In order for the caching to work following conditions must be met
- The producer portlet must be developed using Standard Portlet API. The Portlet developed using IBM Portlet API wont return caching structure
- The value of wsrp.caching.enabled property must be set to true in Configuration Service on both producer and consumer portal server. If it is set to true the producer portal will return cache-control structure in response. And the consumer portlet will cache markup in fragment based on the values of cache control in the response it received from the producer
The cache settings are defined in the portlet.xml, they set two things first what should be duration of cache and second is if this cache is user specific or can be shared in multiple users.