Switch Features - 3Com OfficeConnect 3CDSG8 User Manual

Device Specifications and Features
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Electrical
Input Voltage
Current Rating
Maximum Power
Consumption
Max Heat Dissipation
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Switch Features

This section describes the device features. The system supports the following features:
Table 6 Features of the OfficeConnect Managed Gigabit Switch
Feature
Auto Negotiation
Automatic MAC Addresses Aging
Back Pressure
Address Resolution Protocol (ARP)
Class Of Service (CoS)
12V DC
1 Amp (Max)
23.9 BTU/hr (7.6 Watts)
19 BTU/hr
Description
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
MAC addresses from which no traffic is received for a given period are
aged out. This prevents the Bridging Table from overflowing.
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.
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.
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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