350-501 Architecture — Timed 50 Questions

Question 1

Which access technology is commonly used in service provider networks to deliver high-speed internet over existing telephone lines?

Accepted Answer

DSL. DSL (Digital Subscriber Line) uses existing telephone lines to provide high-speed internet access.

Answer

Metro Ethernet

Answer

GPON

Answer

Cable

Question 2

In IOS XR architecture, what is the role of the Secure Domain Router (SDR)?

Accepted Answer

It provides isolation for routing protocols and forwarding tables.. An SDR provides a logical partitioning of router resources, allowing multiple independent virtual routers within a single physical chassis.

Answer

It handles all packet forwarding in hardware.

Answer

It is used for OSPF only.

Answer

It manages the admin plane for all line cards.

Question 3

A service provider is deploying L3VPN using BGP/MPLS. Which mechanism ensures customer isolation in the provider network?

Accepted Answer

Virtual Routing and Forwarding (VRF). VRF (Virtual Routing and Forwarding) creates separate routing tables per customer, ensuring isolation.

Answer

Pseudowire

Answer

MP-BGP

Answer

MPLS labels

Question 4

Which Cisco router platform is designed for high-density 100GE and uses IOS XR, making it suitable for the core/backbone of a service provider network?

Accepted Answer

Cisco CRS. Cisco CRS (Carrier Routing System) is a high-end core router supporting high-density 100GE and running IOS XR.

Answer

Cisco NCS 5500

Answer

Cisco ASR 9000

Answer

Cisco ISR 4400

Question 5

In IOS XR, what is the commit/rollback configuration model?

Accepted Answer

Configuration changes are staged and committed atomically; rollback is supported.. The commit/rollback model applies changes atomically and allows reverting to previous configurations if needed.

Answer

It requires a reboot to apply changes.

Answer

Changes are applied immediately and cannot be undone.

Answer

It only applies to interface configurations.

Question 6

A service provider wants to provide point-to-point Ethernet services with strict SLAs. Which technology should they use?

Accepted Answer

VPWS. VPWS (Virtual Private Wire Service) or pseudowire provides a point-to-point Ethernet connection over MPLS.

Answer

EVPN

Answer

L3VPN

Answer

VPLS

Question 7

Which MEF service type provides a point-to-point Ethernet connection between two user-network interfaces (UNIs)?

Accepted Answer

E-Line. E-Line is the MEF service for point-to-point Ethernet connectivity.

Answer

E-LAN

Answer

E-Tree

Answer

E-Access

Question 8

What is the main benefit of using Q-in-Q (802.1ad) in metro Ethernet networks?

Accepted Answer

Increases the number of available VLANs. Q-in-Q allows multiple customer VLANs to be encapsulated within a service provider VLAN, increasing scalability.

Answer

Simplifies routing

Answer

Provides encryption

Answer

Reduces latency

Question 9

In EVPN, what is the function of the Ethernet Segment Identifier (ESI)?

Accepted Answer

It identifies a multi-homed device or network segment.. The ESI identifies a multi-homed device or network, enabling all-active redundancy and fast convergence.

Answer

It is used for load balancing among PEs.

Answer

It uniquely identifies a customer MAC address.

Answer

It identifies a VXLAN tunnel.

Question 10

A service provider is deploying network slicing for 5G services. Which slice type is characterized by low latency and high reliability for applications like autonomous driving?

Accepted Answer

uRLLC. uRLLC (Ultra-Reliable Low-Latency Communications) is designed for latency-critical and reliable applications.

Answer

FMC

Answer

eMBB

Answer

mMTC

Question 11

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

Accepted Answer

confd. The configuration management process handles commit/rollback and stores configuration in a database.

Answer

fman

Answer

sysmgr

Answer

rib

Question 12

A service provider is using NSO for service orchestration. Which protocol does NSO use to communicate with network devices for configuration?

Accepted Answer

NETCONF. NSO uses NETCONF as the primary protocol for device configuration, leveraging YANG models.

Answer

SNMP

Answer

RESTCONF

Answer

CLI scripting

Question 13

Which TWO are characteristics of the access layer in a service provider network? (Choose two.)

Accepted Answer

Provides connectivity to end customers. Access layer provides connectivity to end users and aggregates traffic from various technologies.

Answer

Implements inter-AS MPLS

Answer

Uses MPLS label switching for core traffic

Answer

Performs BGP route reflection

Question 14

Which TWO are benefits of using EVPN over traditional VPLS for L2VPN services? (Choose two.)

Accepted Answer

Provides MAC address learning via control plane. EVPN offers better control plane (BGP) and supports multi-homing with all-active load balancing.

Answer

Uses LDP for label distribution

Answer

Requires full mesh of pseudowires

Answer

Simpler configuration than VPLS

Question 15

Which THREE are correct statements about IOS XR process separation? (Choose three.)

Accepted Answer

Processes can be restarted independently without affecting others. IOS XR runs each protocol as a separate process, providing fault isolation and independent restart.

Answer

A failure in one process can crash the entire system

Answer

All processes share a single memory space

Question 16

Which access technology in a service provider network uses a passive optical splitter to distribute signals to multiple customers, with typical downstream speeds up to 2.5 Gbps?

Accepted Answer

GPON. GPON is a point-to-multipoint fiber access technology using passive optical splitters, providing downstream speeds up to 2.5 Gbps and upstream up to 1.25 Gbps.

Answer

Metro Ethernet

Answer

DSL

Answer

Cable (DOCSIS)

Question 17

An SP is deploying MPLS in the core/backbone to support L3VPN services. What is the purpose of MP-BGP in an MPLS VPN architecture?

Accepted Answer

To exchange customer VPN routes and VPN labels between PE routers. MP-BGP (Multiprotocol BGP) carries VPNv4 routes between PE routers, including the VPN label, enabling customer isolation and reachability across the MPLS core.

Answer

To forward data packets across the MPLS core

Answer

To establish IGP adjacencies between PE and CE routers

Answer

To distribute MPLS labels for LSPs

Question 18

An SP uses Cisco ASR 9000 routers with IOS XR. Which statement correctly describes the commit/rollback configuration model in IOS XR?

Accepted Answer

Changes are staged in a candidate configuration and applied only after 'commit'; rollback to a previous commit is possible.. IOS XR requires a 'commit' to apply changes; it supports rollback to previous committed configurations, allowing safe changes.

Answer

Only 'commit replace' is supported; rollback requires manual re-entry.

Answer

The router automatically commits changes every 10 minutes.

Answer

Changes take effect immediately without commit; rollback is not supported.

Question 19

Which Cisco router platform is designed for the core/backbone of a service provider network, supporting high-density 100GE interfaces and massive scale for MPLS and Segment Routing?

Accepted Answer

Cisco CRS. The Cisco CRS (Carrier Routing System) is a core router platform with high-density interfaces and large scale for MPLS and Segment Routing.

Answer

Cisco ASR 9000

Answer

Cisco ISR 4000

Answer

Cisco NCS 5500

Question 20

A service provider wants to offer a point-to-point Ethernet service between two customer sites with a defined bandwidth and performance guarantee, according to MEF standards. Which Carrier Ethernet service type is appropriate?

Accepted Answer

E-Line. E-Line (Ethernet Line) is a point-to-point service defined by MEF for Carrier Ethernet.

Answer

E-LAN

Answer

E-Access

Answer

E-Tree