This object represents the number of octets to be
placed into the ARR Data portion of the response message.
This value is passed to the RTT Echo Server via a
field in the ARR Header.
For non-ARR RTT request/response (i.e. ipIcmpecho)
this value will be set by the agent to match the
size of rttMonEchoAdminPktDataRequestSize, when
native payloads are supported.
REMEMBER: The ARR Header overhead is not included
in this value.
This object is only supported by SNA protocols.