EO_OUTBOUND_PARALLEL Definition in SAP PI 7.31 System

Hi Experts,

I was working on performance tuning for PI 7.31.

I am not able to set the parameter EO_OUTBOUND_PARALLEL under the category TUNING. I am using the subparamter as  Sender/Receiver ID defined under the tcode sxmsif.

Is there any document or note to impliment this?

Error while trying to save it:

Sender/ReceiverID doesnt exist.

Please advise.

Thanks,
Sushama