Allied Telesis AlliedWare Plus GS980MX Series Installation Manual page 62

Chapter 2: Virtual Chassis Stacking
62
A stack trunk of multi-speed 5Gbps ports can have up to 8 ports on

the GS980MX/10HSm and GS980MX/18HSm switches, and up to
4 ports on the GS980MX/52PSm switch.
The multi-speed 5Gbps ports on the GS980MX/52PSm switch are

divided into the two groups: ports 41 to 44 and ports 45 to 48. The
ports of a trunk must be from the same group. The maximum
number of ports for a trunk is 4, for a maximum bandwidth of
20Gbps per switch.