350-501 Practice Test 6 — 10 Questions

Question 1

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 2

Which MEF Carrier Ethernet service type is used for a rooted-multipoint topology, where a single root site communicates with multiple leaf sites but leaf sites cannot communicate directly?

Accepted Answer

E-Tree. E-Tree (Ethernet Tree) is a rooted-multipoint service where the root can communicate with leaves, but leaves cannot communicate with each other.

Answer

E-Access

Answer

E-LAN

Answer

E-Line

Question 3

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 4

Which THREE of the following are benefits of using EVPN over traditional VPLS for L2VPN services? (Select three.)

Accepted Answer

Integrated L2 and L3 services (e.g., IRB). EVPN offers BGP control plane, multi-homing with ESI, and integrated L2/L3 services.

Answer

Supports only point-to-point pseudowires

Answer

Eliminates the need for VPLS

Question 5

Which architecture feature of IOS XR ensures that a failure in one routing protocol process does not affect other processes on the same router?

Accepted Answer

Process separation with each protocol as a separate process. IOS XR's process separation model runs each routing protocol as an independent process with its own protected memory space. If one protocol process fails (e.g., OSPF crashes), the other processes (BGP, ISIS) continue running unaffected, providing fault isolation and preventing a single protocol failure from cascading across the router.

Answer

Admin plane vs default SDR

Answer

Commit/rollback configuration model

Answer

CPU and memory allocation per card

Question 6

Which MEF service type is used for multipoint-to-multipoint Ethernet connectivity, such as a corporate LAN extension across multiple sites?

Accepted Answer

E-LAN. E-LAN (Ethernet LAN) is the MEF service type that provides multipoint-to-multipoint Ethernet connectivity, allowing any site to communicate with any other site as if they were on the same LAN. It is the standard choice for corporate LAN extension across multiple locations. E-Line is point-to-point and E-Tree is rooted multipoint, so neither matches the multipoint-to-multipoint requirement.

Answer

E-Line

Answer

E-Tree

Answer

E-Access

Question 7

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 uses a two-stage configuration model: changes are made in a candidate configuration and only take effect after the 'commit' command. The system maintains a rollback buffer of previous commits, allowing rollback to any of the last 10 committed configurations using 'rollback configuration' or 'load rollback changes'. This provides safe, transactional configuration 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 8

An SP network uses OSPF with RSVP-TE for traffic engineering. Which OSPF extension is required to advertise TE link parameters such as maximum reservable bandwidth?

Accepted Answer

OSPF Type 10 Opaque LSAs. OSPF TE extensions are defined in RFC 3630, which introduces the Opaque LSA (Type 9, 10, 11). Specifically, Type 10 Opaque LSAs carry TE information. The TE LSA is carried in an Opaque LSA of area scope (Type 10).

Answer

OSPF Type 7 LSAs

Answer

OSPF Type 11 Opaque LSAs

Answer

OSPF Type 5 LSAs

Question 9

A service provider wants to automate service provisioning using NSO. Which protocol is typically used by NSO to configure network devices?

Accepted Answer

NETCONF. Cisco NSO (Network Services Orchestrator) uses NETCONF as its primary southbound protocol to configure network devices, leveraging YANG data models for structured, transactional configuration. NETCONF's candidate/commit model aligns with NSO's intent-based automation approach.

Answer

CLI scripting

Answer

SNMP

Answer

RESTCONF

Question 10

An SP uses SR-PCE for traffic engineering. Which protocol does the SR-PCE use to communicate path computation requests and responses with path computation clients (PCCs)?

Accepted Answer

PCEP. PCEP (Path Computation Element Protocol) is used between PCCs (e.g., routers) and a PCE (e.g., SR-PCE) for path computation requests and responses.

Answer

BGP-LS

Answer

NETCONF

Answer

RESTCONF