Users Guide

Control how the system responds to and generates 802.3x pause frames on Ethernet interfaces. The default is rx o tx o. INTERFACE
mode. flowcontrol rx [off | on] tx [off | on]| [monitor session-ID]
Where:
rx on: Processes the received ow control frames on this port.
rx off: Ignores the received ow control frames on this port.
tx on: Sends control frames from this port to the connected device when a higher rate of trac is received.
tx off: Flow control frames are not sent from this port to the connected device when a higher rate of trac is received.
monitor session-ID: Enables mirror ow control frames on this port.
Changes in the ow-control values may not be reected automatically in the show interface output. To display the change, apply the
new ow-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.
Enabling Pause Frames
Enable Ethernet pause frames ow control on all ports on a chassis or a line card. If not, the system may exhibit unpredictable behavior.
NOTE
: Changes in the ow-control values may not be reected automatically in the show interface output. As a workaround,
apply the new settings, execute shut then no shut on the interface, and then check the running-cong of the port.
NOTE: If you disable rx flow control, Dell Networking recommends rebooting the system.
The ow control sender and receiver must be on the same port-pipe. Flow control is not supported across dierent port-pipes.
To enable pause frames, use the following command.
• Control how the system responds to and generates 802.3x pause frames on the Ethernet ports.
INTERFACE mode
flowcontrol {rx [off | on] tx [off | on] }
• rx on: enter the keywords rx on to process the received ow control frames on this port.
• rx off: enter the keywords rx off to ignore the received ow 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 trac is
received.
• tx off: enter the keywords tx off so that ow control frames are not sent from this port to the connected device when a
higher rate of trac is received.
Congure the MTU Size on an Interface
If a packet includes a Layer 2 header, the dierence in bytes between the link MTU and IP MTU must be enough to include the Layer 2
header.
For example, for VLAN packets, if the IP MTU is 1400, the Link MTU must be no less than 1422:
1400-byte IP MTU + 22-byte VLAN Tag = 1422-byte link MTU
The following table lists the various Layer 2 overheads found in Dell Networking OS and the number of bytes.
The MTU range is from 592 to 9216, with a default of 9216. IP MTU automatically congures.
Interfaces
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