Dell S6000 FTOS 9.0(2.0) Command Line Reference Guide for the System - Page 421

Command History Version 9.0.2.0 Version 8.3.11.1 Version 8.2.1.0 Introduced on then S6000. Introduced on the Z9000. Introduced on the S4810 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 reception of frames with a destination address equal to this multi-cast address. 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. Consult Dell Force10TAC for information and assistance. • The only configuration applicable to half duplex ports is rx off tx off. The following error is returned: Can't configure flowcontrol when half duplex is configure, config ignored • Half duplex cannot be configured when the flow control configuration is on (default is rx on tx on). The following error is returned: Can't configure half duplex when flowcontrol is on, config ignored Note: The flow control must be off (rx off tx off) before configuring the half duplex. • Speeds less than 1 Gig cannot be configured when the asymmetric flow control configuration is on. The following error is returned: Can't configure speed