Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


Create a Layer 3 Fabric based Underlay Network


Layer 3 Fabrics based on multi-stage Clos architecture increases resiliency and also supports new technologies such as VMware NSX that allow enterprises to deploy applications, servers, and virtual networks within seconds. The Layer 3 Fabrics can also function as an underlay network for a EVPN—VXLAN based overlay networks. Layer 3 Fabrics use BGP as the control plane protocol to advertise prefixes, perform traffic engineering, and tag traffic. Layer 3 Fabric uses spine-and-leaf topology. In the spine-and-leaf topology, all the leaf devices are connected to the spine devices in a mesh.

You can use one of the following device models as the spine device in a Layer 3 Fabric:

  • QFX10008

  • QFX10002-36Q

  • QFX10002-72Q

  • QFX5100-24Q-2P

  • QFX5200-32C-32Q

You can use the following device models as leaf devices:

  • QFX5100-48S-6Q

  • QFX5100-96S-8Q

  • QFX5100-48T-6Q

  • QFX5200-32C-32Q

  • QFX5100-24Q

  • QFX5100-24Q-2P


QFX5100-48T-6Q, QFX5100-48S-6Q and QFX5100-96S-8Q can be standalone or Virtual Chassis leaf devices. Whereas, QFX10008 and QFX5100-24Q are supported only as standalone devices. QFX5200-32C-32Q can be supported as both spine and leaf device, however, it cannot be a Virtual Chassis member.

You can quickly create and deploy Layer 3 Fabrics by using Network Director.

Before you begin, ensure that you have the necessary privileges on the FTP and the file server that Network Director uses for Zero Touch Provisioning. For more details, see User Privileges Required for the DHCP and File Server While Using Zero Touch Provisioning.

To create and deploy a Layer 3 Fabric using Network Director:

  1. With Build mode or Deploy mode selected, select one of these options under Views: Logical View, Location View, Device View, or Custom Group View.
  2. In the Tasks pane, click Network Builder > Manage Layer 3 Fabrics.

    The Manage Layer 3 Fabrics page opens.

  3. Click Create to create a new Layer 3 Fabric. Table 1 describes the various pages that are available in the Layer 3 Fabric wizard and the actions that you must perform on each page.

    Table 1: Layer 3 Fabric Wizard Pages

    Name of the wizard page


    Fabric Requirements

    Specify the fabric name, spine and leaf device models, number of spine and leaf devices, and settings for dynamic host link aggregation group (LAG) creation.

    Device Details

    Displays the number of spine and leaf devices that you are provisioning as part of the initial capacity, enables you to edit the hostname prefix for all the spine and leaf devices.


    Specify the configuration details such as the Loopback Network Address, Interconnect Network Address, VLAN Network Address, Start Management IP, Maximum Hosts or VMs per leaf, Spine-BGP Autonomous System Number, Leaf-BGP Autonomous System Number, Device Password, and Management Gateway IP address.


    Displays the recommended cabling plan for the device that you select in the left pane. If you specify all the spine and leaf devices, the cabling plan displays the exact port numbers that you must use to connect your spine and leaf devices. However, if you have not specified any leaf devices and have specified only the maximum leaf count, the plan displays all the leaf devices as unknown. The leaf devices in this case are plug-and-play and you can use any of the uplink ports on the leaf devices.

    You must follow the cabling plan for all the physical connections between the spine and leaf devices in your fabric.


    Zero Touch Provisioning (ZTP) enables you to provision devices in your network automatically, without manual intervention. You can use the ZTP wizard page that is part of the Layer 3 Fabric wizard. When a device is physically connected, it boots up with the factory-default configuration and auto installs a configuration file from the network. In Network Director, ZTP is used to provision Layer 3 Fabrics and all the configurations are pushed through OpenClos.

    Note: When you select QFX10008 as the spine device, only the leaf devices in the fabric are provisioned using ZTP. For the QFX10008 spine device, you must either copy the configuration file from Network Director or manually download it from the file server. To copy the configuration file from the file server, SSH or Telnet must be enabled on the device (QFX10008).


    Review the Layer 3 Fabric configuration, deploy the fabric, or save and close the Layer 3 Fabric wizard.

    For detailed steps for creating the Layer 3 Fabric, see Creating Layer 3 Fabrics.

  4. After you have deployed the Layer 3 Fabric, you can run connectivity checks to troubleshoot any connectivity issues in the fabric. You can initiate a connectivity check by clicking Run Connectivity Check or Re-run Connectivity Check in the Cabling column in the Manage Layer 3 Fabrics page.

    Network Director uses LLDP to check the connectivity of each device with the device’s neighbor and compares it with the recommended cabling plan and reports the results in the Cabling Check Results page. For more details, see Performing Layer 3 Fabric Connectivity Checks.

  5. Click View Topology in the Summary column of the Manage Layer 3 Fabric page to view the physical topology of the Layer 3 Fabric.
  6. After you have successfully deployed a Layer 3 Fabric, you can monitor the performance, identify errors or bottlenecks in your underlay network by using the Monitoring mode of Network Director. For details, see Status Monitor for Layer 3 Fabrics and Port Status for IP Fabric Monitor.