3Com 2924-PWR - Manual (Page 216)

216 A PPENDIX B: D EVICE S PECIFICATIONS AND F EATURES
Electrical
Switch Features This section describes the device features. The system supports the
following features:
Line Frequency 50/60 Hz
Input Voltage 100–240 Vac (auto range)
Current Rating 5.1 Amp (Max)
Maximum Power
Consumption 350 Watts
Max Heat Dissipation 1194.6 BTU/hr
Table 9 Features of the Baseline Switch 2924-PWR Plus
Feature Description
Auto Negotiation The purpose of auto negotiation is to allow a device to advertise modes of
operation. The auto negotiation function provides the means to exchange
information between two devices that share a point-to-point link
segment, and to automatically configure both devices to take maximum
advantage of their abilities.
Auto negotiation is performed totally within the physical layers during link
initiation, without any additional overhead to either the MAC or higher
protocol layers. Auto negotiation allows the ports to do the following:
■ Advertise their abilities
■ Acknowledge receipt and understanding of the common modes of
operation that both devices share
■ Reject the use of operational modes that are not shared by both
devices
■ Configure each port for the highest-level operational mode that both
ports can support
Automatic MAC Addresses Aging MAC addresses from which no traffic is received for a given period are
aged out. This prevents the Bridging Table from overflowing.
Back Pressure On half duplex links, the receiver may employ back pressure (i.e. occupy
the link so it is unavailable for additional traffic), to temporarily prevent
the sender from transmitting additional traffic. This is used to prevent
buffer overflows.
Address Resolution Protocol (ARP) ARP converts between IP addresses and MAC (i.e., hardware) addresses.
ARP is used to locate the MAC address corresponding to a given IP
address. This allows the switch to use IP addresses for routing decisions
and the corresponding MAC addresses to forward packets from one hop
to the next.
Class Of Service (CoS) Provide traffic belonging to a group preferential service (in terms of
allocation of system resources), possibly at the expense of other traffic.