Users Guide

tx on Enter the keywords tx on to send control frames from this port to the connected device
when a higher rate of trac is received. This is the default value on the send side.
tx o Enter the keywords tx off so that ow control frames are not sent from this port to
the connected device when a higher rate of trac is received.
Defaults
• rx off
• tx off
Command Modes INTERFACE
Supported Modes Programmable-Mux (PMUX)
Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
9.4(0.0) Supported on the FN I/O Aggregator.
9.2(0.0) Introduced on the M I/O Aggregator.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
Usage Information
The globally assigned 48-bit Multicast address 01-80-C2-00-00-01 is used to send and receive pause frames. To
allow full-duplex ow control, stations implementing the pause operation instruct the MAC to enable the reception
of frames with a destination address equal to this multicast address.
The pause:
• Starts when either the packet pointer or the buer threshold is met (whichever is met rst). When the discard
threshold is met, packets are dropped.
• Ends when both the packet pointer and the buer threshold fall below 50% of the threshold settings.
The discard threshold denes when the interface starts dropping the packet on the interface. This may be
necessary when a connected device does not honor the ow control frame sent by the switch. The discard
threshold should be larger than the buer threshold so that the buer holds at least hold at least three packets.
Important Points to Remember
• Do not enable tx pause when buer carving is enabled. For information and assistance, consult Dell
Networking TAC.
• Asymmetric ow control (rx on tx off, or rx off tx on) setting for the interface port less than 100
Mb/s speed is not permitted. The following error is returned:
Can’t configure Asymmetric flowcontrol when speed <1G, config ignored
• The only conguration applicable to half duplex ports is rx off tx off. The following error is returned:
Cannot configure Asymmetric flowcontrol when speed <1G, config ignored>
• You cannot congure half duplex when the ow control conguration is on (default is rx on tx on). The
following error is returned: Cannot configure half duplex when flowcontrol is on,
config ignored
NOTE
: The ow control must be o (rx off tx off) before conguring the half duplex.
Example (partial)
Dell(conf-if-tengig-0/1)#show config
!
interface TenGigabitEthernet 0/1
no ip address
switchport
no negotiation auto
flowcontrol rx off tx on
192 Interfaces