Error Logging?

MQ Series Level ErrorsC:\ProgramFiles\IBM\WebSphere MQ\errors AMQERR01.LOG,

AMQERR02.LOG, AMQERR03.LOG

Qmanager Level errorsC:\ProgramFiles\IBM\WebSphere MQ\Qmgrs\errors AMQERR01.LOG,

AMQERR02.LOG, AMQERR03.LOG

\errorsWhat are the different types of security services available in MQ Series?

Identification & Authentication

Access control The access control service protects critical resources in asystem by limiting access only to authorized users and their applications.Confidentiality The confidentiality service protects sensitive information

from unauthorized disclosureData integrity The data integrity service detects whether there has been

unauthorized modification of data. There are two ways in which data might

be altered: accidentally, through hardware and transmission errors, or

because of a deliberate attack, Non-repudiation.

Commands For Authorization:

1.setmqaut: Command used to change the authorizations to a profile, objector class of objects. Authorizations can be granted to, or revoked from, anynumber of principals or groups.

2.dspmqaut: Command to display the current authorizations to a specified

object. If a user ID is a member of more than one group, this command

displays the combined authorizations of all the groups.Only one group or principal can be specified.3.dmpmqaut: Command to dump the current authorizations to a specifiedobject.What are the different methods handled by MQ Series for securing a message?

Cryptography Message digests

Digital signatures Digital certificatesPublic Key Infrastructure (PKI)What is Cryptography, Why and where it is used in MQ Series?

Cryptography is the process of converting between readable text, called

plaintext, and an unreadable form, called cipher text.

The sender converts the plaintext message to cipher text. This part of the

process is called encryption (sometimes encipherment).The cipher text istransmitted to the receiver. The receiver converts the cipher text message


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back to its plaintext form. This part of the process is called decryption

(sometimes decipherment).

The conversion involves a sequence of mathematical operations that changethe appearance of the message during transmission but do not affect the

content. Cryptographic techniques can ensure confidentiality and protect

messages against unauthorized viewing (eavesdropping), because anencrypted message is not understandable. Digital signatures, which providean assurance of message integrity, use encryption techniques.What is a Message Digest, Digital Signature and Digital Certificate?

Message digest: Is also known as a Message Authentication Code (MAC),

because it can provide assurance that the message has not been modified.The message digest is sent with the message itself. The receiver can

generate a digest for the message and compare it with the senders digest.If the two digests are the same, this verifies the integrity of the message.

Any tampering with the message during transmission almost certainlyresults in a different message digest.Digital signature: Is formed by encrypting a particular representation of a

message the encryption uses the private key of the signatory and, for

efficiency, usually operates on a message digest rather than the messageitself. Digital signatures vary with the data being signed, unlike handwritten

signatures, which do not depend on the content of the document being

signed. If two different messages are signed digitally by the same entity, the

two signatures differ, but both signatures can be verified with the same

public key, that is, the public key of the entity that signed the messages.Digital certificates: Provide protection against impersonation, because a

digital certificate binds a public key to its owner, whether that owner is an

individual, a queue manager, or some other entity. Digital certificates arealso known as public key certificates, because they give you assurancesabout the ownership of a public key when you use an asymmetric key

scheme.What is a Secure Sockets Layer (SSL), where it is used?

The Secure Sockets Layer (SSL) provides an industry standard protocol fortransmitting data in a secure manner over an insecure network. The SSL

protocol is widely deployed in both Internet and Intranet applications. SSLdefines methods for authentication, data encryption, and message integrity

for a reliable transport protocol, usually TCP/IP.What are Cipher Suites and Cipher Specs in SSL?

Cipher Suite: Is a suite of cryptographic algorithms used by an SSLconnection. A suite comprises three distinct algorithms. The key exchangeand authentication algorithm, used during the SSL handshake. Theencryption algorithm, used to encipher the data.The MAC (MessageAuthentication Code) algorithm, used to generate the message digest.


