350-501 Practice Test 8 — 10 Questions

Question 1

A service provider is designing a QoS policy for a business VPN service that carries voice, video, and data. The policy must ensure that voice (EF) is never dropped even during congestion, while video (AF41) and data (AF21) share the remaining bandwidth in a ratio 2:1. Which queuing strategy should be used?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Apply LLQ for voice and CBWFQ for video and data with bandwidth ratio 2:1.. LLQ provides strict priority queuing for voice (EF), ensuring it is never dropped during congestion, while CBWFQ allows the remaining bandwidth to be shared among video (AF41) and data (AF21) in a 2:1 ratio. LLQ is designed to guarantee low latency for real-time traffic, and CBWFQ enables explicit bandwidth allocation for non-real-time classes. This combination meets the requirement of zero-drop for voice and proportional sharing for video and data.

Answer

Use only LLQ for all three classes.

Answer

Apply CBWFQ with bandwidth percentages to all three classes.

Answer

Use FIFO queuing with WRED for all classes.

Question 2

In the MQC (Modular QoS CLI) framework, which component is used to match traffic based on DSCP values?

Accepted Answer

Class-map. Class-maps define match criteria (e.g., match ip dscp 46) to classify traffic in MQC.

Answer

Service-policy

Answer

Access-list

Answer

Policy-map

Question 3

Which tool can verify connectivity along an MPLS Label Switched Path (LSP) and detect label loops?

Accepted Answer

MPLS LSP ping. MPLS LSP ping is the correct tool because it specifically tests connectivity along an MPLS Label Switched Path by sending MPLS echo request packets that follow the label stack, and it can detect label loops by checking the TTL field in the MPLS header. Unlike regular ICMP-based tools, MPLS LSP ping operates at the MPLS forwarding plane, verifying that the LSP is intact and that labels are correctly swapped at each hop.

Answer

SNMP

Answer

traceroute

Answer

ping

Question 4

A service provider is implementing QoS for voice traffic using the DiffServ model. Which DSCP value should be assigned to voice packets to ensure the highest priority treatment?

Accepted Answer

DSCP 46. DSCP 46 (binary 101110) corresponds to the Per-Hop Behavior (PHB) of Expedited Forwarding (EF), which is defined in RFC 3246 for low-loss, low-latency, and low-jitter treatment. Voice traffic requires the highest priority in a DiffServ domain, and EF (DSCP 46) is the standard marking for voice bearer packets to ensure they receive strict priority queuing.

Answer

DSCP 26

Answer

DSCP 34

Answer

DSCP 0

Question 5

An MPLS L3VPN service provider wants to prevent label spoofing attacks where a customer could inject MPLS labels to bypass ACLs. Which configuration practice should be implemented on PE-CE links?

Accepted Answer

Disable MPLS on PE-CE links. To prevent label spoofing attacks where a customer injects MPLS labels, the PE-CE link should not have MPLS enabled. Customer edge devices should not send labeled packets to the PE; disabling MPLS on PE-CE links ensures that any labeled packets from the customer are dropped or treated as IP, preventing label spoofing.

Answer

Enable MPLS TTL propagation to detect spoofing

Answer

Enable MPLS on PE-CE links with TTL propagation disabled

Answer

Use explicit null labels on PE-CE links

Question 6

A service provider is implementing network slicing for 5G services. Which of the following is NOT a typical characteristic of a network slice?

Accepted Answer

Slices require dedicated physical infrastructure per slice.. Network slicing in 5G is built on network function virtualization (NFV) and software-defined networking (SDN), allowing multiple logical networks to share the same physical infrastructure. Each slice is a virtualized, isolated instance with its own resources and performance characteristics, so requiring dedicated physical infrastructure per slice contradicts the fundamental efficiency and flexibility that slicing provides. Therefore, option C is NOT a typical characteristic.

Answer

Each slice can have its own dedicated virtualized functions and resources.

Answer

Slices can be customized for specific service types like eMBB, uRLLC, or mMTC.

Answer

Slices are isolated from each other in terms of performance and security.

Question 7

An operator notices that a new MPLS-TE tunnel is not being established. The tunnel configuration includes a dynamic path option and a bandwidth of 100 Mbps. The network uses RSVP-TE with CSPF. The link-state database shows sufficient reservable bandwidth on all links along the calculated path. What is the most likely cause of the tunnel establishment failure?

Accepted Answer

RSVP-TE is not enabled on the transit interfaces. RSVP-TE must be explicitly enabled on every interface that will participate in MPLS-TE label-switched path (LSP) signaling. Even if the link-state database shows sufficient reservable bandwidth, without RSVP-TE enabled on transit interfaces, the PATH messages cannot be processed, and the tunnel will fail to establish. This is a common misconfiguration when deploying MPLS-TE.

Answer

The path option is misconfigured with a strict explicit path

Answer

MPLS LDP is not enabled on the core routers

Answer

The tunnel source interface is not configured with an IP address

Question 8

A service provider is implementing MAP-T (Mapping of Address and Port using Translation) to transition customers from IPv4 to IPv6. Which two characteristics of MAP-T are true? (Choose two.)

Accepted Answer

MAP-T employs a Border Router that performs translation between IPv4 and IPv6. MAP-T uses stateful or stateless translation between IPv4 and IPv6, and it uses a Border Router (BR) that performs translation. MAP-T does not use encapsulation; it uses translation (NAT). MAP-T also uses a Domain Name System (DNS) but that is not unique. The key characteristics: it uses a BR for translation and can be stateless.

Answer

MAP-T is primarily used for IPv6-to-IPv4 communication only

Answer

MAP-T requires a dedicated IPv6 prefix for each customer

Answer

MAP-T uses encapsulation to transport IPv4 packets over an IPv6 network

Question 9

In IOS XR, which process is responsible for managing the configuration database and commit operations?

Accepted Answer

confd. In IOS XR, the confd process is responsible for managing the configuration database and commit operations. It handles configuration changes, validation, and commits, ensuring that the system configuration is consistent and applied atomically.

Answer

fman

Answer

sysmgr

Answer

rib

Question 10

Which MEF service type defines a point-to-point Ethernet connection, often used for business connectivity?

Accepted Answer

E-Line. E-Line is the MEF service type that defines a point-to-point Ethernet connection, providing a dedicated Ethernet Virtual Connection (EVC) between exactly two UNIs. It is the MEF equivalent of a point-to-point Ethernet private line and is commonly used for business connectivity such as site-to-site links and internet access. E-Line maps to services like Ethernet Private Line (EPL) and Ethernet Virtual Private Line (EVPL).

Answer

E-Tree

Answer

E-Access

Answer

E-LAN