This counter tallies the total kilobytes that a policy map made pass-through, meaning that data bypassed optimization, since the policy became active. An administrator can use it alongside the pass-through connection counter to gauge how much data volume, not just connection count, is escaping optimization under a given policy. For example, a small number of pass-through connections that still account for a large share of pass-through bytes would suggest a few large flows are slipping past optimization under that policy.