13-13
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 13 Configuring Interface Characteristics Using the Switch USB Ports
possible, to maintain high performance, forwarding is done by the switch hardware. However, only IPv4
packets with Ethernet II encapsulation are routed in hardware. Non-IP traffic and traffic with other
encapsulation methods are fallback-bridged by hardware.
• The routing function can be enabled on all SVIs and routed ports. The switch routes only IP traffic.
When IP routing protocol parameters and address configuration are added to an SVI or routed port,
any IP traffic received from these ports is routed. For more information, see Chapter 42,
“Configuring IP Unicast Routing,” Chapter 48, “Configuring IP Multicast Routing,” and
Chapter 49, “Configuring MSDP.”
• Fallback bridging forwards traffic that the switch does not route or traffic belonging to a nonroutable
protocol, such as DECnet. Fallback bridging connects multiple VLANs into one bridge domain by
bridging between two or more SVIs or routed ports. When configuring fallback bridging, you assign
SVIs or routed ports to bridge groups with each SVI or routed port assigned to only one bridge
group. All interfaces in the same group belong to the same bridge domain. For more information,
see Chapter 50, “Configuring Fallback Bridging.”
Note Routing and fallback bridging are not supported on switches running the LAN base feature set.
Using the Switch USB Ports
• USB Mini-Type B Console Port, page 13-13
• USB Type A Port, page 13-16

USB Mini-Type B Console Port

The switch has two console ports available—a USB mini-Type B console connection and an RJ-45
console port. Console output appears on devices connected to both ports, but console input is active on
only one port at a time. The USB connector takes precedence over the RJ-45 connector.
Note Windows PCs require a driver for the USB port. See the hardware installation guide for driver
installation instructions.
Use the supplied USB Type A-to-USB mini-Type B cable to connect a PC or other device to the switch.
The connected device must include a terminal emulation application. When the switch detects a valid
USB connection to a powered-on device that supports host functionality (such as a PC), input from the
RJ-45 console is immediately disabled, and input from the USB console is enabled. Removing the USB
connection immediately reenables input from the RJ-45 console connection. An LED on the switch
shows which console connection is in use.

Console Port Change Logs

At software startup, a log shows whether the USB or the RJ-45 console is active. Each switch in a stack
issues this log. Every switch always first displays the RJ-45 media type.
In the sample output, switch 1 has a connected USB console cable. Because the bootloader did not
change to the USB console, the first log from switch 1 shows the RJ-45 console. A short time later, the
console changes and the USB console log appears. Switch 2 and switch 3 have connected RJ-45 console
cables.