9-13
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 9 Configuring Interfaces
Configuring Optional Interface Features
•
For VLAN interfaces and Layer 3 Ethernet ports, supported MTU values are from 64 to 9216 bytes.
•
For Layer 2 Ethernet ports, you can configure only the global egress LAN port MTU size (see the
“Configuring the Global Egress LAN Port MTU Size” section on page 9-13
).
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 Egress LAN Port MTU Size
To configure the global egress LAN port MTU size, perform this task:
Configuring IEEE 802.3x Flow Control
Gigabit Ethernet and 10-Gigabit Ethernet ports on the Cisco 7600 series routers 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 802.3x 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 802.3x
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 egress LAN port MTU size.
Router(config)#
no system jumbomtu
Reverts to the default global egress LAN port MTU size
(9216 bytes).
Step 2
Router(config)#
end
Exits configuration mode.
Command
Purpose
Step 1
Router(config)#
interface
type
1
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
[
type
1
slot/port
]
flowcontrol
Displays the flow-control configuration for all ports.
