SMON
SMON (System MONitor) is an Oracle background process created when you start a database instance. The SMON process performs instance recovery, cleans up after dirty shutdowns and coalesces adjacent free extents into larger free extents.
SMON wakes up every 5 minutes to perform housekeeping activities. SMON must always be running for an instance. If not, the instance will terminate.
[edit]Check process

The following Unix/Linux command is used to check if the SMON process is running:
$ ps -ef | grep smon
oracle   31144     1  0 11:10 ?        00:00:00 ora_smon_orcl


PMON
PMON (Process MONitor) is an Oracle background process created when you start a database instance. The PMON process will free up resources
if a user process fails (eg. release database locks).
PMON normally wakes up every 3 seconds to perform its housekeeping activities. PMON must always be running for an instance. If not, the
instance will terminate.

How to check RAC database status in UNIX
pmon on both nodes.  check using srvctl status command
[oracle@rac2 ~]$ ps -eaf | grep pmon



Configuring the network Interface 

/etc/udev/rules.d/70-persistent-net.rules
/etc/sysconfig/network-scripts/eth---