Administrator Guide

Configuring a Switch Stack
To configure and bring up a switch stack, follow these steps:
1. Connect the 40GbE ports on the base module of two Aggregators using 40G direct attach or QSFP
fibre cables.
2. Configure each Aggregator to operate in stacking mode.
3. Reload each Aggregator, one after the other in quick succession.
Stacking Prerequisites
Before you cable and configure a stack of MXL 10/40GbE switches, review the following prerequisites.
• All Aggregators in the stack must be powered up with the initial or startup configuration before you
attach the cables.
• All stacked Aggregators must run the same Dell Networking OS version. The minimum Dell
networking OS version required is 8.3.17.0. To check the version that a switch is running, use the show
version command. To download a Dell Networking OS version, go to http://support.dell.com.
• Stacking is supported only with other Aggregators. A maximum of six Aggregators are supported in a
single stack. You cannot stack the Aggregator with MXL 10/40GbE Switches or another type of switch.
• A maximum of four stack groups (40GbE ports) is supported on a stacked Aggregator.
• Interconnect the stack units by following the instructions in Cabling Stacked Switches.
• You cannot stack a Standalone IOA and a PMUX.
Master Selection Criteria
A Master is elected or re-elected based on the following considerations, in order:
1. The switch with the highest priority at boot time.
2. The switch with the highest MAC address at boot time.
3. A unit is selected as Standby by the administrator, and a fail over action is manually initiated or
occurs due to a Master unit failure.
No record of previous stack mastership is kept when a stack loses power. As it reboots, the election
process will once again determine the Master and Standby switches. As long as the priority has not
changed on any members, the stack will retain the same Master and Standby.
NOTE: Each stack members’ role (including the Master and Standby) can be defined by the user at
any time by setting the priority.
If the entire stack is powered OFF and ON again, the unit that was the Master before the reboot will
remain the Master after the stack resumes operation. However, when a stack is powered on, all members
are in sleep mode for 5 seconds while waiting on the previous Master to join the stack. If the previous
Master fails to join within 5 seconds, the remaining members (including the Standby) elect a new Master.
Configuring Priority and stack-group
Perform the following steps to configure the priorities and stack-groups for each of the switches.
1. Set the priorities for the stack-unit.
CONFIGURATION mode
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Stacking