fix: send default OSPF auth key ID (127) when authentication is disabled

[ccoueffe]

Fixes #869

Related Collection Role

• cisco.nac_dc_vxlan.validate
• cisco.nac_dc_vxlan.dtc.create
• cisco.nac_dc_vxlan.dtc.deploy
• cisco.nac_dc_vxlan.dtc.remove
• other

Related Data Model Element

• vxlan.fabric
• vxlan.global
• vxlan.topology
• vxlan.underlay
• vxlan.overlay
• vxlan.overlay_extensions
• vxlan.policy
• vxlan.multisite
• defaults.vxlan
• other

Proposed Changes

When ospf.authentication_enable: false, NDFC rejects any OSPF_AUTH_KEY_ID value other than empty or 127. Previously the template always sent the user-provided key ID, causing fabric update failures when auth was disabled but a key ID was defined in the data model.

Template fix (dc_vxlan_fabric_protocols.j2)

Condition	Before	After
authentication_enable: true	Sends user key ID + key	Sends user key ID + key (unchanged)
authentication_enable: false	Sends user key ID (fails if != 127)	Sends default key ID (127 from defaults)

The else branch now explicitly sends the default OSPF_AUTH_KEY_ID (127) when authentication is disabled. This is safe because:

• 127 is the NDFC default value for OSPF_AUTH_KEY_ID in the dcnm_fabric module
• 127 is accepted by NDFC in all scenarios (fresh fabric, previously enabled then disabled)
• OSPF_AUTH_KEY is not sent when auth is disabled (omitted from payload)

Data Model Example

vxlan:
  underlay:
    ospf:
      area_id: 0.0.0.0
      authentication_enable: false    # auth disabled
      authentication_key_id: 10       # ignored — template sends 127 instead
      authentication_key: my_key      # ignored — not sent to NDFC

Test Notes

Tested with:

• Fresh fabric with auth disabled → ✅ deploys cleanly
• Fabric with auth previously enabled then disabled → ✅ OSPF_AUTH_KEY_ID=127 accepted
• Fabric with auth enabled → ✅ user key ID sent as before

Cisco Nexus Dashboard Version

12.4.1

Checklist

• Latest commit is rebased from develop with merge conflicts resolved
• New or updates to documentation has been made accordingly
• Assigned the proper reviewers