Reference Guide

912 | Stacking
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• Stack Group/Port Numbers
• High Availability on S-Series Stacks
• Important Points to Remember - S4810 and S4820T Stacking
• S-Series Stacking Configuration Tasks
• Troubleshoot an S-Series Stack
• Removing Units or Front End Ports from a Stack
S-Series Stacking Overview
An S-Series stack is analogous to an E-Series or C-Series system with redundant RPMs and multiple line
cards. FTOS elects a management (master) unit, a standby unit, and all other units are member units.
FTOS 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: The primary management unit, also called the master unit.
• Standby: The secondary management unit.
• Stack units: Also called stack members, these are the remaining units in the stack.
• Stack group: On the S4810 and S4820T, each set of 4 10G ports or each individual 40G port
correspond to a stack-group. The CLI is used to configure the front ports on the S4810 or S4820Tto be
stacking-ports.
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, etc.)
• Logs
The master switch maintains stack operation with minimal impact in the event of:
• Switch failure
• Inter-switch stacking link failure
• Switch insertion