Physical port cannot ioin Eth-Trunk and its reasons.
1. It does not support mixed plugging. GE cannot join Eth-Trunk including FE. FE cannot join Eth-Trunk including GE.
2. The physical interface is raw configuration.
3. The numbers of Eth-Trunk reach 16.
4. The physical interface state is not UP.
5. It does not support cross-board bundling.
6. Illegal MAC address such as MAC address 0xFFFFFFFFFFFF.
Bind many Etherne ports as one logical port, namely, Eth-Trunk interface.