Reference Guide
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Stacking
Stacking is supported on the S4820T platform.
Stacking is supported on the S4820T platform with the Dell Networking OS version 8.3.19.0 and newer.
NOTE: The S4820T commands accept Unit ID numbers 0-11, though the S4820T supports stacking
up to three units only with Dell Networking OS version 8.3.19.0 and version 8.3.10.2. The S4820T
supports stacking up to six units with Dell Networking OS version 8.3.19.0.
Using the Dell Networking OS stacking feature, you can interconnect multiple S-Series switch units with
dedicated stacking ports or front end user ports. (The S50, S55, and S60 use dedicated stacking ports; the
S4820T uses front end user ports for stacking.) The stack becomes manageable as a single switch
through the stack management unit.
S-Series Stacking Overview
An S-Series stack has redundant RPMs and multiple line cards. Dell Networking OS elects a management
(master) unit, a standby unit, and all other units are member units.
Dell Networking OS presents all of the units like line cards; for example, to access GigabitEthernet Port 1
on Stack Unit 0, enter interface gigabitethernet 0/1 from CONFIGURATION mode.
Stack Management Roles
The stack elects the management units for the stack management.
• Stack master — primary management unit, also called the master unit.
• Standby — secondary management unit.
• Stack units — the remaining units in the stack, also called stack members. The system supports up to
six stack units.
• Stack group — Each set of four 10G ports or each individual 40G port correspond to a stack-group.
To configure the front ports on the S4820T to be stacking-ports, use the CLI.
The master holds the control plane and the other units maintain a local copy of the forwarding databases.
From the stack master you can configure:
• System-level features that apply to all stack members.
• Interface-level features for each stack member.
The master synchronizes the following information with the standby unit:
• Stack unit topology
• Stack running configuration (which includes ACL, LACP, STP, SPAN, and so on.)
• Logs
The master switch maintains stack operation with minimal impact in the event of:
Stacking
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