Port Configuration

With the Port Configuration page, you can:

Disabling or Enabling a Port

All ports are enabled by default.

To administratively disable a port:

  1. From the Status drop-down list, select Disable.
    The Actual Port Settings section displays the actual status of the port. An enabled port could have an actual status of DOWN if no device is connected to it.
  2. Click OK.
    A "linkdown" trap is sent to the management station if you configured an SNMP manager.
  3. In Cluster Manager, click Save Config to save the configuration change to nonvolatile memory.
    Note: Catalyst 1900 and 2820 switches automatically save configuration changes to nonvolatile memory, so this step is not required. Allow several seconds for changes to be saved to nonvolatile memory before resetting or turning off the switch.

To reenable a port, select Enable from the drop-down list, and click OK.

Changing the Duplex and Speed Settings

On 2900 and 3500 XL switches, Fast Ethernet ports can automatically match the duplex capability and the transmission speed of an attached device. Gigabit Ethernet ports on these switches can automatically match the duplex capability of an attached device. ATM ports do not autonegotiate duplex or speed settings.

Port speed on all Catalyst 1900 and 2820 switches is fixed at 100 Mbps or 10 Mbps. This table explains the default duplex settings on Catalyst 1900 and 2820 models:

Port  Type Default Duplex Setting
Catalyst 1900 and 2820 10BaseT Half duplex
Catalyst 1900 100BaseTX Autonegotiate
Catalyst 1900 100BaseFX Half duplex
Catalyst 2820 100BaseTX (switch ports) Half duplex
Catalyst 2820 100BaseTX (repeater ports) Half duplex

Note: Changing the port configuration can cause the Spanning-Tree Protocol (STP) to check for a new loop. While STP reconfigures, the port LED is amber for about 30 seconds.

To change the duplex and transmission speed settings:

  1. From the Duplex drop-down list, select Full, Half, or Auto.
    On Catalyst 1900 and 2820 switches, the default setting for all ports is Half duplex.
    On 2900 and 3500 XL switches, Fast Ethernet, Gigabit Ethernet, and GigaStack GBIC ports are set to Auto by default, and ATM ports are set to Full. To connect to a remote Fast Ethernet device that does not autonegotiate, you should explicitly set the duplex on the local device to a value other than Auto. Speed negotiation will work even if the other device does not autonegotiate. To connect to a remote Gigabit Ethernet device that does not autonegotiate, you should disable autonegotiation on the local device, and set the duplex and flow control parameters to be compatible with the remote device. ATM ports are always set to full duplex and do not autonegotiate.
    Note: Point-to-point GigaStack GBIC port connections operate in full-duplex mode. GigaStack GBIC stack connections operate in half-duplex mode.
  2. From the Speed drop-down list, select 10 Mbps, 100 Mbps, or Auto.
    On 2900 and 3500 XL switches, the default setting for Fast Ethernet ports is Auto; on Gigabit Ethernet ports, the default is 1000 Mbps and not configurable; and on ATM ports, the default is 155 Mbps and not configurable. You cannot configure transmission speed on Catalyst 1900 and 2820 switches.
  3. Click OK.
    Note: While you can configure settings for mixed multiple ports, some settings may not apply to all ports. For example, you can select half duplex from the drop-down list for a mixture of Ethernet, Gigabit Ethernet, and ATM ports, but the application applies the setting only to Ethernet and Gigabit Ethernet ports.
  4. In Cluster Manager, click Save Config to save the configuration change to nonvolatile memory.
    Note: Catalyst 1900 and 2820 switches automatically save configuration changes to nonvolatile memory, so this step is not required. Allow several seconds for changes to be saved to nonvolatile memory before resetting or turning off the switch.

Enabling or Disabling the Port Fast Feature

The Port Fast feature immediately brings a port from the blocking state into the forwarding state by eliminating the forwarding delay (the amount of time a port waits before changing from its Spanning-Tree Protocol (STP) learning and listening states to the forwarding state.

The Port Fast feature is disabled by default. To enable it:

  1. From the Port Fast drop-down list, select Enable (if the port is connected to an end station).
    Note: The Port Fast feature does not apply to ATM ports.
  2. Click OK.
  3. In Cluster Manager, click Save Config to save the configuration change to nonvolatile memory.
    Note: Catalyst 1900 and 2820 switches automatically save configuration changes to nonvolatile memory, so this step is not required. Allow several seconds for changes to be saved to nonvolatile memory before resetting or turning off the switch.

To disable the Port Fast feature, select Disable from the drop-down list, and click OK.

Displaying the Settings for a Single Port

If you select a single port, the Port Configuration page automatically displays the actual port settings in the Actual Port settings section.

Note: If you select multiple ports, the Actual Ports Settings section does not appear on the Port Configuration page.

Displaying VLAN Information for a Single Port

If you select a single port, the Port Configuration page automatically displays the VLAN mode (static, dynamic, trunk, and so forth) and the VLANs to which the port belongs.

Note: If you select multiple ports, the VLAN Information section does not appear on the Port Configuration page.