设备堆叠的组件，除了设备之外，需要堆叠模块和堆叠线！
堆叠电缆是堆叠架构的必要条件。支持Cisco Catalyst 3850系列SW的堆叠电缆可用于9300模块化上行链路型号，使其向后兼容。根据基础架构的物理设置，可能需要不同的堆叠电缆。每个Cisco Catalyst SW最多支持两个用于数据堆叠的堆栈，电缆表1和2列出了Catalyst 9300型号的可用堆叠电缆。
Add or Replace a Member
Several factors must be considered when you implement a new stack or add a member to an established stack. Importantly, never connect a powered-on switch into a powered-on stack. Connect new member(s) while powered-down to avoid a stack-merge. These are other points to consider:
• Cisco IOS® XE version must match
• License level must match
• Operational mode (Install vs Bundle) must match
The auto-upgrade feature can be leveraged to resolve these conflict problems when you add a new switch. It is implemented with this command:
C9300-Stack#config t
Enter configuration commands, one per line.
