Configuring Interface Speed And Duplex Mode; Speed And Duplex Configuration Guidelines - Cisco Catalyst 3120 Software Manual

Chapter 10 Configuring Interface Characteristics
Table 10-2
Feature
Port Fast
Auto-MDIX

Configuring Interface Speed and Duplex Mode

Ethernet interfaces on the switch operate at 10, 100, 1000, or 10,000 Mb/s and in either full- or
half-duplex mode. In full-duplex mode, two stations can send and receive traffic at the same time.
Normally, 10-Mb/s ports operate in half-duplex mode, which means that stations can either receive or
send traffic.
Switch models include external Gigabit Ethernet (10/100/1000-Mb/s) ports, 10-Gigabit Ethernet ports,
internal 1000 Mb/s ports, and small form-factor pluggable (SFP) module slots supporting SFP modules.
These sections describe how to configure the interface speed and duplex mode:
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•

Speed and Duplex Configuration Guidelines

When configuring an interface speed and duplex mode, note these guidelines:
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OL-12247-01
Default Layer 2 Ethernet Interface Configuration (continued)
Speed and Duplex Configuration Guidelines, page 10-17
Setting the Interface Speed and Duplex Parameters, page 10-18
The 10-Gigabit Ethernet ports do not support the speed and duplex features. These ports operate
only at 10,000 Mb/s and in full-duplex mode.
The external Gigabit Ethernet (10/100/1000-Mb/s) ports support all speed options and all duplex
options (auto, half, and full). However, Gigabit Ethernet ports operating at 1000 Mb/s do not support
half-duplex mode.
The internal Ethernet management ports do not support the speed and duplex features. These ports
operate only at 1000 Mb/s and in full-duplex mode.
For SFP module ports, the speed and duplex CLI options change depending on the SFP module type:
)The 1000BASE-SX SFP module ports support the nonegotiate keyword in the speed interface
–
configuration command. Duplex options are not supported.
The 1000BASE-T SFP module ports support the same speed and duplex options as the
–
10/100/1000-Mb/s ports.
For information about which SFP modules are supported on your switch, see the product release
notes.
If both ends of the line support autonegotiation, we highly recommend the default setting of auto
negotiation.
If one interface supports autonegotiation and the other end does not, configure duplex and speed on
both interfaces; do not use the auto setting on the supported side.
When STP is enabled and a port is reconfigured, the switch can take up to 30 seconds to check for
loops. The port LED is amber while STP reconfigures.
Default Setting
Disabled. See the "Default Optional Spanning-Tree
Configuration" section on page
Enabled.
Note
Cisco Catalyst Blade Switch 3120 for HP Software Configuration Guide
Configuring Ethernet Interfaces
19-12.
10-17