Cisco Switch Cluster & Switch Stack

A switch cluster is a set of up to 16 connected, cluster-capable Catalyst switches that are managed as a single entity. The switches in the cluster use the switch clustering technology so that you can configure and troubleshoot a group of different Catalyst desktop switch platforms through a single IP address.

In a switch cluster, 1 switch must be the cluster command switch and up to 15 other switches can be cluster member switches. The total number of switches in a cluster cannot exceed 16 switches. The cluster command switch is the single point of access used to configure, manage, and monitor the cluster member switches. Cluster members can belong to only one cluster at a time.

A switch stack is a set of up to nine stacking-capable switches connected through their StackWise Plus or StackWise ports

Switch Cluster: When you have a large campus network with many switches, instead of

managing each switch using their IP, you can add them to the cluster and

manage it through the cluster. (Cluster is good from management perspective)

Switch Stack: When you have a switch closet and need more than 48 ports to connect

your clients, Stack is a good solution. Also, if you need to have redundant

links to a specific device (NIC teaming), stack is a good option as it

supports cross-stack etherchannel.

Basic Comparison of Switch Stacks and Switch Clusters 

Switch Stack	Switch Cluster
Made up of Catalyst 3750-E or Catalyst 3750-X switches only	Made up of cluster-capable switches, such as Catalyst 3750-E, Catalyst 3560-E, Catalyst 3750, and Catalyst 2950 switches
Stack members are connected through StackWise Plus ports	Cluster members are connected through LAN ports
Requires one stack master and supports up to eight otherstack members	Requires 1 cluster command switch and supports up to 15 othercluster member switches
Can be a cluster command switch or a cluster member switch	Cannot be a stack master or stack member
Stack master is the single point of complete management for all stack members in a particular switch stack	Cluster command switch is the single point of some management for all cluster members in a particular switch cluster
Back-up stack master is automatically determined in case the stack master fails	Standby cluster command switch must be pre-assigned in case the cluster command switch fails
Switch stack supports up to eight simultaneous stack master failures	Switch cluster supports only one cluster command switch failure at a time
Stack members (as a switch stack) behave and is presented as a single, unified system in the network	Cluster members are various, independent switches that are not managed as and do not behave as a unified system
Integrated management of stack members through a single configuration file	Cluster members have separate, individual configuration files
Stack- and interface-level configurations are stored on each stack member	Cluster configuration are stored on the cluster command switch and the standby cluster command switch
New stack members are automatically added to the switch stack	New cluster members must be manually added to the switch cluster