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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
78-14099-04
Chapter 6 Configuring Interfaces
Configuring Optional Interface Features
This example shows how to configure the MTU size on Gigabit Ethernet port 1/2:
Router# configure terminal
Router(config)# interface gigabitethernet 1/2
Router(config-if)# mtu 9216
Router(config-if)# end
This example shows how to verify the configuration:
Router# 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...>
Router#

Configuring the Global LAN Port MTU Size

To configure the global LAN port MTU size, perform this task:
Configuring IEEE 802.3Z Flow Control
Gigabit Ethernet and 10-Gigabit Ethernet ports on the Catalyst 6500 series switches use flow control to
stop the transmission of frames to the port for a specified time; other Ethernet ports use flow control to
respond to flow-control requests.
If a Gigabit Ethernet or 10-Gigabit Ethernet port receive buffer becomes full, the port transmits an
IEEE 802.3Z pause frame that requests remote ports to delay sending frames for a specified time. All
Ethernet ports (10 Gbps, 1 Gbps, 100 Mbps, and 10 Mbps) can receive and respond to IEEE 802.3Z
pause frames from other devices.
To configure flow control on an Ethernet port, perform this task:
Command Purpose
Step 1 Router(config)# system jumbomtu mtu_size Configures the global LAN port MTU size.
Router(config)# no system jumbomtu Reverts to the default global LAN port MTU size (9216
bytes).
Step 2 Router(config)# end Exits configuration mode.
Command Purpose
Step 1 Router(config)# interface type1 slot/port
1. type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet
Selects the port to configure.
Step 2 Router(config-if)# flowcontrol {receive | send}
{desired | off | on}
Configures a port to send or respond to pause frames.
Router(config-if)# no flowcontrol {receive |
send}
Reverts to the default flow control settings.
Step 3 Router# show interfaces [type1 slot/port]
flowcontrol
Displays the flow-control configuration for all ports.