Filter
Top Products
© 2012 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 15 of 17
The table shows the default priorities used by StackPower that can be overwritten by an administrator. As an
example, a power stack can assign priority 2 to a switch-A, priority 10 to high priority ports, and priority 20 to low
priority ports. Each switch in the stack will have a different priority set for the switch, high priority ports, and low
priority ports respectively. The priority levels are not repeated on any switch or port. That is switch-A with has
priority level 10 for its high priority ports and if load shedding is required, all other switches in the stack will have to
shed off their low priority ports (priority 19-27) and their high priority ports (priority 11-18) before switch-A has to
shed off PoE power on its high priority ports because it has the highest priority level (10) for high priority ports.
Figure 13. Load shed sequence
IOS has the capability to monitor administrator priority settings to make sure that a high priority port in Switch-A
cannot have a lower priority level than a low priority port on another switch in the stack.
As an administrator you can select any priority level for your switches and devices as long as you keep the
hierarchy of the switches, high priority ports, and low priority ports in such a way that a high priority port will not
shed off before a low priority port.
Best Practices
Cisco StackPower is an innovative technology that allows for a flexible and efficient use of the power resources in
a stack of switches; such an orchestration of hardware capabilities, resources, and features require us to follow
certain practices to insure proper and better use of this technology.
Recommendations:
1. Deploy power supplies in a balanced manner, that is, spread larger power supplies across all switches in the
stack or install larger power supplies on non-adjacent switches in the stack.
2. Also, fill in slot A of all switches in the stack before installing a power supply in slot B of any switch.