How does the distributed clock work in infinispan/jboss cluster.

Can some one please guide me. I have read a little bit about the total order messaging and vector clock. 

I have extended the infinispan API for freshness Aware caching. I have assumed the time is synchronized all the time and timestamps are comparable. But I want to know how the timestamp work in Infinispan in distributed environment, specially when  the communication among the cluster nodes  is in synchronous mode.

Regards

Meena