Dell FCX624-E Laptop User Manual


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38 PowerConnect B-Series FCX Configuration Guide
53-1002266-01
Configuring basic port parameters
2
Disabling or re-enabling a port
A port can be made inactive (disable) or active (enable) by selecting the appropriate status option.
The default value for a port is enabled.
To disable port 8 of a Dell PowerConnect device, enter the following.
PowerConnect(config)# interface ethernet 8
PowerConnect(config-if-e1000-8)# disable
You also can disable or re-enable a virtual interface. To do so, enter commands such as the
following.
PowerConnect(config)# interface ve v1
PowerConnect(config-vif-1)# disable
Syntax: disable
To re-enable a virtual interface, enter the enable command at the Interface configuration level. For
example, to re-enable virtual interface v1, enter the following command.
PowerConnect(config-vif-1)# enable
Syntax: enable
Configuring flow control
Flow control (802.3x) is a QoS mechanism created to manage the flow of data between two
full-duplex Ethernet devices. Specifically, a device that is oversubscribed (is receiving more traffic
than it can handle) sends an 802.3x PAUSE frame to its link partner to temporarily reduce the
amount of data the link partner is transmitting. Without flow control, buffers would overflow,
packets would be dropped, and data retransmission would be required.
All PowerConnect devices support asymmetric flow control, meaning they can receive PAUSE
frames but cannot transmit them. In addition, FCX devices also support symmetric flow control,
meaning they can both receive and transmit 802.3x PAUSE frames. For details about symmetric
flow control, refer to “Configuring symmetric flow control on PowerConnect B-Series FCX devices”
on page 40.
Configuration notes
Auto-negotiation of flow control is not supported on 10 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 ports, the show interface <port> display shows Flow Control is enabled or Flow
Control is disabled, depending on the configuration.
When flow-control is enabled, the hardware can only advertise PAUSE frames. It does not
advertise Asym.