Users Guide
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Stacking
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 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
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 Ten GigabitEthernet Port 1 on Stack Unit 1, enter
interface tengigabitethernet 1/1 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 congure the front ports
on the device 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 congure:
• 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 conguration (which includes ACL, LACP, STP, SPAN, and so on.)
• Logs
The master switch maintains stack operation with minimal impact in the event of:
• Switch failure
• Inter-switch stacking link failure
• Switch insertion
• Switch removal
If the master switch goes o line, the standby replaces it as the new master and the switch with the next highest priority or MAC
address becomes standby.
Stacking
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