Users Guide

Switch Feature Overview 89
Auto-MDI/MDIX Support
The switch supports auto-detection between crossed and straight-through
cables. Media-Dependent Interface (MDI) is the standard wiring for end
stations, and the standard wiring for hubs and switches is known as Media-
Dependent Interface with Crossover (MDIX). Auto-negotiation must be
enabled for the switch to detect the wiring configuration. NBASE-T ports
(2.5G and 5G) do not support auto-detection. Use the correct crossover or
straight-through cable on 2.5/5G NBASE-T interfaces.
VLAN-Aware MAC-based Switching
Packets arriving from an unknown source address are sent to the CPU and
added to the Hardware Table. Future packets addressed to or from this
address are more efficiently forwarded.
Back Pressure Support
On half-duplex links, a receiver may prevent buffer overflows by jamming the
link so that it is unavailable for additional traffic. On full-duplex links, a
receiver may send a PAUSE frame indicating that the transmitter should
cease transmission of frames for a specified period.
When flow control is enabled, the Dell EMC Networking N-Series switches
will observe received PAUSE frames or jamming signals, but will not issue
them when congested.
NOTE: Dell EMC Networking N2000/N2100-ON/N3000/N3100-ON/N4000 Series
switches do not support half-duplex operation.