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Syndication in Lotus Web Content Management - what it is and how it works

IBM Lotus Web Content Management facilitates an environment to design, author and maintain web content. A WCM deployment usually comprises more than one WCM instance. (Example: One WCM Authoring instance, one WCM staging instance and one WCM delivery instance). Content can be replicated between all the WCM instances using WCM Syndication.

Syndication is an integral part of IBM WCM responsible for replicating WCM libraries between WCM instances and keeping them in synch.
The source WCM instance from where content is replicated is known as at the Syndicator and the target WCM instance to where content is replicated is known as the Subscriber.

Syndication is based on the Information and Content Exchange (ICE) protocol, an XML-based protocol using HTTP as its transport mechanism.

Reference: An additional detail about the workings of the ICE protocol is available in the IBM developerworks article “Understanding syndication in IBM Workplace Web Content Management”.
URL: http://www.ibm.com/developerworks/lotus/library/wwcm-syndication/

All the items you work with as part of your WCM authoring environment (templates, components, content items, and so forth) are stored in WCM libraries. Syndication takes place at the WCM library level and replicates either All Items or All Live Items from the selected WCM library or libraries from the syndicator to the subscriber.

WCM libraries should be planned depending on how you plan to syndicate libraries between WCM instances. Planning WCM libraries should be done during the information architecture planning stage.

Syndication relationships can be of the following kinds –

• One way relationship
• Two way relationship
• Multiple relationships

One way relationship

In a one way Syndication relationship, the WCM libraries are always replicated from the Syndicator to the Subscriber in one direction. This type of setup is used when content the content creation is restricted to one environment.

Figure: One Way Syndication Relationship

Two way relationship

In a two way Syndication relationship, the WCM libraries can be syndicated in both directions. When enabling two-way syndication relationship, you must first establish the syndication relationship from the source WCM instance to the target WCM instance. Once the libraries have been replicated to target WCM instance, you can set up another syndication relationship for syndicate the content in the opposite direction.

Please note that you must use a consistent syndication strategy. For example, if syndicating "All items", then both syndication relationships must be syndicating "All items".

Figure: Two Way Syndication Relationship

Multiple relationships

In a multiple syndication relationship, you can have a WCM instance subscribe WCM libraries from multiple WCM instances as illustrated in the figure below. An example where this setup could be used - if you have the WCM authoring instance available in multiple locations and a single WCM delivery instance, you can use multiple syndication relationships to syndicate content to a single WCM delivery instance.

Figure: Multiple Syndication Relationships

Syndication Pre-requisites

Please remember the following important syndication pre-requisites –

1. The WCM syndicator instance and the subscriber instance should be configured to use the same LDAP environment to ensure that the WCM resource access permissions work properly.
2. The WCM syndicator and subscriber instances participating in the syndication process should be at the same WCM fixpack and ifix level for syndication to work as expected and to be in a supported state. WebSphere Portal ifixes do not have to be the same across servers.

Syndication - Important Things to Remember

The list of important things to remember for syndication have been provided below –

1. Things to remember when doing first time syndication–
   1. First-time syndication to an existing library is not supported. Attempting to syndicate a library to a subscriber that already has a library with the same name will result in an exception. Hence it is recommended not to use the default Web Content library. Although the libraries have the same name, they have different UUIDs.
   2. Access control settings are not part of syndication, and hence you must manually set access permissions on the subscriber's library when syndicating for the first time. If the library does not exist on the subscriber, it will be created during syndication. By default, no access control settings are specified on the new library, so you must set them manually before users can access content in the new library. It is not required that the settings on the subscriber's library match those on the Syndicators library, because you might want to provide different access for users on the subscribing server.
2. Information about a Library is only syndicated the first time syndication occurs and not on subsequent updates and rebuilds. If a library is renamed or library user access is changed, this information is not syndicated to the Subscriber. If you change the name of a library or change user access to a library, you will need to manually make the same changes to any subscriber libraries if you want the same settings on all your syndicated libraries. If content from one library (Library A) uses an item from another library (Library B), you must include both libraries in the Syndicator to ensure that all items are syndicated successfully. If you only include Library A in the Syndicator, any items in Library A that reference items in Library B are not syndicated, and syndication errors are generated.
3. If you add a new library to a Syndicator after the initial syndication you will need to click Update to force the new library to be syndicated immediately.
4. If you intend to syndicate a library that contains more than 10000 items, update the maximum Java heap size (at least 1024 MB) used by the portal application server on the subscriber machine.
5. Save the Syndicator before you save the Subscriber.
6. Although it is possible to set up more than one syndication relationship between the same WCM instances, there is no reason to do so. The additional syndication relationships are not required.
   
   WCM Event Log is a database table that was created to track changes made to all objects within WCM. This table is separate from the main WCM object library. The Event Log stores attributes about each WCM object. The Event Log can be used to flag candidates for syndication based on the lastModified date, the item gatherer and the library in which the object resides.
   
7. An item will fail to syndicate if an item it references has been deleted (but not purged). Purge the deletion and rebuild the subscription so that the deleted item is resent.