The CLK1 and CLK2 ports on the MPU correspond to the BITS0 and BITS1 ports on the clock card. BITS ports are connected to BITS devices or connected to BITS ports of other products to synchronize the time and clock.
For most S series fixed switches, the ports that are not configured as stack port can still run services. For example, when two rear SFP ports on an S5700-52P-LI switch are configured as stack ports, the other two rear SFP ports can forward service data. However, on the S6700EI and S6720EI, every four ports are added to one group. A group of ports must function as stack ports or service ports together. That is, when one port is configured as a stack port, the other three ports in the same group will automatically be configured as stack ports but cannot function as service ports.
