ToR Peers

The tor_peers configuration enables you to define ToR (Top of Rack) switch pairings within your VXLAN EVPN fabric (iBGP and eBGP types of fabrics). ToR pairing establishes a parent-child relationship between leaf switches and ToR switches, with ToR switches connecting downstream to servers and upstream to leaf switches.

This feature requires NDFC 12.2.2.241+ and Nexus Dashboard 3.2.1i+ or later.

Diagram

Classes

topology (vxlan)

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

tor_peers (vxlan.topology)

Name	Type	Mandatory
pairing_id	String	No
parent_leaf1	String	Yes
parent_leaf2	String	No
tor1	String	Yes
tor2	String	No

Unsuported Scenarios

You cannot preprovision and pair ToR switch(es) with unavailable leaf switch(es). Both ToR and leaf switch(es) must be discovered by ND and be available.

Supported Scenarios

The feature supports three deployment scenarios:

Scenario	Description	Required Fields
vPC-to-vPC	Two ToR switches in vPC paired with two leaf switches in vPC	`tor1`, `tor2`, `parent_leaf1`, `parent_leaf2`
vPC-to-Standalone	Single ToR switch paired with two leaf switches in vPC	`tor1`, `parent_leaf1`, `parent_leaf2`
Standalone-to-Standalone	Single ToR switch paired with single leaf switch	`tor1`, `parent_leaf1`

Example 1 - vPC-to-vPC Pairing

This configuration pairs two ToR switches (ToR_24 and ToR_23) in a vPC domain with two leaf switches (LEAF_11 and LEAF_21) that are also in a vPC domain.

vxlan:
  topology:
    tor_peers:
      - tor1: ToR_24
        tor2: ToR_23
        parent_leaf1: LEAF_11
        parent_leaf2: LEAF_21

Example 2 - vPC-to-Standalone Pairing

This configuration pairs a single standalone ToR switch (ToR_31) with two leaf switches in a vPC domain.

vxlan:
  topology:
    tor_peers:
      - tor1: ToR_31
        parent_leaf1: LEAF_11
        parent_leaf2: LEAF_21

Example 3 - Standalone-to-Standalone Pairing

This configuration pairs a single ToR switch with a single leaf switch.

vxlan:
  topology:
    tor_peers:
      - tor1: ToR_13
        parent_leaf1: LEAF_14

Example 4 - Multiple ToR Pairings

You can define multiple ToR pairings in a single configuration file.

vxlan:
  topology:
    tor_peers:
      # vPC-to-vPC pairing
      - tor1: ToR_24
        tor2: ToR_23
        parent_leaf1: LEAF_11
        parent_leaf2: LEAF_21

      # vPC-to-Standalone pairing
      - tor1: ToR_31
        parent_leaf1: LEAF_11
        parent_leaf2: LEAF_21

      # Standalone-to-Standalone pairing
      - tor1: ToR_13
        parent_leaf1: LEAF_14

Prerequisites

Before configuring ToR pairing, ensure:

All ToR switches are defined in vxlan.topology.switches with role: tor
All leaf switches are defined in vxlan.topology.switches with role: leaf
For vPC scenarios, switches must be defined in vxlan.topology.vpc_peers
Switches must have a valid serial_number and be discovered (not in preprovision mode)

Network Attachments for ToR Switches

After pairing ToR switches, you can attach networks using network_attach_groups:

vxlan:
  overlay:
    network_attach_groups:
      - name: tor_networks
        switches:
          - hostname: ToR_23
            ports:
              - Port-channel555
              - Ethernet1/15
          - hostname: ToR_24
            ports:
              - Port-channel555
              - Ethernet1/15
          - hostname: ToR_31
            ports:
              - Ethernet1/13
          - hostname: ToR_13
            ports:
              - Ethernet1/13

Order of Operations

Adding ToR: First add to tor_peers, then add to network_attach_groups
Removing ToR: First remove from network_attach_groups, then remove from tor_peers

Enabling Removal Operations

By default, ToR pairing removal is disabled for safety. To enable automatic removal:

tor_pairing_delete_mode: true