Flow control configuration notes
• Auto-negotiation of flow control is not supported on 10 Gbps and 40 Gbps ports, fiber ports, and
copper or fiber combination ports.
• When any of the flow control commands are applied to a port that is up, the port will be disabled and
re-enabled.
• For 10 Gbps and 40 Gbps ports, the
show interface
command with the appropriate parameters
shows whether Flow Control is enabled or disabled, depending on the configuration.
• When flow-control is enabled, the hardware can only advertise PAUSE frames. It does not advertise
Asym.
• On ICX 7750 devices the default packet-forwarding method is cut-through, in which port flow control
(IEEE 802.3x) is not supported but priority-based flow control (PFC) is supported. You can configure
the
store-and- forward
command in global configuration mode to enable the store-and-forward
method for packet-forwarding.
NOTE
You must save the configuration and reload for the change to take effect. See the description of the
store-and-forward
command in the
FastIron Command Reference
for more information.
Disabling or re-enabling flow control
You can configure the Brocade device to operate with or without flow control. Flow control is enabled by
default globally and on all full-duplex ports. You can disable and re-enable flow control at the Global
CONFIG level for all ports. When flow control is enabled globally, you can disable and re-enable it on
individual ports.
To disable flow control, enter the
no flow-control
command.
device(config)# no flow-control
To turn the feature back on, enter the
flow-control
command.
device(config)# flow-control
Syntax:
[no] flow-control
NOTE
For optimal link operation, link ports on devices that do not support 803.3u must be configured with like
parameters, such as speed (10,100,1000), duplex (half, full), MDI/MDIX, and Flow Control.
Negotiation and advertisement of flow control
By default, when flow control is enabled globally and auto-negotiation is ON, flow control is enabled and
advertised on 10/100/1000M ports. If auto-negotiation is OFF or if the port speed was configured
manually, then flow control is not negotiated with or advertised to the peer. For details about auto-
negotiation, refer to
Port speed and duplex mode modification
on page 58.
To disable flow control capability on a port, enter the following commands.
device(config)
# interface ethernet 0/1/21
device(config-if-e1000-0/1/21)# no flow-control
Flow control configuration notes
FastIron Ethernet Switch Administration Guide
65
53-1003625-01