DB_UNIQUE_NAME=boston
FAL_SERVER=boston2
LOG_ARCHIVE_CONFIG='DG_CONFIG=(boston,boston2,denver)'
LOG_ARCHIVE_DEST_1='LOCATION=USE_DB_RECOVERY_FILE_DEST
VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=boston'
LOG_ARCHIVE_DEST_2='SERVICE=boston2 SYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=boston2'

Cascading Physical Standby Database

DB_UNIQUE_NAME=boston2
FAL_SERVER=boston
LOG_ARCHIVE_CONFIG= 'DG_CONFIG=(boston,boston2,denver)'
LOG_ARCHIVE_DEST_1='LOCATION= USE_DB_RECOVERY_FILE_DEST
VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=boston2'
LOG_ARCHIVE_DEST_2= 'SERVICE=denver VALID_FOR=(STANDBY_LOGFILES,STANDBY_ROLE) DB_UNIQUE_NAME=denver'

Cascaded Physical Standby Database

DB_UNIQUE_NAME=denver
FAL_SERVER=boston2
LOG_ARCHIVE_CONFIG='DG_CONFIG=(boston,boston2,denver)'
LOG_ARCHIVE_DEST_1='LOCATION= USE_DB_RECOVERY_FILE_DEST VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=denver'