Configuring a Loopback Interface

A loopback interface is a virtual interface with a single endpoint that is always up. Any packet transmitted over a loopback interface is immediately received by this interface. Loopback interfaces emulate a physical interface. You can configure up to 1024 loopback interfaces, numbered 0 to 1023.

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.

For more information, see the Cisco Nexus 9000 Series NX-OS Interfaces Configuration Guide:

https://www.cisco.com/c/en/us/support/switches/nexus-9000-series-switches/products-installation-and-configuration-guides-list.html/

Configuring a Description

 Configuring a Description

POST http://<mgmt0_IP>/api/mo/sys/intf.json

{
  "interfaceEntity": {
    "children": [
      {
        "l3LbRtdIf": {
          "attributes": {
            "descr": "SampleString_123",
            "id": "lo123"
}}}]}}

{
    imdata:[]
}

<System>
  <intf-items>
    <lb-items>
      <LbRtdIf-list>
        <id>lo123</id>
        <descr>SampleString_123</descr>
      </LbRtdIf-list>
    </lb-items>
  </intf-items>
</System>

Note: This example was added in Release 9.3(1).

CLI Commands

The CLI commands are equivalent to the payload examples displayed in the pane on the right. Click the DME tab in the top-left corner of the right pane to view the JSON payload. Click the YANG tab to view the XML payload.

interface loopback 123
description SampleString_123

Verifying a DME Configuration

The following table contains the distinguished name (DN) for each managed object (MO) in the DME payload. Issue a GET request using the DN to verify the configuration was posted or to get information about the configured properties of a particular object.

MO	DN
interfaceEntity	sys/intf
l3LbRtdIf	sys/intf/lb-[lo123]

l3LbRtdIf Properties

The following table contains information about the l3LbRtdIf properties in the DME payload. For more information about the properties and MOs, see the NX-API DME Model Reference linked in the Related Documentation section below.

Property Name	Data Type	Description	Values
descr	naming:Descr1024 string:Basic	Additional descriptive information about the object.	RANGE: Min: "0" Max: "254"
id	nw:IfId (base:IfIndex)	An identifier .	Must match first field in the output of `show intf brief`. Example: Eth1/1 or Vlan100

Related Documentation

For other CLI options, see the Cisco Nexus 9000 Series NX-OS Command Reference:

http://www.cisco.com/c/en/us/support/switches/nexus-9000-series-switches/products-command-reference-list.html

See the NX-API DME Model Reference for detailed information about classes and attributes described in the payload:

https://developer.cisco.com/site/nx-os/docs/nexus-model-reference/

For information about using the payloads, see the Cisco Nexus 9000 Series NX-OS Programmability Guide:

https://www.cisco.com/c/en/us/support/switches/nexus-9000-series-switches/products-programming-reference-guides-list.html

Deleting a Description

 Deleting a Description

POST http://<mgmt0_IP>/api/mo/sys/intf.json

{
  "interfaceEntity": {
    "children": [
      {
        "l3LbRtdIf": {
          "attributes": {
            "descr": "",
            "id": "lo123"
}}}]}}

{
    imdata:[]
}

<System>
  <intf-items>
    <lb-items>
      <LbRtdIf-list>
        <id>lo123</id>
        <descr></descr>
      </LbRtdIf-list>
    </lb-items>
  </intf-items>
</System>