Fabric Link

Diagram

Classes

topology (vxlan)

Name	Type	Constraint	Mandatory	Default Value
fabric_links	List	`[fabric_links]`	No

fabric_links (vxlan.topology)

Name	Type	Constraint	Mandatory	Default Value
source_device	String		Yes
source_interface	String	Regex: `(?i)^(?:e\|eth(?:ernet)?)\d(?:\/\d+){1,2}\|vlan(?:[1-9]\|[1-9]\d{1,2}\|[1-3]\d{3}\|40[0-8]\|409[0-4]:?)$`	Yes
source_description	String		No
dest_device	String		Yes
dest_interface	String	Regex: `(?i)^(?:e\|eth(?:ernet)?)\d(?:\/\d+){1,2}\|vlan(?:[1-9]\|[1-9]\d{1,2}\|[1-3]\d{3}\|40[0-8]\|409[0-4]:?)$`	Yes
destination_description	String		No
template	String		No
admin_state	Boolean	`true`, `false`	No	`true`
mtu	Integer	min: `1500`, max: `9216`	No	`9216`
ipv4	Class	`[ipv4]`	No

ipv4 (vxlan.topology.fabric_links)

Name	Type	Mandatory
subnet	IP	Yes
source_ipv4	IP	Yes
dest_ipv4	IP	Yes

Example 1

You can add links between border switches of different fabrics (inter-fabric links) or between switches in the same fabric (intra-fabric links). You can only create an inter-fabric connection (IFC) for a switch that is managed by Nexus Dashboard Fabric Controller.

There are scenarios where you might want to define links between switches before connecting them physically. The links could be inter-fabric or intra-fabric links. Doing so, you can express and represent your intent to add links. The links with intent are displayed in a different color till they are actually converted to functional links. Once you physically connect the links, they are displayed as connected.

In this scenario, we will establish two fabric links: the first link connects dc1-leaf1 to dc1-spine1, and the second link connects dc1-leaf1 to dc1-spine2. Both links will utilize the template named int_pre_provision_intra_fabric_link.

This configuration defines two intra-fabric links using the specified template, which is intended for IP unnumbered interfaces between fabric switches. After saving and deploying this configuration, IP addresses will be automatically assigned from the underlay subnet pool, and the links will be reflected in the fabric topology.

You can choose any of the following link templates:

int_intra_fabric_num_link: If the link is between two ethernet interfaces assigned with IP addresses, choose int_intra_fabric_num_link.
int_intra_fabric_unnum_link: If the link is between two IP unnumbered interfaces, choose int_intra_fabric_unnum_link.
int_intra_vpc_peer_keep_alive_link: If the link is a vPC peer keep-alive link, choose int_intra_vpc_peer_keep_alive_link.
int_pre_provision_intra_fabric_link: If the link is between two pre-provisioned devices, choose int_pre_provision_intra_fabric_link. After you click Save & Deploy, an IP address is picked from the underlay subnet IP pool.

vxlan:
  topology:
    fabric_links:
      - source_device: dc1-leaf1
        source_interface: eth1/49
        dest_device: dc1-spine1
        dest_interface: eth1/1
        template: int_pre_provision_intra_fabric_link
        source_description: "dc1-leaf1 eth1/49 to dc1-spine1 eth1/1"
        destination_description: "dc1-spine1 eth1/1 to dc1-leaf1 eth1/49"
      - source_device: dc1-leaf1
        source_interface: eth1/50
        dest_device: dc1-spine2
        dest_interface: eth1/1
        template: int_pre_provision_intra_fabric_link

More detail in NDFC: https://www.cisco.com/c/en/us/td/docs/dcn/ndfc/1213/articles/ndfc-about-fabric-overview-for-lan-operational-mode-setups/about-fabric-overview-for-lan-operational-mode-setups.html#_links

Example 2

In this scenario, the following configuration is used to assign IP addresses on point-to-point links or backup links in a vPC environment. This option is available only when you choose to manually assign IP addresses by setting the parameter vxlan.underlay.general.manual_underlay_allocation to True.

The example allocates the subnet 10.5.0.0/31, assigning IP address 10.5.0.0/31 to dc1-leaf1 and 10.5.0.1/31 to dc1-leaf2. These IP addresses are configured on the SVI interface 3600, which is the default interface and can be modified using the key vxlan.global.vpc.peer_link_vlan. This example applies when the underlay is configured as point-to-point (p2p) or unnumbered, since unnumbered interfaces are not supported on SVIs.

The second part of the example allocates the subnet 10.4.0.0/31, assigning IP address 10.4.0.0/31 to dc1-leaf1 Ethernet E1/49 and 10.4.0.1/31 to dc1-spine1 Ethernet1/1. In this case underlay in vxlan.underlay.ipv4 must be in p2p.

vxlan:
  topology:
    fabric_links:
      # Backup link over peer-link for the underlay
      - source_device: dc1-leaf1
        source_interface: Vlan3600
        dest_device: dc1-leaf2
        dest_interface: Vlan3600
        ipv4:
          subnet: 10.5.0.0/31
          source_ipv4: 10.5.0.0
          dest_ipv4: 10.5.0.1

      # Example of P2P w/ physical interfaces
      - source_device: dc1-leaf1
        source_interface: eth1/49
        dest_device: dc1-spine1
        dest_interface: eth1/1
        ipv4:
          subnet: 10.4.0.0/31
          source_ipv4: 10.4.0.0
          dest_ipv4: 10.4.0.1