This Counter64 field tallies the bytes on the reverse direction of this bidirectional CES tunnel that were accepted on ingress, specifically traffic that passed the tunnel's ingress bandwidth-profile check as in-profile (green) and was let into the tunnel without remarking. Because this is the currently open, still-accumulating measurement interval that keeps climbing until its boundary is reached and it rolls off into the history table, a rising count here just reflects legitimate billable load flowing through the tunnel in that direction, and tracking it separately per direction (forward vs. reverse) lets you tell whether a problem is one-sided rather than affecting the whole tunnel. For instance, over the in-progress 15-minute bin this counter might climb by roughly 5.1 MB of reverse-direction traffic — if the matching counter for the forward direction stays far lower (or far higher) than this one, that directional imbalance is itself the diagnostic clue, since a healthy bidirectional tunnel would normally carry fairly similar accepted volume both ways.