Dell PowerConnect 5548 User Guide - Page 380
Flow Control, Back Pressure, Port Default Settings, Table 10-1., Function
View all Dell PowerConnect 5548 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 380 highlights
irrelevant. The standard wiring for end stations is known as MDI (Media Dependent Interface), and the standard wiring for hubs and switches is known as MDIX. Flow Control The device supports 802.3x flow control for ports configured to Full Duplex mode. By default, this feature is enabled on all ports, and it can be disabled per port. Flow control creates a lossless link with no packet loss. The flow control mechanism enables the receiving side to signal to the transmitting side that transmission must temporarily be halted to prevent buffer overflow. This signaling is done by sending PAUSE frames. The ports that receives pause frames stops transmitting traffic. Flow control on the device works in Receive-Only mode, meaning that the interfaces with enabled flow control receive PAUSE frames, but do not send them. When flow control is enabled, the system buffers are allocated per port so that if the buffers of one port are consumed, other ports will still have their free buffers. Back Pressure The device supports back pressure for ports configured to Half Duplex mode. By default, this feature is disabled, and it can be enabled per port. The back-pressure mechanism prevents the sender from transmitting additional traffic temporarily. The receiver may occupy a link so it becomes unavailable for additional traffic. Port Default Settings Table 12-1 describes the port default settings. Table 10-1. Port Default Settings Function Port speed and mode Port forwarding state Default Setting 10/100/1000 BaseT copper: auto-negotiation SFP+1000/10G Mbps full duplex, auto discovery Enabled 380 Dell PowerConnect 55xx Systems User Guide