Create an IP Subnetwork record

  • Release version: Australia
  • Updated June 16, 2026
  • 3 minutes to read

    • Create an IP Subnetwork record to subdivide an IP Address Block or to nest a subnetwork within an existing IP Subnetwork. The subnetwork’s CIDR must fall within its parent’s range. Supports both IPv4 and IPv6.

    Before you begin

    Before you begin:

    • Install all required Modeling your workflow plugins.
    • Role required: core.dc_ops_agent, sn_ni_core.inventory_agent
    • The parent IP Address Block or IP Subnetwork must be in an active state (Life Cycle Stage = Operational and Life Cycle Stage Status = In Use).

    About this task

    When you create an IP Subnetwork record, the system creates a corresponding configuration item (CI) record in the IP Network Subnet (cmdb_ci_ip_network_subnet) table.

    An IP Subnetwork can itself contain further nested IP Subnetworks. The nesting depth is not limited. To create a nested subnetwork, follow this procedure but start from the parent IP Subnetwork’s record rather than from the IP Address Block.

    The IP Subnetwork label in the user interface refers to the Managed IP Network Subnet class in the underlying data model.

    Procedure

    1. Navigate to Workspaces > Network Inventory Workspace or Service Operations Workspace.
    2. Open the parent record under which you want to create the subnetwork:
      • To create a top-level subnetwork, open an IP Address Block record (Inventory Number Allocation > IP Address Block > select the block).
      • To create a nested subnetwork, open an IP Subnetwork record (Inventory Number Allocation > IP Network Subnets > select the subnetwork).
    3. Select the IP Subnetwork tab (for top-level subnetworks) or the Nested IP Subnet tab (for nested subnetworks).
    4. Select Create IP Subnetwork.
    5. On the Create Nested IP Subnetwork form, fill in the fields:
      Field Description Required
      Nested Pool Name Enter a name for this subnetwork. Yes
      CIDR The subnetwork’s address range in CIDR notation. The CIDR must be a more-specific range within the parent’s CIDR. The system validates the CIDR on save. To learn more, see CIDR validation rules for IP Address Blocks and IP Subnetworks. Yes
      Managed Network Inherited from the parent. If the parent has a Managed Network set, this field is read-only and pre-populated with the parent’s value. If the parent has no Managed Network, this field is editable. To learn more, see Managed Network form. Conditional
      Parent Pool The parent record. Read-only
      DNS Domain The DNS domain for this subnetwork. No
      Description Description of the subnetwork. No
      Life cycle stage The current lifecycle stage. Default: Operational. No
      Life Cycle Stage Status The current lifecycle status. Default: In Use. The subnetwork must be Operational and In Use to support nested subnetworks and IP allocations. No
    6. Select Submit.

      If the CIDR fails validation, an inline error message is displayed. Common rejections include the CIDR falling outside the parent’s range, the CIDR being identical to the parent, and the CIDR duplicating another subnetwork under the same parent. To learn more about the validation rules, see CIDR validation rules for IP Address Blocks and IP Subnetworks. On successful submission, the system navigates to the new IP Subnetwork record.

    7. To create the Modeling your workflow attributes for this IP Subnetwork, select Set Inventory Attributes.

      When you select Set Inventory Attributes, the system creates a TNI CI Attributes record in the CI table and in the Modeling your workflow CI Attributes tables, and links it to the CI record.

      Note:
      If you select Save without selecting Set Inventory Attributes, the system creates a CI record but not a Modeling your workflow CI record. In the Network Inventory Workspace, Set Inventory Attributes is visible only for Modeling your workflow roles. In the TNI CI attributes form, the name is fetched from the Name field by default, and the Inventory Category is set as IP Address.
    8. To add packs to this service, select Add Packs.
    9. To add attachments such as graphics or documents, select the attachment icon in the right panel.
    10. View the hierarchy of records under this subnetwork by selecting the Dependency View option from the three-dot menu.
    11. View the related network inventories by selecting the brick icon.

      The Infrastructure Relationships section shows all the related network inventories grouped by the individual network instance.

    What to do next

    Allocate IP address slots from this subnetwork to begin managing individual addresses, or create a single IP Address record representing the subnetwork as a whole:

    You can also review or update the fields, create a related tab record, or delete a record. To learn more, see Update or delete a record of an inventory number allocation .