230 APPENDIX B: D EVICE S PECIFICATIONS AND FEATURESElectricalSwitch Features This section describes the device features. The system supports thefollowing features:Line Frequency 50/60 HzInput Voltage 100–240 Vac (auto range)Current Rating 2.0 Amp (Max)Maximum PowerConsumption200.3 BTU/hr (88 Watts)Max Heat Dissipation 200.3 BTU/hrTable 13 Features of the OfficeConnect Managed Fast Ethernet PoE SwitchFeature DescriptionAuto Negotiation The purpose of auto negotiation is to allow a device to advertise modes ofoperation. The auto negotiation function provides the means to exchangeinformation between two devices that share a point-to-point linksegment, and to automatically configure both devices to take maximumadvantage of their abilities.Auto negotiation is performed totally within the physical layers during linkinitiation, without any additional overhead to either the MAC or higherprotocol layers. Auto negotiation allows the ports to do the following:■ Advertise their abilities■ Acknowledge receipt and understanding of the common modes ofoperation that both devices share■ Reject the use of operational modes that are not shared by bothdevices■ Configure each port for the highest-level operational mode that bothports can supportAutomatic MAC Addresses Aging MAC addresses from which no traffic is received for a given period areaged out. This prevents the Bridging Table from overflowing.Back Pressure On half duplex links, the receiver may employ back pressure (i.e. occupythe link so it is unavailable for additional traffic), to temporarily preventthe sender from transmitting additional traffic. This is used to preventbuffer 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 IPaddress.Class Of Service (CoS) Provide traffic belonging to a group preferential service (in terms ofallocation of system resources), possibly at the expense of other traffic.Command Line Interface The Command Line Interface (CLI) is an interface using a serial connectionthat allows the switch to be configured.
