In /OSAMON the Summary screen provides Read and Write KB/sec values that are sourced either from RMF or SNMP depending on how monitoring has been defined. RMF will show the local partition and total rates. The advantage of SNMP is that it will show all partitions. Useful if you are port sharing. Both sets of values can be added to the resource monitoring to provide a long term view of activity. eg RMFChpReadRateTotal, RMFChpWriteRateTotal, ChpReadRateLpar5Min, ChpWriteRateLpar5Min
From a stack viewpoint (/STKMON) use DL to list interfaces and select the OSA interface to view the Interface Traffic Statistics. There are 5 one minute periods and 12 five minute periods showing bytes in/out. There will also be an application summary of interface usage based on a combined bytes in and out value.
Cheers, Jon