LevelOne OfficeCon GSW-0440T - Manual (Page 9)

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4 HELPFUL SUGGESTIONS
4.1 Prior to Installation
Before installing the Switch and connecting network devices, it is important to plan the network's
layout. Things you should consider include:
Dedicated Bandwidth: File servers and other high-traffic hardware improve their performance if
they have their own dedicated 10Mbps, 100Mbps, or 1000Mbps bandwidth.
Full-Duplex: Determine which devices support Full-Duplex connections.
Fast Ethernet & Gigabit Ethernet: Make sure rules for cable lengths and categories are followed.
100BASE-TX and 1000BASE-T have the same rules for cable and distance.
Auto-Negotiation: Devices with different speeds may be easily swapped when the other end of
the cable is fixed to a port with Auto-Negotiation.
4.2 Half- and Full-Duplex
The Switch supports both Half- and Full-Duplex modes for 10BASE-T and 100BASE-TX. But the
1000BASE-T only supports Full-Duplex mode.
In Half-Duplex mode: Data cannot be transmitted and received at the same time. Attached
devices must finish transmitting data before they can receive data.
In Full-Duplex mode: Data can be transmitted and received at the same time.
However:
Full-Duplex transmission is only possible between two devices with a dedicated link (e.g.,
Switch-Switch, Switch-PC)
Both devices must have Full-Duplex capability
Both devices must be set to Full-Duplex (e.g. Auto-Negotiation – Auto-Negotiation,
Non-Auto-Negotiation to Non-Auto-Negotiation)
The 100BASE-TX/10BASE-T or 1000BASE-T/100BASE-TX/10BASE-T ports on the Switch detect
and set the line's operating mode by using their Auto-Negotiation function.
4.3 Auto-Negotiation
Every 10/100/1000Mbps speed port on these Switches has a built-in "Auto-Negotiation" function.
This technology automatically sets the best possible bandwidth as soon as a connection is
established with another network device (usually at Power “On” or Reset). This is capability is
achieved via the Switch’s Auto-Negotiation function that automatically detects the modes and
speeds the second (attached) device is capable of.
Evaluating Auto-Negotiation Capability:
if attached device is: the Switch will automatically set its TP ports to operate at:
1000Mbps
with Auto-Negotiation
2000Mbps (1000BASE-T, Full-Duplex)
Note: Almost all 1000Mbps devices only operate in Full-Duplex mode.
100Mbps
no Auto-Negotiation
100Mbps (100BASE-TX, Half-Duplex)
100Mbps
with Auto-Negotiation
200Mbps (100BASE-TX, Full-Duplex)
10Mbps
no Auto-Negotiation
10Mbps (10BASE-T, Half-Duplex)
10Mbps
with Auto-Negotiation
20Mbps (10BASE-T, Full-Duplex)
Note: If the attached device is set to a fixed mode (ex: Forced Full-Duplex) it will not operate as an
Auto-Negotiation device.
4.4 MAC Address Table
Every Ethernet data packet includes both source and destination addresses. This Six (6) bytes ID
is called the MAC (Media Access Control) Address.