Network attachment update: vlan field update need special payload

[mdmohan]

Looks like NDFC has a bug where it accepts vlan modification in attach payload only if following are present

  "switchPorts": "",
  "detachSwitchPorts": "",
  "torPorts": "",

Assuming these are not set.

Without these empty strings, NDFC fails with following error

{
    "path": "/rest/top-down/v2/fabrics/CML/networks/attachments",
    "Error": "Internal Server Error",
    "timestamp": "2025-12-17 12:22:10.052",
    "status": "500"
}

Bad PAyload: 500 Error

        "lanAttachList": [
            {
                "fabric": "CML",
                "networkName": "net_a_test_1",
                "serialNumber": "9Q34PHYLDB5",
                "deployment": "true",
                "vlan": "2456"
            },

Good Payload ->> 200 OK

  {
                "fabric": "CML",
                "networkName": "net_a_test_1",
                "serialNumber": "9CQ9P9E782H",
                "deployment": "true",
                "switchPorts": "",
                "detachSwitchPorts": "",
                "torPorts": "",
                "vlan": "2320"
  }