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Cipher Spec: Identifies the combination of the encryption algorithm and MAC

algorithm. Both ends of an SSL connection must agree the same CipherSpec

to be able to communicate.What are the steps to be followed in working with SSL on an UNIX environment?

1.Setting up a key repository 2.Working with a key repository

3.Obtaining personal certificates 4.Managing digital certificates5.Configuring for cryptographic hardware 6.Mapping DNs to user IDs

7.Adding personal certificates to a key repositoryWebsphere MQ installation naming consideration?

Ensure that the machine name does not contain any spaces. If you insatall insuch a machine you cannot create and Queue managers. Names for userId

and group must no longer that 20 charactersWhat is CCSID?

This defines the character set of character data in the message. If you wantto set this character set to that of the queue manager, you can set this field

to the constant MQCCSI_Q_MGR or MQCCSI_INHERIT. When you get a

message from a queue, compare the value of the CodedCharSetId field withthe value that your application is expecting. If the two values differ, youmight need to convert any character data in the message or use a data-

conversion message exit if one is availableChannel: Communication Paths between Queue Managers.Tell Some Default objects: (43 objects)Queues: SYSTEM.DEFAULT.LOCAL QUEUE

SYSTEM.DEFAULT.MODEL.QUEUESYSTEM.DEFAULT.REMOTE.QUEUE

SYSTEM.DEFAULT.ALIAS.QUEUESYSTEM.DEFAULT.INITIATION.QUEUESYSTEM.DEAD.LETTER.QUEUE

ChannelQueues: SYSTEM.CHANNEL.INITQ

SYSTEM.CHANNEL.SYNCQ

Admin Queues:SYSTEM.ADMIN.ACCOUNTING.QUEUESYSTEM.ADMIN.ACTIVITY.QUEUE

SYSTEM.ADMIN.COMMAND.QUEUE

SYSTEM.ADMIN.STATISTICS.QUEUE

SYSTEM.ADMIN.TRACE.ROUTE.QUEUEChannels:SYSTEM.AUTO.RECEIVER SYSTEM.AUTO.SVRCONN

SYSTEM.DEF.CLUSRCVR SYSTEM.DEF.CLUSSDR

SYSTEM.DEF.RECEIVER SYSTEM.DEF.REQUESTERSYSTEM.DEF.SENDER SYSTEM.DEF.SERVERSYSTEM.DEF.SVRCONN

Listeners:SYSTEM.DEFAULT.LISTENER.TCPSYSTEM.DEFAULT.LISTENER.SPXSYSTEM.DEFAULT.LISTENER.NETBIOS

SYSTEM.DEFAULT.LISTENER.LU62


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Process Def: SYSTEM.DEFAULT.PROCESS

Services: SYSTEM.DEFAULT.SERVICE SYSTEM.BROKER

Name Lists:SYSTEM.DEFAULT.NAMELISEventQueues: SYSTEM.ADMIN.CHANNEL.EVENT

SYSTEM.ADMIN.LOGGER.EVENT

SYSTEM.ADMIN.PERFM.EVENTSYSTEM.ADMIN.QMGR.EVENT

What are advantages of creating Aliases? Why do we create Alias?

When sending messages: Re mapping the queue-manager name when

sending messages, Altering or specifying the transmission queue when

sending messages, Determining the destination when receiving messages,Using a queue manager as a gateway into the cluster. Gives different

application different levels of access authority to the target Queue Allowsdifferent applications to work with the same queue in different way

Simplifies maintenance, migration and workload balanceWhat are the parameters required to put a message on a queue (or) putting a

message on queue parameters?Requires a Connection handler (Hconn), a Queue handler (Hobj), adescription of the message that you want to put on the queue (MQMD),

Control information, message length, the message data itselfGetting messages for a queue?

You can remove a message from the queue so that other programs can nolonger see the message, you can copy a message, leaving the original

message on the queue. This is known as browsing. You can remove the

message once you have browsed it. In both cases, you use the MQGET call,

but first your application must be connected to the queue manager, and youmust use the MQOPEN call to open the queueWhat happens when a message is put in a PUT-INHIBITED Queue?

