LevelOne GSW-0840T Manuale Utente

 

9

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. 

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. 

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. 

Every Ethernet data packet includes both source and destination addresses. This Six (6) bytes ID 
is called the MAC (Media Access Control) Address.