The instance identifier for the ping object is:

        proto.addr.count.size.timeout

where

        proto   1 for IP, 2 for Appletalk
        addr    an IP address
        count   the number of echo requests to send
        size    bytes in each echo request packet
        timeout seconds to wait for a reply to each echo request

For example, setting

  iso.org.dod.inet.priv.enter.cisco.local.system.ping.1.131.108.2.238.45.64.2

to any value will cause 45 64-byte IP pings to be sent to
131.108.2.238, with a timeout value of 2 seconds.

The value returned from a SNMP Set is an integer specifying the number
of echo replies received.  The value returned from a SNMP Get is 0, as
no pings are done.  SNMP GetNext skips this object.

The implementation of this object is marginal, so expect it to
misbehave if you don't invoke it correctly.  Also, while the pings are
running, the snmp server is unable to process other requests.