It is recommended that stack member switches be connected in MPU connection mode shown in Figure 3-1. Stack connection links including the following ones:

• Management link: forwards stack management and maintenance packets and connects system interconnect ports (SIPs) on MPUs. Each MPU has two SIP ports, which must be connected in full-mesh connection mode as shown in Figure 3-1.
• Forwarding link: forwards service data packets between stack member switches and connects to service ports on LPUs. To ensure high reliability, it is recommended that each member switch use two or more LPUs to set up a stack.
• DAD link: forwards DAD packets and connects to idle service ports on LPUs. DAD in direct mode through service ports is recommended.

Figure 3-1 Stack connection mode

Stack setup just requires ordinary service cables instead of dedicated stack cables.

• SIP ports on MPUs are GE optical/electrical multiplexing ports. These ports can be connected using network cables or GE optical modules+LC optical fibers.
• All types of ports except GE ports on LPUs can be used for stack connections, such as 10GE, 40GE, and 100GE ports.

  Optical ports can be connected using high-speed cables, AOC cables, or optical modules+fibers. Electrical ports can be connected using Category 6, Category 6A, or Category 7 cables.

• DAD can be performed on any type of port, and cables can be selected according to the port type.

For details about stack ports and cables, see What Ports Can Be Used to Set Up a Stack, What Cables Can Be Used to Set Up a Stack and What Cables Can Be Used to Set Up a Stack.