Deployment Guide
Full–Switch
Command History
Version Description
9.11(0.0) Added support for monitor session.
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 ow 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 buer threshold is met (whichever is met rst). When the discard
threshold is met, packets are dropped.
• Ends when both the packet pointer and the buer threshold fall below 50% of the threshold settings.
The discard threshold denes when the interface starts dropping the packet on the interface. This may be
necessary when a connected device does not honor the ow control frame sent by the switch. The discard
threshold should be larger than the buer threshold so that the buer holds at least hold at least three packets.
Important Points to Remember
• Do not enable tx pause when buer carving is enabled. For information and assistance, consult Dell
Networking TAC.
• Asymmetric ow control (rx on tx off, or rx off tx on) setting for the interface port less than 100
Mb/s speed is not permitted. The following error is returned:
Can’t configure Asymmetric flowcontrol when speed <1G, config ignored
• The only conguration applicable to half duplex ports is rx off tx off. The following error is returned:
Cannot configure Asymmetric flowcontrol when speed <1G, config ignored>
• You cannot congure half duplex when the ow control conguration is on (default is rx on tx on). The
following error is returned: Cannot configure half duplex when flowcontrol is on,
config ignored
NOTE
: The ow control must be o (rx off tx off) before conguring the half duplex.
Example (partial)
Dell(conf-if-tengig-0/1)#show config
!
interface TenGigabitEthernet 0/1
no ip address
switchport
no negotiation auto
flowcontrol monitor session 5 rx off tx on
no shutdown
...
Example (Values) This Example shows how the Dell Networking OS negotiates the ow 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
530 Interfaces