The pause:
• Starts when
either
the packet pointer or the buffer threshold is met (whichever
is met first). When the discard threshold is met, packets are dropped.
• Ends when
both
the packet pointer and the buffer threshold fall below 50% of
the threshold settings.
The
discard threshold
defines when the interface starts dropping the packet on the
interface. This may be necessary when a connected device does not honor the
flow control frame sent by the switch. The discard threshold should be larger than
the
buffer threshold
so that the buffer holds at least hold at least three packets.
Changes in the flow-control values may not be reflected automatically in the
show
interface
output. As a workaround, apply the new settings, execute
shut
then
no shut
on the interface, then check the running-config of the port using the
show interface
command.
Important Points to Remember
• Do not enable
tx pause
when buffer carving is enabled. For information and
assistance, consult Dell Networking TAC.
• Asymmetric flow 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 configuration applicable to half duplex ports is
rx off tx off
. The
following error is returned:
Can’t configure flowcontrol when half duplex is configure,
config ignored
• Half duplex cannot be configured when the flow control configuration is on
(default is
rx on tx on
). The following error is returned:
Can’t configure half duplex when flowcontrol is on, config
ignored
NOTE: The flow control must be off (
rx off tx off
) before configuring the
half duplex.
NOTE: If you use the
disable rx flow control
command, Dell
Networking recommends rebooting the system.
Example
Dell(conf-if-te-0/1)#show config
!
interface TengigabitEthernet 0/1
no ip address
switchport
no negotiation auto
flowcontrol rx off tx on
no shutdown
...
Related
Commands
show running-config
— displays the flow configuration parameters (non-default
values only).
Interfaces
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