This attribute indicates the number of contiguous VPIs supported in
the optional Programmable VCC Space.
If numNonZeroVpisForVccs is 0 the Programmable VCC Space
does not exist. If numNonZeroVpisForVccs is greater than 0 the
Programmable VCC Space exists and covers the VPI values ranging
from firstNonZeroVpiForVccs to (firstNonZeroVpiForVccs +
numNonZeroVpisForVccs - 1). For Apc-based cards, the maximum
value of this attribute is 255 for UNI applications and 4095 for NNI
applications. For CQC-based cards, the maximum value is 255.
To override the system default, see the AtmIf ConnMap Ov attribute
numNonZeroVpisForVccs.