The set of trunk ports to which frames destined for this multicast address should be forwarded. Each octet within the value of this object specifies a set or eight trunk ports, with the first octet specifiying trunk ports 1 through 8, the second octet specifying ports 9 through 16, etc. Within each octet the most significant bit represents the lowest numbered port, and the least significant bit represents the highest numbered port. Thus, each trunk port is represented by a single bit within the value of this object. If that bit has a value of '1' then that trunk port is included in the set of ports; the trunk port is not included if its bit has a value of '0'. The default value of this object is a string of ones of appropriate length.