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Use the following command to congure a virtual IP: Dell(conf)#virtual-ip {ip-address | ipv6–address | dhcp}
Failover Roles
If the stack master fails (for example, is powered o), it is removed from the stack topology.
The standby unit detects the loss of peering communication and takes ownership of the stack management, switching from the standby
role to the master role. The distributed forwarding tables are retained during the failover, as is the stack MAC address. The lack of a
standby unit triggers an election within the remaining units for a standby role.
After the former master switch recovers, despite having a higher priority or MAC address, it does not recover its master role but instead
takes the next available role.
MAC Addressing
All port interfaces in the stack use the MAC address of the management interface on the master switch. The MAC address of the chassis
in which you use the master switch as the stack MAC address.
The stack continues to use the master’s chassis MAC address even after a failover. The MAC address is not refreshed until the stack is
reloaded and a dierent unit becomes the stack master.
NOTE: If the removed management unit is brought up as a standalone unit or as part of a dierent stack, there is a possibility of
MAC address collisions. If you add a standalone unit, which has the same priority as the master stack unit, the standalone unit
joins the stack as a member unit.
Stacking LAG
When multiple links are used between stack units, Dell Networking OS automatically bundles them in a stacking LAG to provide aggregated
throughput and redundancy.
The stacking LAG is established automatically and transparently by Dell Networking OS (without user conguration) after peering is
detected and behaves as follows:
• The stacking LAG dynamically aggregates; it can lose link members or gain new links.
• Shortest path selection inside the stack: If multiple paths exist between two units in the stack, the shortest path is used.
High Availability on S5000 Stacks
An S5000 stack has a master and standby management unit that provide redundancy in a similar way to redundant route processor
modules (RPMs).
As shown in the following example, the show redundancy command displays the status and conguration of redundancy in the stack.
The master unit synchronizes the running conguration and protocol states so that the system fails over in the event of a hardware or
software fault on the master unit. In such an event, or when the master unit is removed, the standby unit becomes the stack manager and
Dell Networking OS elects a new standby unit. Dell Networking OS resets the failed master unit: after online, it becomes a member unit; the
remaining members remain online.
Example of S5000 Stack Manager Redundancy
Stack#show redundancy
-- Stack-unit Status --
----------------------------------------
Mgmt ID: 0
Stack-unit ID: 1
Stack-unit Redundancy Role: Primary
902
Stacking