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.

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