Auto-Negotiation; Multicast Filtering - 3Com SuperStack 3C17300 Implementation Manual

Switch Features Explained 17

Auto-negotiation

Auto-negotiation allows ports to auto-negotiate port speed,
duplex-mode (only at 10 Mbps and 100 Mbps) and flow control. When
auto-negotiation is enabled (default), a port "advertises" its maximum
capabilities — these capabilities are by default the parameters that
provide the highest performance supported by the port.
For details of the auto-negotiation features supported by your Switch,
please refer to the Management Quick Reference Guide that
accompanies your Switch.
Ports operating at 1000 Mbps only support full duplex mode.
Duplex
Full duplex mode allows packets to be transmitted and received
simultaneously and, in effect, doubles the potential throughput of a link.
Flow Control
All Switch ports support flow control, which is a mechanism that
minimizes packet loss during periods of congestion on the network.
Flow control is supported on ports operating in half duplex mode, and is
implemented using the IEEE 802.3x standard on ports operating in full
duplex mode.
Smart Auto-sensing
Smart auto-sensing allows auto-negotiating multi-speed ports, such as
10/100 Mbps or 10/100/1000 Mbps, to monitor and detect high error
rates, or problems in the "physical" interconnection to another port. The
port reacts accordingly by tuning the link from its higher speed to the
lower supported speed to provide an error-free connection to the
network.
For more information about auto-negotiation and port capabilities, see
Chapter 2 "Optimizing Bandwidth".

Multicast Filtering

Multicast filtering allows the Switch to forward multicast traffic to only
the endstations that are part of a predefined multicast group, rather than
broadcasting the traffic to the whole network.
The multicast filtering system supported by your Switch uses IGMP
(Internet Group Management Protocol) snooping to detect the