Service Manual

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Stacking
Using the Dell Networking OS stacking feature, you can interconnect multiple switch units with stacking
ports or front end user ports. (The S4048-ON 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 1 to 6 and 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.
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:
• Switch failure
• Inter-switch stacking link failure
• Switch insertion
• Switch removal
If the master switch goes off line, the standby replaces it as the new master and the switch with the next
highest priority or MAC address becomes standby.
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Stacking