IpData is a read-only Counter32 giving the number of frames belonging to the user-defined 'IpData' protocol group for this MAC-to-MAC conversation, where the MIB lets the operator decide which individual protocols get bundled under that group name to view traffic patterns and profiles at the node level; a value of 4294967294 means the count is unknown. Because the grouping is user-definable rather than fixed, an admin can tailor this counter to track whatever cluster of protocols matters at their site, then watch the resulting count for the pair 00:1A:2B:3C:4D:01/00:1A:2B:3C:4D:02 for shifts in that custom pattern rather than tracking each underlying protocol separately. If a site defines the 'IpData' group to bundle a handful of business-critical protocols and this counter for the pair 00:1A:2B:3C:4D:01/00:1A:2B:3C:4D:02 suddenly drops toward zero, that is the signal that the applications behind that group have stopped generating traffic.