The Versa Networks SD-WAN control plane is fundamentally built on Multi-Protocol BGP (MP-BGP). The Versa Controllers act as route reflectors, and the branch appliances (FlexVNFs/CSGs) establish internal BGP (iBGP) peerings with them. This MP-iBGP framework is used to discover and maintain the SD-WAN topology.

To transport SD-WAN-specific overlay information—such as Transport Locators (TLOCs), encryption keys, and site IDs—Versa utilizes a proprietary BGP address family. This allows the standard BGP protocol to carry the necessary custom information required to build the SD-WAN fabric, effectively using a "Private Address Family" for topology advertisement.

A. SD-WAN topology is discovered using eBGP.

The relationship between branch appliances and controllers is within a single autonomous system, mandating the use of internal BGP (iBGP), not external BGP (eBGP).

D. NETCONF advertises topology changes.

NETCONF is a management plane protocol used by Versa Director to push configuration to devices. It does not dynamically advertise topology changes; that is the role of the control plane protocol, MP-BGP.

1. Versa Networks

"Versa Operating System (VOS™) 21.2.2 SD-WAN and SASE Configuration Guide

" Chapter: BGP for SD-WAN

Section: "BGP for SD-WAN Overview." This section states

"The Versa solution uses Multi-Protocol BGP (MP-BGP) as the control plane protocol to exchange reachability information between the branch CPEs and the controllers... The peering between the CPEs and the controllers is an iBGP peering." This supports option B and refutes option A.

2. Versa Networks

"Versa Operating System (VOS™) 21.2.2 SD-WAN and SASE Configuration Guide

" Chapter: BGP for SD-WAN

Section: "SD-WAN Routes." This section details the use of a specific address family for SD-WAN routes: "Versa Networks uses a proprietary BGP address family to exchange SD-WAN-specific information... The address family is SD-WAN (AFI 16396

SAFI 254)." This directly supports option C.

3. Versa Networks

"Versa Director Configuration and Administration Guide 21.2.2

" Chapter: Versa Director Overview

Section: "Versa Director Architecture." This document clarifies the role of NETCONF: "Versa Director uses the NETCONF protocol to configure and manage the Versa devices (Controllers

Analytics

and FlexVNFs)." This confirms NETCONF is for management

refuting its role in advertising topology changes as suggested in option D.