Service Manual

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
S3048-ON
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
S3048-ON
1 Management online
S3048-ON
2 Member not present
3 Member not present
4 Member not present
5 Member not present
6 Member not present
7 Member not present
[output omitted]
Stack#show system stack-unit 1 | grep priority
Master priority : 0
Stack#show system stack-unit 2 | grep priority
Master priority : 0
Example of Adding a Standalone with a Lower MAC Address and Equal Priority to a Stack
---------------STANDALONE AFTER CONNECTION-----------------
Standalone#%STKUNIT0-M:CP %POLLMGR-2-ALT_STACK_UNIT_STATE: Alternate Stack-unit is present
00:20:20: %STKUNIT0-M:CP %CHMGR-5-STACKUNITDETECTED: Stack unit 1 present
00:20:22: %STKUNIT0-M:CP %CHMGR-5-STACKUNITDETECTED: Stack unit 2 present
Going for reboot. Reason is Stack merge
[bootup messages omitted]
---------------STACK AFTER CONNECTION---------------------
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