This records the total elapsed seconds covered by this bin's path-layer counter set for the TDM circuit carried over this pseudowire. TTP is the denominator needed to turn ESP, SESP, UASP, or ASP on this same PW into a meaningful rate or percentage rather than a raw count with no time context -- and this specific object covers the current, still-open 15-minute interval -- a value that keeps climbing until the interval closes and rolls into history. For example, so far in the current, still-running 15-minute interval, this pseudowire might show this counter at 900 -- a concrete count the admin can trend against neighboring bins to judge whether the condition it reflects is worsening.