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Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 9 Configuring Interfaces
Understanding Interface Types
When you configure an EtherChannel, you create a port-channel logical interface and assign an interface
to the EtherChannel. For Layer 3 interfaces, you manually create the logical interface by using the
interface port-channel global configuration command. Then you manually assign an interface to the
EtherChannel by using the channel-group interface configuration command. For Layer 2 interfaces, 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
Chapter 28, “Configuring EtherChannels.”
Ethernet Flow Points
An Ethernet Flow Point (EFP) is a logical interface that connects an Ethernet Virtual Connection (EVC)
bridge domain to a physical port in a switch. Configuring a service instance on an interface creates a
pseudoport or EFP on which you configure EVC features.
You can configure EFP service instances only on Layer 2 ports. You can configure an EtherChannel with
a service instance, but you cannot add an interface to a channel group if it has a service instance
configured on it. EFPs do not support routing. EFPs do not support switchport commands.
Switch interfaces configured with service instances support a different range of features than interfaces
that do not have service instances. For more information on EVCs, see
Chapter 11, “Configuring
Ethernet Virtual Connections (EVCs).”
Connecting Interfaces
Devices within a single VLAN can communicate directly through any switch. Ports in different VLANs
cannot exchange data without going through a routing device. With a standard Layer 2 switch, ports in
different VLANs have to exchange information through a router. By using the switch with routing
enabled, when you configure both VLAN 20 and VLAN 30 with an SVI to which an IP address is
assigned, packets can be sent from Host A to Host B directly through the switch with no need for an
external router (
Figure 9-1
).
Figure 9-1
Connecting VLANs with the Switch
You can enable routing on all SVIs and routed ports on the switch. Whenever possible, to maintain high
performance, forwarding is done by the switch hardware. However, only IP Version 4 packets with
Ethernet II encapsulation can be routed in hardware. The switch routes only IP traffic. When IP routing
Host A
SVI 1
172.20.128.1
172.20.129.1
SVI 2
Layer 3 switch
with routing enabled
VLAN 20
Host B
VLAN 30
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