Cisco 350-401 Questions Answers

The correct answer is B. TLS.

In Cisco Catalyst SD-WAN, the architecture separates:

Control Plane → Secure communication between controllers and edge devices

Data Plane → Encrypted tunnels carrying user traffic

The control plane (between vSmart, vBond, vManage, and WAN Edge routers) uses:

TLS (Transport Layer Security)

In some cases also DTLS, depending on configuration

These protocols provide:

Authentication

Encryption

Integrity protection

Thus, TLS is used to establish secure control plane adjacencies.

A. IPsec Used for data plane encryption (IPsec tunnels), not control plane.

C. IKE Used for key exchange in IPsec, not for SD-WAN control plane adjacencies.

D. ESP Part of IPsec (data plane encryption), not control plane.

Memorize this SD-WAN separation:

Control Plane → TLS / DTLS

Data Plane → IPsec (ESP encapsulation)

This distinction is frequently tested in ENCOR exams.

The correct answer is B. TLS or SSL for communication.

In basic API authentication, credentials (such as username and password) are often transmitted using Base64 encoding, which is not encrypted. This makes them vulnerable to sniffer (packet capture) attacks if sent over an unencrypted channel.

TLS (Transport Layer Security) and its predecessor SSL provide encryption of the communication channel.

This ensures that even if packets are captured, the credentials remain confidential and unreadable.

Cisco documentation emphasizes that APIs (RESTCONF, HTTP-based APIs) should use HTTPS (HTTP over TLS) to secure credentials in transit.

A. VPN connection between client and server While a VPN encrypts traffic, it is not specifically required for API authentication security. The standard and expected method is TLS/HTTPS.

C. AAA services to authenticate the API AAA controls who can access, but it does not encrypt credentials in transit.

D. next-generation firewall A firewall provides traffic filtering and threat protection but does not directly secure credential transmission in basic API authentication.

Basic Authentication = NOT secure by itself

Always pair it with HTTPS (TLS encryption)

Rule to remember:

If credentials travel over the network → encrypt with TLS