Users Guide

Command History
Version Description
9.6(0.0) Supported on the FN 2210S Aggregator and M I/O Aggregator.
flowcontrol
Controls how the system responds to and generates 802.3x pause frames on 10G and 40Gig stack units.
Syntax
flowcontrol rx {off | on} tx {off | on} pause-threshold value
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.
pause-threshold Enter the buffer threshold limit for generating PAUSE frames.
Defaults
• rx off
• tx off
Command Modes INTERFACE
Supported Modes Programmable-Mux (PMUX)
Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
9.4(0.0) Supported on the FN I/O Aggregator.
9.2(0.0) Introduced on the M I/O Aggregator.
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.
196 Interfaces