3Com manual Electrical, Features of the Baseline Switch 2924-PWR Plus

216APPENDIX B: DEVICE SPECIFICATIONS AND FEATURES

Electrical

Line Frequency	50/60 Hz
Input Voltage	100–240 Vac (auto range)
Current Rating	5.1 Amp (Max)
Maximum Power	350 Watts
Consumption
Max Heat Dissipation	1194.6 BTU/hr

Switch Features This section describes the device features. The system supports the following features:

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.