the switch 10/100 and 10/100/1000 ports configure themselves to operate at the speed of attached devices. if the attached ports do not support autonegotiation, you can explicitly set the speed and duplex parameters. connecting devices that do not autonegotiate or that have their speed and duplex parameters manually set can reduce performance or result in no linkage.

    to maximize performance, choose one of these methods for configuring the ethernet ports:

    1?let the ports autonegotiate both speed and duplex.

    2?set the port speed and duplex parameters on both ends of the connection.

    follow these steps to connect to 10base-t, 100base-tx or 1000base-t devices:

    to prevent electrostatic-discharge (esd) damage, follow your normal board and component handling procedures.

    step 1 when connecting to workstations, servers, routers, and cisco ip phones, connect a straight-through cable to an rj-45 connector on the front panel. (see figure 3-40.) when connecting to switches or repeaters, use a crossover cable.

    (see the “cable and adapter specifications” section on page b-6 for cable-pinout descriptions.)

    when connecting to 1000base-t-compatible devices, be sure to use a twisted four-pair, category 5 cable.

    on switches running cisco ios release 12.1(14)ea1 or later, you can use the mdix auto command in the cli to enable the automatic crossover feature. when the automatic crossover feature is enabled, the switch detects the required cable type for copper ethernet connections and configures the interfaces accordingly. therefore, you can use either a crossover or a straight-through cable for connections to a copper 10/100 or 10/100/1000 port on the switch, regardless the type of device on the other end of the connection.

    the automatic crossover feature is disabled by default. for configuration information for this feature, refer to the switch software configuration guide or the switch command reference.

    step 2 connect the other end of the cable to an rj-45 connector on the other device. the port led turns on when both the switch and the connected device have established link.

    the port led is amber while spanning tree protocol (stp) discovers the topology and searches for loops. this takes about 30 seconds, and then the port led turns green. if the port led does not turn on, the device at the other end might not be turned on, or there might be a cable problem or a problem with the adapter installed in the attached device. see chapter 4, “troubleshooting,” for solutions to cabling problems.

    step 3 reconfigure and reboot the connected device if necessary.

    step 4 repeat steps 1 through 3 to connect each device.