Skip to main content

IBM Websphere MQ - Resolving problems if your MQTT client fails to connect - Middleware News


IBM Websphere MQ - Resolving problems if your MQTT client fails to connect - Middleware News

If your MQTT client cannot connect to a telemetry channel, there might be a number of reasons.

Procedure

Consider the following reasons to diagnose the problem with an MQTT client failing to connect:
  • Check that the queue manager and MQXR service are running.
    Start the queue manager. By default, the MQXR service should start with the queue manager. If you configured the MQXR service control to start manually, you might have to start the service from the Services folder. For more information about starting the MQXR service, 
  • Check that the telemetry channel and telemetry service are defined and running correctly.
    You can manually define the MQXR service and set the default transmit queue of the queue manager to SYSTEM.MQTT.TRANSMIT.QUEUE, which takes precedence over an existing default transmit queue. This makes the queue manager suitable for Telemetry. Alternatively, you might want to consider running the Define sample configuration wizard from the Telemetry welcome page, if you have not done so already.
  • Have you written your own client?
    If so, did you write your client application with the MQTT v3 protocol and not the v5 protocol? Try to isolate the problem by running the MQTT client utility.
  • Do you have a valid client identifier name?
    When connecting to WebSphere MQ, the MQTT client identifier should be less than 23 characters, and contain only alphabetic characters, numeric characters, and the period (.), forward slash (/), underscore (_), and percent sign (%).
  • Did you connect your MQTT client and exhaust the MQTT keep alive interval?
    The keep alive attribute is the interval in milliseconds after which, the MQTT client is disconnected due to inactivity. If the MQXR service does not receive any communication from the client within the keep alive interval, it disconnects from the client.
  • Is a large number of MQTT clients trying to connect to a telemetry channel at the same time?
    Every telemetry channel has a backlog attribute. This is the number of concurrent connection requests that the telemetry channel supports. Ensure that the value is not set to a number that is less than the number of MQTT clients trying to connect.
  • Check that the TCP/IP connection is still active.

Comments

Post a Comment

adsrerrapop

Popular posts from this blog

Troubleshooting Java/JMS SSL Configurations - Middleware News

 This document is intended to help diagnose WebSphere MQ V7 Java™ or JMS SSL setup errors. It lists most of the common configuration errors that can cause an SSL connection from a Java/JMS client to a queue manager to fail, and gives the course of action to resolve the problem. In each case the error can be diagnosed by a combination of the error seen in the client log - either a console output, trace file or SystemOut.log file - and the queue manager's error logs. The document is quite long, so the easiest way to find the potential error is to search for one of the errors seen in this list, then filter this list using the error from the opposite end of the channel. All cases here assume that 2-way authentication is being attempted (SSLCAUTH set to REQUIRED on the queue manager's SVRCONN channel). This is the default, and the errors are very similar for 1-way authentication (SSLCAUTH set to OPTIONAL). Symptom Instructions on collecting documentation...
Post a Comment
Read more

Using telnet to test connectivity between IBM Websphere MQ Client and MQ server - Middleware News

You are having trouble connecting a WebSphere MQ client to a MQ server, receiving errors that you can not connect to the MQ queue manager. One of the first things to determine is if the two machines can communicate, and using the telnet tool is one way to accomplish it. Symptom Receiving errors which state that a queue manager is not found or not available. Connection errors. For example: AMQ9213, AMQ9524, AMQ9202 or AMQ9508 or MQRC =2059 0x0000080b MQRC_Q_MGR_NOT_AVAILABLE. Please note, this is by no means an exclusive list of errors related to this type a problem but just a sample of some of the more common error messages and codes that might occur. Cause One possible cause is that the two machines can not communicate. May be the IP address or hostname was not properly specified by the MQ client. The port number might be incorrect. A queue manager is not running at the desired host. The queue manager could be running, but the corresponding listener is not runnin...
Post a Comment
Read more

IBM Websphere MQ interview Questions Part 5

MQ Series: - It is an IBM web sphere product which is evolved in 1990’s. MQ series does transportation from one point to other. It is an EAI tool (Middle ware) VERSIONS:-5.0, 5.1, 5.3, 6.0, 7.0(new version). The currently using version is 6.2 Note: – MQ series supports more than 35+ operating systems. It is platform Independent. For every OS we have different MQ series software’s. But the functionality of MQ series Default path for installing MQ series is:- C: programfiles\BM\clipse\SDK30 C: programfiles\IBM\WebsphereMQ After installation it will create a group and user. Some middleware technologies are Tibco, SAP XI. MQ series deals with two things, they are OBJECTS, SERVICES. In OBJECTS we have • QUEUES • CHANNELS • PROCESS • AUTHENTICATION • QUERY MANAGER. In SERVICES we have LISTENERS. Objects: – objects are used to handle the transactions with the help of services. QUEUE MANAGER maintains all the objects and services. QUEUE: – it is a database structure ...
143 comments
Read more