Etherchannel Port Groups; Dual-Purpose Uplink Ports; Power Over Ethernet Ports - Cisco Catalyst 2975 Software Configuration Manual

Understanding Interface Types
SVIs are created the first time that you enter the vlan interface configuration command for a VLAN
interface. The VLAN corresponds to the VLAN tag associated with data frames on an encapsulated trunk
port or the VLAN ID configured for an access port. Configure a VLAN interface for each VLAN for
which you want to route traffic, and assign it an IP address. For more information, see the
Assigning IP Information" section on page
When you create an SVI, it does not become active until it you associate it with a physical port.
Note

EtherChannel Port Groups

EtherChannel port groups treat multiple switch ports as one switch port. An EtherChannel port group
acts as a single logical port for high-bandwidth connections between switches or between switches and
servers. An EtherChannel balances the traffic load across the links in the channel. If a link within the
EtherChannel fails, traffic previously carried over the failed link changes to the remaining links.You can
group multiple trunk ports into one logical trunk port or multiple access ports into one logical access
port. Most protocols operate over either single ports or aggregated switch ports and do not recognize the
physical ports within the port group. The DTP, the Cisco Discovery Protocol (CDP), and the Port
Aggregation Protocol (PAgP) operate only on physical ports.
When you configure an EtherChannel, you create a port-channel logical interface and assign an interface
to the EtherChannel. Use the channel-group interface configuration command to dynamically create the
port-channel logical interface. This command binds the physical and logical ports together.
For more information, see

Dual-Purpose Uplink Ports

Some switches support dual-purpose uplink ports. Each uplink port is considered as a single interface
with dual front ends—an RJ-45 connector and a small form-factor pluggable (SFP) module connector.
The dual front ends are not redundant interfaces, and the switch activates only one connector of the pair.
By default, the switch dynamically selects the interface 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. For information about configuring speed and duplex settings for a dual-purpose
uplink, see the
Each uplink port has two LEDs: one shows the status of the RJ-45 port, and one shows the status of the
SFP module port. The port LED is on for whichever connector is active. For more information about the
LEDs, see the hardware installation guide.

Power over Ethernet Ports

PoE switch ports automatically supply power to these connected devices (if the switch senses that there
is no power on the circuit):
•
•
Catalyst 2975 Switch Software Configuration Guide
12-4
Chapter 37, "Configuring EtherChannels and Link-State Tracking."
"Setting the Interface Speed and Duplex Parameters" section on page
Cisco pre-standard powered devices (such as Cisco IP Phones and Cisco Aironet access points)
IEEE 802.3 af-compliant powered devices
Chapter 12
3-15.
Configuring Interface Characteristics
"Manually
12-20.
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