Choosing messaging providers for a mixed environment

If your existing or planned messaging environment involves both WebSphere® MQ and WebSphere Application Server systems, choose between the default messaging provider, the WebSphere MQ messaging provider, or a mixture of the two, by considering your messaging requirements, your business environment, and the needs of each messaging application.

About this task

For messaging between application servers, with interaction with a WebSphere MQ system, you can use the default messaging provider or the WebSphere MQ provider. Neither provider is necessarily better than the other. The choice of providers depends primarily on factors relating to your business environment and planned changes to that environment, and also on what each JMS application needs to do. Moreover, these two types of messaging providers are not mutually exclusive:

  • You can configure both types of providers within one cell.
  • Different applications can use the same, or different, providers.

Factors relating to your business environment include the following:

  • Messaging requirements
  • Existing skill set
  • Existing messaging infrastructure
  • Planned changes to that infrastructure

Configuring and managing your messaging infrastructure is simpler if you use just one provider. If your messaging is primarily in WebSphere MQ, you should probably choose the WebSphere MQ messaging provider. Similarly, if your messaging is primarily in WebSphere Application Server, you should probably choose the default messaging provider.

If your business environment does not clearly indicate that you should use just one provider, then you should consider using a mixture of the two, and choosing the most appropriate messaging provider for each application. A useful way of doing this is to identify the types of destinations (service integration bus, or WebSphere MQ queue or topic) that the application is using. If the application uses only bus destinations, the natural choice is to use the default messaging provider (solution DMP). If the application needs to communicate with one or more WebSphere MQ destinations, you can choose any of the following solutions depending upon your business environment, usage scenarios, and system topologies:
  • Use the WebSphere MQ messaging provider (solution MQP).
  • Use the default messaging provider to integrate a WebSphere MQ server (a WebSphere MQ queue manager or queue-sharing group) as a bus member (solution DMP interop bus member).
  • Use the default messaging provider to integrate a WebSphere MQ network as a foreign bus, by using WebSphere MQ links (solution DMP interop, foreign bus).

For more information about these solutions, see Interoperation with WebSphere MQ: Comparison of key features.

To help you choose between these solutions, several of the following steps contain tables in which each row represents a business or system requirement, and asterisks (*) indicate the solutions that are likely to be most effective for meeting the requirement. These tables are designed to provide general guidance, rather than to identify precisely a right solution. Most requirements have multiple possible solutions, and the absence of an asterisk does not necessarily mean that you cannot use that solution. To derive best guidance from using each of these tables:
  • Focus on the rows that reflect your most important requirements.
  • For all the rows that you consider, count the number of asterisks for each solution.
The solutions with the largest number of asterisks are likely to be the most effective.

Procedure

  1. If you have limited experience of WebSphere MQ or WebSphere Application Server, and are trying to decide which product best meets your messaging needs, see Comparison of WebSphere Application Server and WebSphere MQ messaging.
    Note: Whichever of these products you choose as the main focus for your messaging, you can still use either the default messaging provider or the WebSphere MQ provider for interoperation between the products.
  2. Consider your business environment, to see if you can use just one provider.
    In deciding which provider to use, consider the following constraints:
    • The current and future messaging requirements
    • The existing messaging infrastructure
    • The skill set that you have in your organization

    If the majority of your messaging is today performed in WebSphere MQ, continue with that approach and configure WebSphere MQ as an external JMS provider (that is, use the WebSphere MQ messaging provider) in WebSphere Application Server. If the JMS requirements of your WebSphere Application Server applications are limited, it is debatable whether using a service integration bus for those applications gives sufficient benefit.

    If you have messaging applications in WebSphere Application Server that have no requirement to interoperate with your WebSphere MQ network, use the default messaging provider (the service integration bus). If your WebSphere Application Server messaging requirements demand a tighter integration with WebSphere Application Server, the service integration bus provides the following benefits:

    • Integrated administration
    • WebSphere Application Server high availability capabilities
    • WebSphere Application Server scalability

    If you choose to use the default messaging provider to interoperate between service integration and WebSphere MQ, be aware that there is an added cost involved in converting messages between service integration format and WebSphere MQ format.

    Also consider the following messaging scenarios:

    • A large installed backbone of WebSphere MQ queue managers, perhaps with message broker product.

      If you want to use WebSphere Application Server to run a newly introduced messaging application, you can deploy a WebSphere Application Server (JMS) messaging application that will exchange messages with an existing application that uses a WebSphere MQ queue or topic.

    • A WebSphere Application Server installation, perhaps with existing web and enterprise applications, but no WebSphere Application Server messaging application.

      If you have no existing messaging infrastructure, you can deploy a WebSphere Application Server (JMS) messaging application to exchange messages with an existing WebSphere Application Server messaging application that uses a service integration bus destination.

    • An infrastructure that uses WebSphere Application Server to connect WebSphere Application Server messaging applications.

      Introduce WebSphere Application Server (JMS) messaging between a pair of WebSphere Application Server applications.

