Interface Ethernet

This feature manages Ethernet interface configuration including physical interfaces and subinterfaces. Ethernet interfaces provide the fundamental physical and logical connectivity for network devices, supporting various speeds from FastEthernet (100 Mbps) to multi-gigabit rates (1G - 800G) with comprehensive Layer 2 and Layer 3 capabilities.

• managed attribute: Controls whether Terraform continuously manages the interface configuration. When set to false, Terraform will push the initial configuration but will not continuously read it, detect drift, or reconcile changes. This is useful for:

  • Interfaces whose configuration changes dynamically
  • Interfaces modified by local scripts or automation
  • Interfaces where configuration drift should be allowed and not corrected
  • Default: true (Terraform fully manages the interface and reconciles drift)

• Usage example:

  interfaces:
    ethernets:
      - type: GigabitEthernet
        id: 0/0/0/1
        description: "Unmanaged interface"
        managed: false  # Terraform pushes initial config but ignores subsequent changes

• IOS-XR CLI no shutdown behavior: The default IOS-XR behavior for a physical interface with only the no shutdown command is to not populate that interface in the devices interface YANG model. This is due to no shutdown being a default configuation for a physical interface. If you define an interface in the YAML input with only no shutdown, Terraform’s create-then-read cycle will find nothing in the device state, resulting in a perpetual diff on every subsequent terraform plan/apply. This IOS-XR behavior can be seen in the example below.

RP/0/RP0/CPU0:ios#show ip int brief | inc GigabitEthernet0/0/0/1
GigabitEthernet0/0/0/1                 unassigned      Up              Up       default

RP/0/RP0/CPU0:ios#sh run interface GigabitEthernet0/0/0/1
% No such configuration item(s)

• Recommended workaround:

  • Ensure that 1 or more additional attributes are configured on a physical interface. Any attribute can be used. A common practice is a description or load-interval command.

  iosxr:
    devices:
      - name: router-1
        host: 10.10.10.1:57400
        configuration:
          interfaces:
              ethernets:
                - type: GigabitEthernet
                  id: 0/0/0/1
                  load_interval: 30 # Add
                  shutdown: false

  RP/0/RP0/CPU0:ios#sh run interface GigabitEthernet 0/0/0/1
  interface GigabitEthernet0/0/0/1
    load-interval 30

• Similar to the no shutdown behavior above, IOS-XR does not populate an interface in the YANG model when no configuration attributes are present. If you define an interface in the YAML input with no attributes defined, Terraform’s create-then-read cycle will find nothing in the device state, resulting in a terraform apply error perpetual diff on every subsequent terraform plan/apply.

• Recommended workaround:

  • Remove interfaces that have no attributes (other than type/id) from YAML input when removing the last attributes.

  iosxr:
    devices:
      - name: router-1
        host: 10.10.10.1:57400
        configuration:
          interfaces:
              ethernets:                  # Remove if last ethernet interface
                - type: GigabitEthernet   # Remove
                  id: 0/0/0/1             # Remove

MAC Address Formats

Interface fields accept MAC addresses in any of three formats:

1. colon-separated (e.g., "01:01:01:01:01:01")
2. dash-separated (e.g., "01-01-01-01-01-01")
3. dotted (e.g., "0101.0101.0101")

All 3 formats can be used interchangeably. The normalization layer coverts the user-specified format to colon-separated before sending to the device.

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1
      configuration:
        hostname: router-1
        interfaces:
          ethernets:
            - type: GigabitEthernet
              id: 0/0/0/1
              description: "Uplink to Core"
              shutdown: false
              mac_address: 00-1a-00-2b-00-3c
              mtu: 9000
              ipv4:
                address: 192.168.1.1
                netmask: 255.255.255.0

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1
      configuration:
        hostname: router-1
        interfaces:
          ethernets:
            - type: GigabitEthernet
              id: 0/0/0/2
              description: "Trunk Interface"
              shutdown: false
              subinterfaces:
                - id: 0/0/0/2.100
                  description: "VLAN 100"
                  encapsulation_dot1q_vlan_id: 100
                  ipv4:
                    address: 10.100.1.1
                    netmask: 255.255.255.0
                  vrf: CUSTOMER_A
                - id: 0/0/0/2.200
                  description: "VLAN 200"
                  encapsulation_dot1q_vlan_id: 200
                  ipv4:
                    address: 10.200.1.1
                    netmask: 255.255.255.0
                  vrf: CUSTOMER_B

iosxr:
  devices:
    - name: router-1
      host: 10.10.10.1
      configuration:
        hostname: router-1
        interfaces:
          ethernets:
            - type: TenGigE
              id: 0/0/0/3
              description: "WAN Interface"
              shutdown: false
              bandwidth: 10000000
              mtu: 9000
              load_interval: 30
              dampening_decay_half_life: 5
              dampening_reuse_threshold: 1000
              dampening_suppress_threshold: 2000
              dampening_max_suppress_time: 20
              ipv4:
                address: 203.0.113.1
                netmask: 255.255.255.252
                mtu: 1500
                unreachables_disable: true
              ipv6:
                enable: true
                addresses:
                  - address: 2001:db8:1::1
                    prefix_length: 64
                mtu: 1500
              service_policy_input:
                - name: QOS_IN
              service_policy_output:
                - name: QOS_OUT