Dell Force10 S4820T FTOS Command Reference Guide - Page 609

Parameters rx on rx off tx on tx off threshold (C-Series and S-Series only) Enter the keywords rx on to process the received flow control frames on this port. This is the default value for the receive side. Enter the keywords rx off to ignore the received flow control frames on this port. Enter the keywords tx on to send control frames from this port to the connected device when a higher rate of traffic is received. This is the default value on the send side. Enter the keywords tx off so that flow control frames are not sent from this port to the connected device when a higher rate of traffic is received. When tx on is configured, you can set the threshold values for: Number of flow-control packet pointers: 1 to 2047 (default = 75) Flow-control buffer threshold in KB: 1 to 2013 (default = 49KB) Flow-control discard threshold in KB: 1 to 2013 (default= 75KB) Defaults C-Series: rx off tx off E-Series: rx on tx on S-Series: rx off tx off S4810: rx on tx off S4820T: rx on tx off Command Modes INTERFACE Command History Version 8.3.19.0 Version 8.3.7.0 Version 8.1.1.0 Version 6.5.1.9 and 7.4.1.0 Version 7.8.1.0 Introduced on S4820T Introduced on S4810 Introduced on E-Series ExaScale Introduced on E-Series Introduced on C-Series and S-Series with thresholds 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 multicast address. The pause: • Starts when either the packet pointer or the buffer threshold is met (whichever is met first). When the discard threshold is met, packets are dropped. • Ends when both the packet pointer and the buffer threshold fall below 50% of the threshold settings. The discard threshold defines when the interface starts dropping the packet on the interface. This may be necessary when a connected device does not honor the flow control frame sent by the S-Series. The discard threshold should be larger than the buffer threshold so that the buffer holds at least hold at least 3 packets. Interfaces | 609