    • An infrastructure that includes both WebSphere MQ and service integration buses. This might be the result of a merger, or because the message traffic tends to be from WebSphere Application Server to WebSphere Application Server, or from WebSphere MQ to WebSphere MQ, but not typically between WebSphere Application Server and WebSphere MQ.

      Deploy a WebSphere Application Server (JMS) messaging application to exchange messages with an application that uses a WebSphere MQ queue or topic.

    • A WebSphere Process Server or WebSphere Enterprise Service Bus infrastructure, which uses Service Component Architecture (SCA).

      You can choose either a WebSphere MQ or a service integration bus binding for your SCA components.

  3. If your business environment does not clearly indicate that you should use just one messaging provider, use a mixture of the two and choose the most appropriate provider for each application, based upon the destination types that the application uses.

    The application might need to exchange messages with existing partner applications or services that use one or more known destinations of known type. Alternatively, the partner applications or services might not yet be deployed and the choice of destination type might still be open, in which case the solution architect needs to decide how best to connect the applications or services together.

    If the application uses multiple destinations, there are four possible outcomes:

    Note: If there is no clear business or technical reason why the application uses WebSphere MQ destinations rather than bus destinations, and the partner application is also a WebSphere Application Server JMS application, consider migrating the existing destinations to service integration so that the application uses only bus destinations.
  4. If the application uses only bus destinations, configure the application and its JMS resources to use the default messaging provider.
  5. If the application uses only WebSphere MQ destinations (queues or topics), use the following checklist to determine which provider solution to use.
    Table 1. Provider checklist for an application that uses only WebSphere MQ destinations . The first column of this table lists the checklist questions for the business or system requirements for an application that uses only WebSphere MQ destinations. In the second column, the requirements that are met by the WebSphere MQ messaging provider (MQP) solution are marked with an asterisk. In the third column, the requirements that are met by the default messaging provider bus member (DMP interop, bus member) solution are marked with an asterisk. In the fourth column, the requirements that are met by the default messaging provider foreign bus (DMP interop, foreign bus) solution are marked with an asterisk. In columns two to four, any requirements that are not met by the solution shown in that column are not marked with an asterisk.
    Question: MQP DMP interop, bus member DMP interop, foreign bus
    Is performance critical?

    (If so, use WebSphere MQ directly, rather than perform message conversion.)

    		 *
    Does the application have to send or receive large messages (that is, messages > 500k.)? *
    Is location transparency desirable for simplifying programming and deployment of applications? * *
    Does the application have to consume from a WebSphere MQ queue, the configuration of which is fixed?

    (That is, the queue cannot be moved to service integration and you do not want to deploy a push-style WebSphere MQ application to send messages to a bus destination.)

    		 * *
    Is the partner application a JMS application that will run outside WebSphere Application Server, as a bus or WebSphere MQ client?

    (Do not mix service integration and WebSphere MQ unless you have to do so; a pure WebSphere MQ or service integration solution is simpler and avoids the cost of converting messages between service integration and WebSphere MQ formats.)

    		 *
    Is the partner application a non-JMS (non-WebSphere Application Server) application?

    (Wherever possible choose a pure WebSphere MQ or service integration solution. Use the MQI WebSphere MQ client, or the XMS WebSphere MQ client, or the XMS bus client depending on your API preference.)

    		 *
    Do you prefer traffic passing between your WebSphere MQ network and WebSphere Application Server applications to be funneled into a single long-running connection? *
    Do you want to use the high availability features of WebSphere Application Server? *
    Is XA two-phase commit (2PC) needed between the application and a WebSphere MQ queue-sharing group? * See 1 * See 2
    Is XA two-phase commit (2PC) needed between the application and a WebSphere MQ cluster? *
    Are you using the WebSphere Enterprise Service Bus to mediate messages from, or deliver them to, a WebSphere MQ queue?

    (For example, using WebSphere Business Integration adapters, or connecting to a service provider such as CICS®.)

    		 *
    Does the application have to consume from a WebSphere MQ queue, the configuration of which is fixed?

    (that is, the queue cannot be moved to service integration and you don't want to deploy a push-style WebSphere MQ application to send messages to a bus destination.)

    		 * *  
    Note:
    • 1 Provided that WebSphere MQ Version 7.0.1 is used.
    • 2 XA two-phase commit can be used with the WebSphere MQ link, but it only covers the sending of the message to the WebSphere MQ link. It does not cover the subsequent sending of the message from the WebSphere MQ link to a WebSphere MQ queue manager using store and forwards.
  6. If the application uses a mixture of bus and WebSphere MQ destinations, for example consuming from service integration and sending to WebSphere MQ, then either of the default messaging provider interoperation models can support this by using a single connection factory or activation specification. Use the following checklist to help you decide between a bus member and a foreign bus solution.
    Table 2. Provider checklist for an application that uses a mixture of bus and WebSphere MQ destinations . The first column of this table lists the checklist questions for the business or system requirements for an application that uses a mixture of bus and WebSphere MQ destinations. In the second column, the requirements that are met by the default messaging provider bus member (DMP interop, bus member) solution are marked with an asterisk. In the third column, the requirements that are met by the default messaging provider foreign bus (DMP interop, foreign bus) solution are marked with an asterisk. In columns two and three, any requirements that are not met by the solution shown in that column are not marked with an asterisk.
    Question: DMP interop, bus member DMP interop, foreign bus
    Does the application have to consume from a WebSphere MQ shared queue? *
    Do you prefer traffic passing between your WebSphere MQ network and WebSphere Application Server applications to be funneled into a single long-running connection? *
    Do you need distributed WebSphere MQ in versions earlier than WebSphere Application Server Version 7 and WebSphere MQ Version 7? *
    Do you want store and forward capabilities to allow the application to continue to send messages when the WebSphere MQ queue manager is unavailable? *
    Do you prefer not to configure server connection channels?

