The Virtualized Services Directory (VSD) contains an integrated certificate authority (CA) that is responsible for issuing digital certificates to all components within the Nuage Virtualized Services Platform (VSP). These certificates are used to establish secure, authenticated communication channels. The VSD CA enables TLS-secured communication between the VSC and VRS (OVSDB), between the NSG and VSC (XMPP), and is used to bootstrap IPsec tunnels between NSGs and VRSs. However, the communication between an NSG and the VSD is a direct client-server HTTPS connection. The VSD acts as the HTTPS server, not an intermediary proxy. Therefore, the statement that this communication is provided "by an HTTPS proxy" is architecturally incorrect.

B. This is a true statement. The VSD CA issues certificates to NSGs and VSCs to establish a mutually authenticated and encrypted XMPP over TLS session for control plane communication.

C. This is a true statement. The VSD CA issues certificates that are used by NSGs and VRSs to authenticate each other during the IKEv2 exchange, which establishes secure IPsec tunnels for data plane traffic.

D. This is a true statement. The VSD CA issues certificates to VSCs and VRSs to secure their OVSDB control channel using TLS, ensuring policy and forwarding rules are transmitted securely.

1. Nokia Nuage Networks Virtualized Services Platform Fundamentals Guide, Release 21.10.R1, Section: "VSP component communication", Document Part Number: 3HE 17489 AAAD TQZZA Edition 01.

This guide details the communication paths. It states, "The NSG first contacts the VSD to be authenticated and authorized... This is done over a secure HTTPS channel." This describes a direct connection, not one via a proxy, making option A incorrect. It also confirms VSC-VRS communication is OVSDB secured by TLS (Option D) and NSG-VSC is XMPP secured by TLS (Option B).

2. Nokia Nuage Networks Virtualized Services Platform Security Configuration Guide, Release 21.10.R1, Section: "VSP security model", Document Part Number: 3HE 17493 AAAD TQZZA Edition 01.

This document states, "The VSP security model uses a public key infrastructure (PKI) to authenticate the VSP components... The VSD acts as a Certificate Authority (CA) and generates certificates for all VSP components (VSC, VRS, NSG)." It further explains that these certificates are used for establishing IPsec tunnels, which validates the premise of Option C.