This object identifies ports that connect to child subtree of the multicast tree rooted at a3ComDvmrpRouteSource. Each octet, except the first one which contains a value specified length of this object, contains a bit map of 8 ports. The first (should say the second) octet specifies ports from 1 to 8, the next octet specifies ports 9 to 16, ... etc. The most significant bit in each octet represents the lowest port, the least significant bit represents the highest port among those 8 ports. If the bit is set then the corresponding port connects to a child subtree, otherwise the corresponding port does not connect to a child subtree. The tunnel ports does not include in this object, it is specified in next, a3ComDvmrpRouteChildTunnel object.