An Eth-Trunk uses 16 timeslots to send packets in a polling manner at each sending interval.
When the number of Eth-Trunk member interfaces is nth power of 2, traffic can evenly load balanced. For example, when an Eth-Trunk has 2, 4, or 8 member interfaces(divided by 16), the Eth-Trunk can obtain an integral value of timeslots and the load balancing is even. If the number of Eth-Trunk member interfaces is not nth power of 2 (for example, 3), one interface can send packets six times and the other two interfaces can send packets five times. In this case, the load balancing is uneven.
It is recommended that the number of Eth-Trunk member interfaces is nth power of 2 to achieve even load balancing.