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Software Configuration Guide—Release 12.2(25)SG
OL-7659-02
Chapter4 Configuring Interfaces
Understanding Online Insertion and Removal
This example shows how to verify the configuration:
switch# show interface gigabitethernet 1/2
GigabitEthernet1/2 is administratively down, line protocol is down
Hardware is C6k 1000Mb 802.3, address is 0030.9629.9f88 (bia 0030.9629.9f88)
MTU 9216 bytes, BW 1000000 Kbit, DLY 10 usec,
<...Output Truncated...>
switch#

Interacting with the Baby Giants Feature

The baby giants feature, introduced in Cisco IOS Release 12.1(12c)EW, uses the global command
system mtu <size> to set the global baby giant MTU. This feature also allows certain interfaces to
support Ethernet payload size of up to 1552 bytes.
Both the system mtu command and the per-interface mtu command can operate on interfaces that can
support jumbo frames, but the per-interface mtu command takes precedence.
For example, before setting the per-interface MTU for interface gi1/1, you issue the
system mtu 1550 command to change the MTU for gi1/1 to 1550 bytes. Next, you issue the per-interface
mtu command to change the MTU for gi1/1 to 9198 bytes. N ow, if you change the baby giant MTU to
1540 bytes with the command system mtu 1540, the MTU for gi1/1 remains unchanged at 9198 bytes.
Understanding Online Insertion and Removal
The online insertion and removal (OIR) feature supported on the Catalyst 4500 se ries switch allows you
to remove and replace modules while the system is online. You can shut down the module before removal
and restart it after insertion without causing other software or interfaces to shut down.
You do not need to enter a command to notify the software that you are going to remove or install a
module. The system notifies the supervisor engine that a module has been removed or installed and scans
the system for a configuration change. The newly installed module is initialized, and each interface type
is verified against the system configuration; then the system runs diagnostics on the new int erface. There
is no disruption to normal operation during module insertion or removal.
If you remove a module and then replace it, or insert a different module of th e same type into the same
slot, no change to the system configuration is needed. An inte rface of a type that has been configured
previously will be brought online immediately. If you remove a module and insert a module of a different
type, the interface(s) on that module will be administratively up with the default configuration for that
module.
Monitoring and Maintaining the Interface
The following sections describe how to monitor and maintain the interfaces:
•Monitoring Interface and Controller Status, page 4-14
•Clearing and Resetting the Interface, page 4-14
•Shutting Down and Restarting an Interface, page 4-15
•Configuring Interface Link Status and Trunk Status Events, page 4-15