User Manual

Stacking
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M4200 and M4300 Series ProSAFE Managed Switches Web Management User Manual
M4300 Series Switch Stacking Overview
A stackable switch is a switch that is fully functional operating as a stand-alone unit but can
also be set-up to operate together with up to seven other switches. This group of switches
shows the characteristics of a single switch while having the port capacity of the sum of the
combined switches.
One of the switches in the stack controls the operation of the stack. This switch is called the
stack master. The remaining switches in the stack are stack members. The stack members
use stacking technology to behave and work together as a unified system. Layer 2 and higher
protocols present the entire switch stack as a single entity to the network.
The stack master is the single point of stack-wide management. From the stack master, you
configure the following:
• System-level (global) features that apply to all stack members
• Interface-level features for all interfaces on any stack member
A switch stack is identified in the network by its network IP address. The network IP address
is assigned according to the MAC address of the stack master. Every stack member is
uniquely identified by its own stack member number, which is from 1 to 6. The stack master
can be any number within that range.
Stacking supports the following:
• Up to eight switches per stack
• Single IP address management through a web browser, the CLI, or SNMP.
• Master-slave configuration:
• The master retains configuration for entire stack.
• Automatic detection of new members, with synchronization of firmware (upgrade or
downgrade as needed).
• Configuration updates across the stack through a single operation.
• Automatic master failover. Fully resilient stack with chain and ring topology.
• Hot swapping (insertion and removal) of stack members.
Firmware Synchronization and Upgrade
All stack members must run the same software version to ensure compatibility within the
stack. By default, if a unit is added to the stack and its software version is not the same as the
stack master, that unit is not allowed to join the stack. You can enable the Stack Firmware
Auto Upgrade feature, which automatically synchronizes the firmware version on the new unit
with the version running on the stack master. The synchronization operation might result in
either upgrade or downgrade of firmware on the mismatched stack member.
Upgrading the firmware on a stack of switches is the same as upgrading the firmware on a
single switch. After you download a new image by using the File Download page or SCC, the
downloaded image is distributed to all the connected units of the stack.