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Enable Pause Frames
Ethernet Pause Frames flow control must be enabled on all ports on a chassis or a line card. If not, the
system may exhibit unpredictable behavior.
On the C-Series and S-Series systems, the flow-control sender and receiver must be on the same
port-pipe. Flow control is not supported across different port-pipes on the C-Series or S-Series system.
Note: On the C-Series and S-Series platforms, Ethernet Pause Frames TX should be enabled only after
consulting with the Dell Force10 Technical Assistance Center.
On 4-port 10G line cards: Changes in the flow-control values are not reflected automatically in the show
interface output for 10G interfaces. This issue results from the fact that 10G interfaces do not support
auto-negotiation per-se. On 1G interfaces, changing the flow control values causes an automatic interface flap,
after which PAUSE values are exchanged as part of the auto-negotiation process. As a workaround, apply the
new settings, execute shut followed by no shut on the interface, and then check the running-config of the port.
Command Syntax Command Mode Purpose
flowcontrol rx [off | on] tx [off | on] [threshold
{<1-2047> <1-2013> <1-2013>}]
INTERFACE Control how the system responds to and
generates 802.3x pause frames on 1 and 10Gig
line cards.
Defaults:
C-Series: rx off tx off
E-Series: rx on tx on
S-Series: rx off tx off
Parameters:
rx on: Enter the keywords rx on to process the received flow control frames
on this port.
rx off
: Enter the keywords rx off to ignore the received flow control frames
on this port.
tx on
: Enter the keywords tx on to send control frames from this port to the
connected device when a higher rate of traffic is received.
tx off
: Enter the keywords tx off so that flow control frames are not sent
from this port to the connected device when a higher rate of traffic is received.
threshold (C-Series and S-Series only): When tx on is configured,
the user can set the threshold values for:
Number of flow-control packet pointers: 1-2047 (default = 75)
Flow-control buffer threshold in KB: 1-2013 (default = 49KB)
Flow-control discard threshold in KB: 1-2013 (default= 75KB)
Pause control is triggered when either the flow control buffer threshold
or flow control packet pointer threshold is reached.