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About the Nortel Ethernet Routing Switch 4500 Series
•
If the administrator adds a new unit with a different hardware
configuration, the configuration of this unit is used.
•
If the administrator adds a new unit with the same hardware
configuration, the previous configuration of the new unit is lost. The
configuration is overwritten with the restored configuration from the
stack.
•
You can enable or disable this feature at any time using the CLI. The
default mode is ENABLE.
•
Customer log messages are provided.
Note: After booting a stack, use the CLI command
show stack
auto-unit-replacement
from a unit console to find out if that unit
is ready for replacement.
AUR function
The CFG mirror image is a duplicate CFG image (stored in the flash drive)
of a unit in a stack. The mirror image does not reside in the same unit
with the CFG image. The unit that contains the CFG image is called the
Associated Unit (AU) of the CFG mirror image. The MAC Address of the AU
is called the Associated Mac Address (AMA) of the CFG mirror image.
An active CFG Mirror Image is a CFG mirror image that has its AU in the
stack. An INACTIVE CFG Mirror Image is a CFG mirror image for which
the associated AU is removed from the stack. When a CFG mirror image
becomes INACTIVE, the INACTIVE CFG mirror image is copied to another
unit.
The stack always keeps two copies of an INACTIVE CFG mirror image in
the stack in case one unit is removed—the other unit can still provide the
backup INACTIVE CFG mirror image.
CFG mirror image process
The CFG mirror image process is triggered by specific events.
Power Cycle
After a power cycle, all the CFG images in a stack are
mirrored.
"CFG mirror process in stack" (page 123)
illustrates the CFG mirror images
in a three-unit stack after the stack is powered on. Unit 1 is the Based Unit
(BU) and all other units are Non-Based Units (NBU).
•
Unit 1 (BU) contains mirror images for unit 2 (CFG 2) and unit 3 (CFG3).
•
Unit 2 (NBU), is the TEMP-BU. It contains a mirror image of unit 1
(CFG1), in case the BU (unit 1) is removed from the stack.
•
All three mirror images (CFG 1, CFG 2, and CFG 3) are active.
Nortel Ethernet Routing Switch 4500 Series
Overview — System Configuration
NN47205-500
02.01
Standard
5.0
23 February 2007
Copyright © 2007, Nortel Networks
Nortel Networks Confidential
.