The messages are put in the dead letter queue. If a channel is unable to put

a message to the target queue because that queue is full or put inhibited,the channel can retry the operation a number of times (specified in the

message-retry count attribute) at a given time interval (specified in the

message-retry interval attribute). Alternatively, you can write your own

message-retry exit that determines which circumstances cause a retry, andthe number of attempts made. The channel goes to PAUSED state while

waiting for the message-retry interval to finishWhat is syncpoints?

Syncpoint coordination is the process by which units of work are eithercommitted or backed out with data integrity. The decision to commit or back

out the changes is taken, in the simplest case, at the end of a transaction.

However, it can be more useful for an application to synchronize datachanges at other logical points within a transaction.These logical points are called syncpoints (or synchronization points) and theperiod of processing a set of updates between two syncpoints is called a unit

of work


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In-doubt Channels? How will you resolve this ?

An in-doubt channel is a channel that is indoubt with the remote channelabout which messages has been sent and received

Solution: We can do Commit or Rollback the messages which are in doubt.

Scenarios:

Queue open failed?*Reason: On an MQCONN or MQCONNX call, the value specified for the

QMgrName parameter is not valid or not known

*Resolution: we must correct the configuration information

Queue not found?

*Reason Code 2085 MQRC_UNKNOWN_OBJECT_NAME*Resolution: check for the Queue name in the QManager if not found define

it.Messages sent to DLQ?

*Reason code: 2218 Message too big for Channel*Investigation: Examine the contents of the dead-letter queue. Each

message is contained in a structure that describes why the message was put

to the queue, and to where it was originally addressed. Also look at previous

error messages to see if the attempt to put messages to a dead-letter queuefailed.

*Resolution: change the channel size as required, if the channel is a cluster

channel then do a REFRESH cluster so that it will reflect to the other QMs,

then reprocess the message

Message piling(FULL) up in a Queue?*Investigation: Check for the log files

(/var/mqm/qmgrs//errors/*.log), The messages were not

being processed because of very high workload.*Resolution: SSL*Authentication failure:

The SSL client does not have a certificateA certificate has expired or is not yet activeA certificate is not supportedA certificate is corruptedMay be ssl version upgradation

Channel refuses to run or channel retry?

*Reason: A mismatch of name between a sending and receiving channels,Incorrect channel type specified, A receiver channel might be in stopped

state, the connection might not be defined Correctly, there might be a

problem with communication software.

*Resolution: Alter the Queue and REFRESH the cluster to reflect the change

in the information stored in the partial repository


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Handling messages more than 4 MB?

Increase the Queue and Queue manager MaxMsgLength attributes, Usesegmented messages (Messages can be segmented by either the application

or the Queue manager), use reference message.DQM: DISTRIBUTED QUEUEING MANAGEMENT

Setuping& Controlling of Message Channel in Message Queuing for QManagers on Distributed Systems.What is the SSL Version used in WMQ5.3?

Version 3.0NPMSPEEDFAST. What happens if the channel goes down?

Nonpersistent message speed (NPMSPEED) It is used to specify the speed at

which nonpersistent messages are to be sent. It can take on two valueseither normal or fast. The default is fast, which means that nonpersistentmessages on a channel are not transferred within transactions. Nonpersistent messages are lost if there is a transmission failure or if the

channel stops when the messages are in transit.

What is SSL?Secure Sockets Layer (SSL) is a protocol designed to allow the transmission

of secure data over an insecure network. SSL makes use of digitalcertificates to enable authentication of the partner. It also uses encryption to

prevent eavesdropping and hash functions to enable detection of tampering.It can be used with both MCA channels for queue manager to queue

manager communication and MQI channels for client applications connecting

to a queue managerWhat are the algorithms in SSL?

A CipherSuite is a suite of cryptographic algorithms used by an SSLconnection. A suite comprises three distinct algorithms:

The key exchange and authentication algorithm, used during the SSLhandshakeThe encryption algorithm, used to encipher the dataThe MAC (Message Authentication Code) algorithm, used to generate the

message digest

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