Reference Guide

flowcontrol
Set how the system responds to and generates 802.3x pause frames on Ethernet interfaces.
S5000
Syntax
flowcontrol rx {off | on} tx {off | on}
Parameters
rx on Enter the keywords rx on to process the received flow
control frames on this port. This is the default value for the
receive side.
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. This is the default value on the send side.
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.
Defaults rx off tx off
Command
Modes
INTERFACE
Command
History
Version 9.0(1.3) Introduced on the S5000.
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 flow control, stations implementing
the pause operation instruct the MAC to enable the reception of frames with a
destination address equal to this multicast address.
An Ethernet interface starts to send pause frames to a sending device when the
transmission rate of ingress traffic exceeds the egress port speed. The interface
stops sending pause frames when the ingress rate falls to less than or equal to
egress port speed.
Changes in the flow-control values may not be reflected automatically in show
interface output. To display the change, apply the new flow-control setting,
perform a
shutdown followed by a no shutdown on the interface, and then check
re-display the show interface output for the port.
Important Points to Remember
• On the S5000, Ethernet Pause Frame flow control is not supported if PFC is
enabled on one or more interfaces.
• On the S5000, threshold settings on the transmission pause (tx on) are not
supported for Ethernet Pause Frame flow control.
• Do not enable tx pause when buffer carving is enabled. For information and
assistance, contact Dell Networking TAC.
520
Interfaces