72 Switch Feature Overview
Auto-MDI/MDIX Support
Your 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 MDIX to detect the wiring configuration.
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 Networking series switches will
observe received PAUSE frames or jamming signals, but will not issue them
when congested.
Auto Negotiation
Auto negotiation allows the switch to adv ertise modes of operation. The auto
negotiation function provides the means to exchange information between
two switches that share a point-to-point link segment, and to automatically
configure both switches to take maximum advantage of their transmission
capabilities.
Dell Networking series switches enhance auto negotiation by providing
configuration of port advertisement. Port advertisement allows the system
administrator to configure the port speeds that are advertised.
For information about configuring auto negotiation, see "Configuring Port
Characteristics" on page477.