Users Guide

ManualsBrandsDell ManualsAccess PlatformsPowerSwitch S4820T

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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.

To view failover details, use the show redundancy command.

MAC Addressing on S-Series Stacks

The S-Series has three MAC addresses: the chassis MAC, interface MAC, and null interface MAC.

All interfaces in the stack use the interface MAC address of the management unit, and the chassis MAC for the stack is the master’s

chassis MAC. 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 manager.

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.

A standalone is added to a stack. The standalone and the master unit have the same priority, but the standalone has a lower MAC

address, so the standalone reboots. In the second example, a standalone is added to a stack. The standalone has a higher priority

than the stack, so the stack (excluding the new unit) reloads.

Example of Adding a Standalone with a Lower MAC Address to a Stack

----------STANDALONE BEFORE CONNECTION---------------

Standalone#show system brief

Stack MAC : 00:01:e8:d5:ef:81

-- Stack Info --

Unit UnitType Status ReqTyp CurTyp Version Ports

------------------------------------------------------

0 Management online

S4820T

S4820T 7.8.1.0 52

1 Member not present

2 Member not present

3 Member not present

4 Member not present

5 Member not present

6 Member not present

[output omitted]

Standalone#show system | grep priority

Master priority : 0

-----------STACK BEFORE CONNECTION----------------

Stack#show system brief

Stack MAC : 00:01:e8:d5:f9:6f

-- Stack Info --

Unit UnitType Status ReqTyp CurTyp Version Ports

---------------------------------------------------

0 Standby online