5-2
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 5 Managing Switch Stacks
Understanding Switch Stacks
Understanding Switch Stacks
A switch stack is a set of up to nine stacking-capable switches connected through their StackWise Plus
or StackWise ports. You can connect only one switch type in a stack, or you can connect a mix of
Catalyst 3750-X, Catalyst 3750-E, and Catalyst 3750 switches in the stack. Catalyst 3750-X and
Catalyst 3750-E stack members have StackWise Plus ports, and Catalyst 3750 members have StackWise
ports. The stack can have one of these configurations:
• Homogeneous stack—A Catalyst 3750-E-only stack with only Catalyst 3750-E switches as stack
members or a Catalyst 3750-X-only stack with only Catalyst 3750-X switches as stack members.
• Mixed stack
Note Mixed stacks are not supported with switches running the LAN base feature set.
–
A mixed hardware stack with a mixture of Catalyst 3750-X, Catalyst 3750-E, and 3750 switches
as stack members.
For example, a stack with Catalyst 3750-X and 3750 switches supporting the IP services
features.
–
A mixed software stack with only Catalyst 3750-X, only Catalyst 3750-E, or only Catalyst 3750
switches supporting different features as stack members.
For example, a Catalyst 3750-X-only stack with some members running the IP base feature set,
other members running the IP services feature set, and the remaining members running the IP
services feature set.
–
A mixed ha rd ware and s oftware s tack with Catalyst 3750-X, Catalyst 3750-E, and
Catalyst 3750 switches supporting different features as stack members.
For example, a stack with the Catalyst 3750-X members running the IP services feature set and
the Catalyst 3750 members running the IP services software image.
For information about Catalyst 3750 switches, see the “Managing Switch Stacks” chapter in the
Catalyst 3750 Switch Software Configuration Guide.
One of the switches controls the operation of the stack and is called the stack master. The stack master
and the other switches in the stack are all stack members. The Catalyst 3750-E stack members use the
Cisco StackWise Plus technology to work together as a unified system. Layer 2 and Layer 3 protocols
present the entire switch stack as a single entity to the network.
Note Switch stacks running the LAN base feature set do not support Layer 3 features.
The stack master is the single point of stack-wide management. From the stack master, you configure:
• System-level (global) features that apply to all stack members
• Interface-level features for each stack member
A switch stack is identified in the network by its bridge ID and, if it is operating as a Layer 3 device, its
router MAC address. The bridge ID and router MAC address are determined by the MAC address of the
stack master. Every stack member is identified by its own stack member number.
All stack members are eligible to be stack masters. If the stack master becomes unavailable, the
remaining stack members elect a new stack master from among themselves. The switch with the highest
stack member priority value becomes the new stack master.