9-18
Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 9 Configuring Interfaces
Configuring Ethernet Interfaces
Each dual-purpose port is considered as a single interface with dual front ends (an RJ-45 connector and
an SFP module connector). The dual front ends are not redundant interfaces; the switch activates only
one connector of the pair.
By default, the dual-purpose ports are user-network interfaces (UNIs) and the SFP-only module ports
are network node interfaces (NNIs). If the switch is running the metro IP access image, any number of
ports that can be configured as NNIs. If the switch is running the metro base or metro access image, you
can configure only four ports as NNIs. When running these images on an ME 3400-12CS switch, if you
want to configure a dual-purpose port as an NNI, you must first change the port type of an SFP-only
module port to UNI by entering the port-type uni interface configuration command so as not to exceed
the switch maximum of four NNIs.
By default, the switch dynamically selects the dual-purpose port media type that first links up. However,
you can use the media-type interface configuration command to manually select the RJ-45 connector or
the SFP-module connector. In auto-select mode, the switch gives preference to SFP mode if both copper
and fiber-optic signals are simultaneously detected.
Beginning in privileged EXEC mode, follow these steps to select which dual-purpose media type to
activate. This procedure is optional.
To return to the default setting, use the no media-type interface configuration command.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify the dual-purpose port to be configured, and enter interface
configuration mode.
Step 3 media-type {auto-select | rj45 | sfp}Select the active interface and media type of a dual-purpose port. The
keywords have these meanings:
• auto-select—The switch dynamically selects the media type. This is the
default. When a linkup is achieved, the switch disables the other type
until the active link goes down. When the active link goes down, the
switch enables both types until one of them links up. In auto-select
mode, the switch configures both types with autonegotiation of speed
and duplex (the default).
• rj45—The switch disables the SFP module interface. If you connect a
cable to the SFP port, it cannot attain a link even if the RJ-45 side is
down or is not connected. In this mode, the dual-purpose port behaves
like a 10/100/1000BASE-TX interface. You can configure the speed and
duplex settings consistent with this interface type.
• sfp—The switch disables the RJ-45 interface. If you connect a cable to
the RJ-45 port, it cannot attain a link even if the SFP side is down or if
the SFP module is not present. Based on the type of installed SFP
module, you can configure the speed and duplex settings consistent with
this interface type.
Step 4 end Return to privileged EXEC mode.
Step 5 show interfaces interface-id
transceiver properties Verify your setting.
Step 6 copy running-config startup-config (Optional) Save your entries in the configuration file.