Users Guide

When a port receives traffic at a higher rate than it can process, the frames are stored in the port buffer. As a
result, buffer usage increases. When the buffer usage reaches the value specified in the “pause-threshold”
argument, the port sends PAUSE frame to the connected link partner to stop sending the traffic. Eventually this
reduces the buffer usage. When the buffer usage drops by the value specified in the “resume-threshold”, the port
again sends a PAUSE frame with 0 as wait-time. This results in resume of the paused traffic flow.
Important Points to Remember
• Do not enable tx pause when buffer carving is enabled. For information and assistance, consult Dell
Networking TAC.
• Speeds less than one Gig cannot be configured when the asymmetric flow control configuration is on. The
following error is returned:
Can’t configure speed <1G when Asymmetric flowcontrol is on, config ignored
• Dell Networking OS only supports rx on tx on and rx off tx off for speeds less than one Gig
(Symmetric).
NOTE: If you use the disable rx flow control command, Dell Networking recommends
rebooting the system.
NOTE: Dell Networking OS does not support mirroring of tx pause frames.
Example
Dell(conf-if-Gi-1/1)# show config
!
interface GigabitEthernet 1/1
no ip address
switchport
no negotiation auto
flowcontrol rx off tx on
no shutdown
...
Example (Values)
This Example shows how Dell Networking OS negotiates the flow control values between two Dell Networking
chassis connected back-to-back using 1G copper ports.
Configured
LocRxConf LocTxConf RemoteRxConf RemoteTxConf
off off off off
off on
on off
on on
off on off off
off on
on off
on on
on off off off
off on
on off
on on
on on off off
off on
on off
on on
LocNegRx LocNegTx RemNegRx RemNegTx
off off off off
off off off off
off off off off
off off off off
Interfaces
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