1000Base-T Ports; Dual Personality Interfaces - ZyXEL Communications Dimension GS-2024 User Manual

Chapter 3 Hardware Overview

3.1.1 1000Base-T Ports

The Switch has 24 1000Base-T auto-negotiating, auto-crossover Ethernet ports. In 100/1000
Mbps Gigabit Ethernet, the speed can be 100 Mbps or 1000 Mbps. The duplex mode can be
both half or full duplex at 100 Mbps and full duplex only at 1000 Mbps.
An auto-negotiating port can detect and adjust to the optimum Ethernet speed (100/1000
Mbps) and duplex mode (full duplex or half duplex) of the connected device.
An auto-crossover (auto-MDI/MDI-X) port automatically works with a straight-through or
crossover Ethernet cable.
Two of the 1000Base-T Ethernet ports are paired with a mini-GBIC slot to create a dual
personality interface. The Switch uses up to one connection for each mini-GBIC and
1000Base-T Ethernet pair. The mini-GBIC slots have priority over the Gigabit ports. This
means that if a mini-GBIC slot and the corresponding Gigabit port are connected at the same
time, the Gigabit port will be disabled.
When auto-negotiation is turned on, a Gigabit port negotiates with the peer automatically to
determine the connection speed and duplex mode. If the peer Ethernet port does not support
auto-negotiation or turns off this feature, the Switch determines the connection speed by
detecting the signal on the cable and using half duplex mode. When the Switch's auto-
negotiation is turned off, a Gigabit port uses the pre-configured speed and duplex mode when
making a connection, thus requiring you to make sure that the settings of the peer Ethernet port
are the same in order to connect.
3.1.1.1 Default Ethernet Settings
The factory default negotiation settings for the Ethernet ports on the Switch are:
• Speed: Auto
• Duplex: Auto
• Flow control: Off
• Link aggregation: Off
3.1.1.2 Auto-crossover
All ports are auto-crossover, that is auto-MDIX ports (Media Dependent Interface Crossover),
so you may use either a straight-through Ethernet cable or crossover Ethernet cable for all
Gigabit port connections. Auto-crossover ports automatically sense whether they need to
function as crossover or straight ports, so crossover cables can connect both computers and
switches/hubs.

3.1.2 Dual Personality Interfaces

Dual Personality interfaces comprise 1000Base-T/mini-GBIC combo ports. For each interface
you can connect either to the 1000Base-T port or the mini-GBIC port. The mini-GBIC ports
have priority over the 1000Base-T ports. This means that if a mini-GBIC port and the
corresponding 1000Base-T port are connected at the same time, the 1000Base-T port will be
disabled.
38
GS-2024 User's Guide