Using Ethernet Pause Frames For Flow Control - Dell Force10 Z9000 Configuration Manual

consecutive instances. Any deviation within that time sends Syslog and an alarm event generates. When the deviation clears,
another Syslog sends and a clear alarm event generates.
The link bundle utilization is calculated as the total bandwidth of all links divided by the total bytes-per-second of all links. If you
enable monitoring, the utilization calculation is performed when the utilization of the link-bundle (not a link within a bundle) exceeds
60%.
To enable and view link bundle monitoring, use the following commands.
• Enable link bundle monitoring.
ecmp-group
• View all LAG link bundles being monitored.
show running-config ecmp-group

Using Ethernet Pause Frames for Flow Control

Ethernet pause frames and threshold settings are supported on the Dell Networking OS.
Ethernet Pause Frames allow for a temporary stop in data transmission. A situation may arise where a sending device may transmit
data faster than a destination device can accept it. The destination sends a PAUSE frame back to the source, stopping the sender's
transmission for a period of time.
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.
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 reception of frames with destination address
equal to this multicast address.
The PAUSE frame is defined by IEEE 802.3x and uses MAC Control frames to carry the PAUSE commands. Ethernet pause frames
are supported on full duplex only.
If a port is over-subscribed, Ethernet Pause Frame flow control does not ensure no-loss behavior.
Restriction: Ethernet Pause Frame flow control is not supported if PFC is enabled on an interface.
Control how the system responds to and generates 802.3x pause frames on Ethernet interfaces. The default is rx off tx off.
INTERFACE mode. flowcontrol rx [off | on] tx [off | on]
Where:
rx on: Processes the received flow control frames on this port.
rx off: Ignores the received flow control frames on this port.
tx on: Sends control frames from this port to the connected device when a higher rate of traffic is received.
tx off: Flow control frames are not sent from this port to the connected device when a higher rate of traffic is received.
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, shutdown the interface using the shutdown command, enable the interface using the no
shutdown command, and use the show interface command to verify the changes.
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Interfaces