    (This is because they open a port, which might be seen as a security risk.)

    		 See 1
    Do you prefer to define a server connection channel, rather than a pair of sender and receiver channels? *
    Do you only want to use bindings connections? *  
    Note:
    • 1 This is only applicable if you want to send messages from WebSphere MQ to the service integration bus via the WebSphere MQ link, although you do need to open a port to your application server. Sending messages from the service integration bus to WebSphere MQ via the WebSphere MQ link requires a port to be opened to the queue manager through your firewall.
  7. If the destination types are not yet known, decide the relative priorities of the known concerns then use the following checklist to assess how well each of them is addressed by the possible provider solutions.

    The underlying choice is what type of destinations this application should use. The destination types are not yet fixed, so any of the four solutions is possible, but as a general rule you should aim for solution DMP or MQP, because a pure WebSphere MQ or service integration solution is simpler and avoids the cost of converting messages between service integration and WebSphere MQ formats.

    Table 3. Provider checklist for an application for which the destination types are not yet known . The first column of this table lists the checklist questions for the business or system requirements for an application for which the destination types are not yet known. In the second column, the requirements that are met by the default messaging provider (DMP) solution are marked with an asterisk. In the third column, the requirements that are met by the WebSphere MQ messaging provider (MQP) solution are marked with an asterisk. In the fourth column, the requirements that are met by the default messaging provider bus member (DMP interop, bus member) solution are marked with an asterisk. In the fifth column, the requirements that are met by the default messaging provider foreign bus (DMP interop, foreign bus) solution are marked with an asterisk. In columns two to five, any requirements that are not met by the solution shown in that column are not marked with an asterisk.
    Question: DMP MQP DMP interop, bus member DMP interop, foreign bus
    Do you have an existing base of strong skills in managing WebSphere MQ? * * *
    Do you want management of all messaging to be handled by the WebSphere MQ team? *
    Do you have administrators skilled in WebSphere Application Server but not in WebSphere MQ? *
    Do you want a messaging product with a large installed base (including references) and a wide choice of ISV tools? *
    Are you reluctant to buy a separately licensed product in addition to WebSphere Application Server? *
    Are you reluctant to install and manage a separate product in addition to WebSphere Application Server? *
    Are you already using IBM® Integration Bus, known in earlier releases as WebSphere Message Broker?Are you already using WebSphere Message Broker?

    (If so, you need WebSphere MQ anyway).

    		 * * *
    Does the application need to send or receive large messages (that is, messages > 500k.)? *
    Is location transparency desirable for simplifying programming and deployment of applications? * * *
    Do the throughput requirements need multiple parallel channels or routes? * * *
    Is the partner application a JMS application that will also run in WebSphere Application Server?

    (Service integration runs in the WebSphere Application Server application server. On distributed platforms that means it is in-process. )

    		 *
    Is the partner application a JMS application that will run outside WebSphere Application Server, as a bus or WebSphere MQ client?

    (Do not mix service integration and WebSphere MQ unless you have to do so; a pure WebSphere MQ or service integration solution is simpler and avoids the cost of converting messages between service integration and WebSphere MQ formats.)

    		 * *
    Is the partner application a non-JMS (non-WebSphere Application Server) application?

    (Wherever possible choose a pure WebSphere MQ or service integration solution. Use the MQI WebSphere MQ client, or the XMS WebSphere MQ client, or the XMS bus client depending on your API preference.)

    		 * *
    Is maintenance of strict message order important? *
    Does the application require the flexibility and convenience of a WebSphere MQ cluster?

    (WebSphere MQ clustering makes administration simpler and provides selective parallelism of clustered queues. That is, instances of a clustered queue can be created on any (but not necessarily all) queue managers in the WebSphere MQ cluster. Messages sent to the clustered queue can be addressed to a specific instance of the queue, or allowed to select an instance dynamically based on workload management statistics. WebSphere Application Server clustering provides some of this flexibility, but you cannot create partitions of a bus destination on a subset of the messaging engines in a cluster bus member.)

    		 * * *
    Does the application need the level of high availability provided by WebSphere MQ for z/OS® shared queues? * * *
    Do you want to use the high availability or scalability features of WebSphere Application Server clustering? * * *