Stack Split; The Original Master And Standby Switches Are In The Same Stack After The Original Stack Splits - Huawei S Series White Paper

S Series Switches
iStack Technology White Paper
Figure 2-11 Packet exchange during a stack merge
SwitchA
(Master)
SPDU A
Running state

2.8 Stack Split

Removing member switches with power on from a stable stack will cause the split of the stack.
Member switches act differently after the stack splits.
2.8.1 The Original Master and Standby Switches Are in the Same
Stack After the Original Stack Splits
As shown in Figure 2-12, after a stack splits into two new stacks, the original master and
standby switches in the stack belong to the same stack. The master switch recalculates the
stack topology and deletes the removed switches from the topology. The removed switches
restart after detecting that stack packets time out, and then select a new master switch.
After the original stack splits, the original master switch processes the NBR Lost packet of
SwitchD and deletes member switches (SwitchD and SwitchE). SwitchD and SwitchE restart
and then set up a new stack. Figure 2-13 shows the packet exchange process.
Issue 01 (2013-05-25)
SwitchB
(Standby)
SPDU A
Running state Running state
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SwitchC
(Slave)
Hello A
SPDU A
Two stacks are merged
The stack competition fails
The device restarts
After restarting, the device
is added as a member
device to the new stack
2 Technology Description
SwitchD
(Standby)
SPDU A
Two stacks are merged
The stack competition fails
The device restarts
After restarting, the device
is added as a member
device to the new stack
SwitchE
(Master)
21