452 | Interfacesw w w . d e l l . c o m | s u p p o r t . d e l l . c o m Enable Pause FramesEthernet Pause Frames flow control must be enabled on all ports on a chassis or a line card. If not, thesystem may exhibit unpredictable behavior.On the C-Series and S-Series systems, the flow-control sender and receiver must be on the sameport-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 afterconsulting 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 showinterface output for 10G interfaces. This issue results from the fact that 10G interfaces do not supportauto-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 thenew settings, execute shut followed by no shut on the interface, and then check the running-config of the port.Command Syntax Command Mode Purposeflowcontrol rx [off | on] tx [off | on] [threshold{<1-2047> <1-2013> <1-2013>}]INTERFACE Control how the system responds to andgenerates 802.3x pause frames on 1 and 10Gigline cards.Defaults:C-Series: rx off tx offE-Series: rx on tx onS-Series: rx off tx offParameters:rx on: Enter the keywords rx on to process the received flow control frameson this port.rx off: Enter the keywords rx off to ignore the received flow control frameson this port.tx on: Enter the keywords tx on to send control frames from this port to theconnected device when a higher rate of traffic is received.tx off: Enter the keywords tx off so that flow control frames are not sentfrom 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 thresholdor flow control packet pointer threshold is reached.
