Users Guide
52
Stacking
Using the Dell Networking OS stacking feature, you can interconnect multiple switch units with stacking ports or front end user
ports. (The S4820T uses front end user ports for stacking.) The stack becomes manageable as a single switch through the stack
management unit.
The system accepts Unit ID numbers from 0 to 11 though the it supports stacking up to six units.
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
811