摘要 |
A technique for designating output interfaces through which a data unit is transmitted in point-to-multipoint transmission is disclosed. An indicating word having a flag field, a group indicator field and a bitmask field is employed. The number of bits in the bitmask is less than the total number of output interfaces. The bitmask field has a plurality of bits for indicating output interfaces and the group indicator field designates an offset value such that the bitmask field and group indicator field together indicate particular individual output interfaces. The flag field serves as notification that additional such words are to be received in association with a given point-to-multipoint data unit transmission. |