Overview - Dell PowerConnect 5548P System User's Manual

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Overview

This section includes a description of port features and describes the
following:
• Auto-Negotiation
• MDI/MDIX
• Flow Control
• Back Pressure
• Port Default Settings
Auto-Negotiation
Auto-negotiation enables automatic detection of speed, duplex mode and
flow control on all switching 10/100/1000BaseT ports. Auto-negotiation is
enabled on all ports by default.
Auto-negotiation is a mechanism established between two link partners to
enable a port to advertise its transmission rate, duplex mode and flow control
abilities to its partner. Both ports then operate at the highest common
denominator.
If connecting a Network Interface Card (NIC) that does not support auto-
negotiation or is not set to auto-negotiation, both the device switching port
and the NIC must be manually set to the same speed and duplex mode.
If the station, on the other side of the link, attempts to auto-negotiate with a
device 100BaseT port that is configured to full duplex, the auto-negotiation
results in the station attempting to operate in half duplex.
MDI/MDIX
The device supports auto-detection of straight-through and crossed cables on
all 10/100/1000BaseT ports. This feature is part of auto-negotiation and is
enabled when Auto-negotiation is enabled.
When the MDI/MDIX (Media Dependent Interface with Crossover) is
enabled, the automatic correction of errors in cable selection is possible, thus
making the distinction between a straight-through cable and a crossover cable
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Dell PowerConnect 55xx Systems User Guide
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