This is simply the table index, 0 to 10, identifying which of up to 11 configured RMON file-transfer server slots a given row represents; the description itself notes it's a placeholder rather than a meaningful data value. Because it's purely an index rather than descriptive data, an admin distinguishing between multiple configured RMON push destinations, such as a primary and backup file server, needs to pair this index with the server-name object to know which slot corresponds to which actual server. For example, index 0 might correspond to the primary RMON collection server while index 1 holds a secondary or backup server, distinguished only by this numeric slot value.