Cisco Systems IC-23 Bedienungsanleitung PDF herunterladen (Seite 23)

Configuring LAN Interfaces

Configuring a Hub Interface

IC-45

Cisco IOS Interface Configuration Guide

Enabling a Hub Port

To enable a hub port, use the following commands in global configuration mode:

Disabling or Enabling Automatic Receiver Polarity Reversal

On Ethernet hub ports only, the hub ports can invert, or correct, the polarity of the received data if the

port detects that the received data packet waveform polarity is reversed due to a wiring error. This receive

circuitry polarity correction allows the hub to repeat subsequent packets with correct polarity. When

enabled, this function is executed once after reset of a link fail state.

Automatic receiver polarity reversal is enabled by default. To disable this feature on a per-port basis, use

the following command in hub configuration mode:

To enable automatic receiver polarity reversal on a per-port basis, use the following command in hub

configuration mode:

Disabling or Enabling the Link Test Function

The link test function applies to Ethernet hub ports only. The Ethernet ports implement the link test

function as specified in the 802.3 10BASE-T standard. The hub ports will transmit link test pulses to any

attached twisted pair device if the port has been inactive for more than 8 to 17 ms.

If a hub port does not receive any data packets or link test pulses for more than 65 to 132 ms and the link

test function is enabled for that port, that port enters link fail state and cannot transmit or receive. The

hub port is enabled again when it receives four consecutive link test pulses or a data packet.

The link test function is enabled by default. To allow the hub to interoperate with 10BASE-T twisted-pair

networks that do not implement the link test function, the hub’s link test receive function can be disabled

on a per-port basis. To do so, use the following command in hub configuration mode:

Command Purpose

Step 1

hub ethernet number port [end-port]

Specifies the hub number and the hub port (or range of hub ports) and

enters hub configuration mode.

Step 2

no shutdown

Enables the hub ports.

Command Purpose

no auto-polarity

Disables automatic receiver polarity reversal.

Command Purpose

auto-polarity

Enables automatic receiver polarity reversal.

Command Purpose

no link-test

Disables the link test function.

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Cisco Systems IC-23 Bedienungsanleitung Seite 23