Administrator Guide

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.
negotiate (Optional) Enter the keyword negotiate to enable the
pause-negotiation with the egress port of the peer device. If
the negotiate command is not used, pause-negotiation is
disabled. 40 gigabit Ethernet interfaces do not support
pause-negotiation.
Defaults
• rx off
• tx off
Command
Modes
INTERFACE
Command
History
Version 9.6.0.0 Added support for the negotiate feature on the M I/O
Aggregator.
Version 9.2(0.0) Introduced on the M I/O Aggregator. This command is
supported in Programmable-Mux (PMUX) mode only.
Version 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 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.
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.
On 4–port 10G stack units: Changes in the flow-control values may not be
reflected automatically in the show interface output for 10G interfaces. This is
because 10G interfaces do not support auto-negotiation.
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Interfaces