Loopback Interfaces; Licensing Requirements For Layer 3 Interfaces; Guidelines And Limitations For Layer 3 Interfaces - Cisco Nexus 3548 Configuration Manual
Nx-os interfaces release 9x
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Also See for Nexus 3548:
- Command reference manual (556 pages) ,
- Configuration manual (230 pages) ,
- Installation manual (112 pages)
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Configuring Layer 3 Interfaces
Note
You cannot delete the VLAN interface for VLAN 1.
You can route across VLAN interfaces to provide Layer 3 inter-VLAN routing by configuring a VLAN
interface for each VLAN that you want to route traffic to and assigning an IP address on the VLAN interface.
For more information on IP addresses and IP routing, see the Unicast Routing Configuration Guide for your
device.
The following figure shows two hosts connected to two VLANs on a device. You can configure VLAN
interfaces for each VLAN that allows Host 1 to communicate with Host 2 using IP routing between the VLANs.
VLAN 1 communicates at Layer 3 over VLAN interface 1and VLAN 10 communicates at Layer 3 over VLAN
interface 10.
Figure 3: Connecting Two VLANs with VLAN Interfaces
Loopback Interfaces
A loopback interface is a virtual interface with a single endpoint that is always up. Any packet that is transmitted
over a loopback interface is immediately received by this interface. Loopback interfaces emulate a physical
interface.
You can use loopback interfaces for performance analysis, testing, and local communications. Loopback
interfaces can act as a termination address for routing protocol sessions. This loopback configuration allows
routing protocol sessions to stay up even if some of the outbound interfaces are down.
Licensing Requirements for Layer 3 Interfaces
This feature does not require a license. Any feature not included in a license package is bundled with the Cisco
NX-OS system images and is provided at no extra charge to you. For a complete explanation of the Cisco
NX-OS licensing scheme, see the Cisco NX-OS Licensing Guide.
Guidelines and Limitations for Layer 3 Interfaces
Layer 3 interfaces have the following configuration guidelines and limitations:
• If you change a Layer 3 interface to a Layer 2 interface, Cisco NX-OS shuts down the interface, reenables
the interface, and removes all configuration specific to Layer 3.
Cisco Nexus 3548 Switch NX-OS Interfaces Configuration Guide, Release 9x
Loopback Interfaces
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