This object represents the IP multicast address prefix length for this row. The value of this object represents the length in bits of docsBpiIpMulticastAddress for multicast address comparisons, using big-endian ordering. An IP multicast address matches this row if the (docsBpiIpMulticastPrefixLength) most significant bits of the IP multicast address and of the (docsBpiIpMulticastAddress) are identical. This object is similar in usage to an IP address mask. The value 0 corresponds to IP address mask 0.0.0.0, the value 1 corresponds to IP address mask 128.0.0.0, the value 8 corresponds to IP address mask 255.0.0.0, and the value 32 corresponds to IP address mask 255.255.255.255.