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Cisco Catalyst Blade Switch 3120 for HP Hardware Installation Guide
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Chapter 2 Switch Installation
Planning 10/100/1000 Ethernet Port Connections
Note You can use the mdix auto interface configuration command in the CLI to enable the automatic
medium-dependent interface crossover (auto-MDIX) feature. When the auto-MDIX feature is enabled,
the switch module 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 10/100/1000 module port on the switch module, regardless of the type of device
on the other end of the connection.
The auto-MDIX feature is enabled by default.
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 module 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 3, “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.
Planning 10/100/1000 Ethernet Port Connections
The 10/100/1000 Ethernet ports use standard RJ-45 connectors with Ethernet pinouts. The maximum
cable length is 328 feet (100 meters). The 100BASE-TX and 1000BASE-T traffic requires Category
5,
Category
5e, or Category 6 UTP cable. The 10BASE-T traffic can use Category 3 or Category 4 cable.
The autonegotiation feature is enabled by default on the switch. At this setting, the switch ports
configure themselves to operate at the speed of attached device. If the attached device does not support
autonegotiation, you can explicitly set the switch port speed and duplex parameters. To maximize
performance, either let the ports autonegotiate both speed and duplex, or set the port speed and duplex
parameters on both ends of the connection.
For simplified cabling, the automatic medium-dependent interface crossover (auto-MDIX) feature is
enabled by default on the switch. With auto-MDIX enabled, the switch detects the required cable type
for copper Ethernet connections and configures the interface accordingly. Therefore, you can use either
a crossover or a straight-through cable for connections to a switch 10/100/1000 Ethernet port regardless
of the type of device on the other end of the connection.
See the switch software configuration guide or the switch command reference on Cisco.com for more
information about enabling or disabling autonegotiation and auto-MDIX.
If auto-MDIX is disabled, use the guidelines in Table 2-1 to select the correct cable for connecting the
switch 10/100/1000 Ethernet ports to other devices. See the “Cable and Adapter Specifications” section
on page B-4 for cable-pinout descriptions.