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144 C
HAPTER
7: P
HYSICAL
P
ORT
N
UMBERING
Effects of Replacing
Modules
When you remove a module and replace it with another module, a
number of changes can occur, depending on the replacement module.
Replacing Modules of
the Same Type
If you remove a module and replace it with a module of the same type
(model number), the following occurs:
■
Port numbering is not affected — you can exchange modules without
affecting the port numbers.
■
The system remembers ports that were members of trunks and VLAN.
When you insert another module into the slot, the ports are added
back into the trunks and VLANs.
Example:
If you have a 20-port Fast Ethernet module with ports 1 and 2 assigned to
a VLAN, and then replace it with a new 20-port Fast Ethernet module, the
new module takes on the configuration of the previous module.
Replacing Modules of
Different Types
More complicated changes occur when you replace modules of different
types (different model numbers).
Swapping a 20-port Fast Ethernet Layer 2 Switching Module with a
12-port Fast Ethernet Multilayer Switching module has the following
effects:
■
Port numbering is reduced to 10 ports.
■
The new module configures to its default VLAN settings. The system
does not remember which ports were part of a previous VLAN. You
must redefine any new VLANs.
■
The ports from any previous trunk configurations are dropped. You
must redefine any new trunks.
Example:
If you replace a Fast Ethernet Switching Module in slot 1 (that has a
trunk on ports 5 and 6) with an Fast Ethernet Multilayer Switching
Module, the new FX ports 5 and 6 do
not
become part of the trunk.
For more information about trunking, see Chapter 12. For information
about VLANs, see Chapter 14.