Global Cache Blocks Received - the number of blocks received from the remote instance over the hardware interconnect. This occurs when a process requests a consistent read for a data block that is not in its local cache. Oracle sends a request to another instance. Once the buffer has been received, this statistic is incremented. This statistic is a sum of another two statistics:
Global Cache blocks received = gc current blocks received + gc cr blocks received
gc current blocks received - is the Global Cache statistic. It is the number of current blocks received from the remote instance over the hardware interconnect. This statistics derives from v$sysstat.VALUE 'gc current blocks received'
gc cr blocks received - is the Global Cache statistic. It is the number of consistent read blocks received from the remote instance over the hardware interconnect. This statistics derives from v$sysstat.VALUE 'gc cr blocks received'
See also Current Block Gets vs Consistent Read (cr) Block Gets for explanation of the difference between Current and CR blocks.