350-501 Networking Practice Test 12 — 15 Questions

Question 1

Which OSPF area type can import external routes as Type 7 LSAs?

Accepted Answer

NSSA. NSSA (Not-So-Stubby Area) allows the import of external routes as Type 7 LSAs, which are translated to Type 5 at the ABR.

Answer

Stub area

Answer

Standard area

Answer

Totally stubby

Question 2

A service provider is designing an OSPF network with multiple areas. Which two area types prevent Type 5 LSAs from being flooded? (Choose two.)

Accepted Answer

Stub area. Stub and NSSA areas both block Type 5 LSAs; totally stubby also blocks Type 3/4.

Answer

Standard area

Answer

Totally stubby area

Answer

Backbone area

Question 3

Which three BGP attributes are considered during the route selection process before comparing AS_PATH length? (Choose three.)

Accepted Answer

LOCAL_PREF. Weight, LOCAL_PREF, and locally originated routes are compared before AS_PATH length in the BGP best path selection algorithm.

Answer

NEXT_HOP

Answer

MED

Question 4

A service provider is deploying IPv6 transition mechanisms. Which three technologies use encapsulation over an IPv4 network? (Choose three.)

Accepted Answer

6VPE. 6PE, 6VPE, and 6rd encapsulate IPv6 packets over IPv4; MAP-T uses translation, not encapsulation.

Answer

NAT64

Answer

MAP-T

Question 5

In IS-IS, which type of router is responsible for exchanging routing information between different areas?

Accepted Answer

L2 router. L2 routers handle inter-area routing in IS-IS, while L1 routers handle intra-area routing. L1/L2 routers act as both.

Answer

L1/L2 router

Answer

L1 router

Answer

Attached router

Question 6

An SP network is migrating from IS-IS narrow metrics to wide metrics. What is a key advantage of using wide metrics?

Accepted Answer

Wide metrics support up to 2^24-1 link cost and TE metrics.. Wide metrics support values up to 2^24-1 (16,777,215) and allow Traffic Engineering (TE) metrics, unlike narrow metrics which are limited to 6 bits (max 63).

Answer

Wide metrics are backward compatible with narrow metrics without any configuration.

Answer

Wide metrics reduce SPF computation time.

Answer

Wide metrics enable BFD for faster convergence.

Question 7

In OSPFv3 (for IPv6), which of the following statements is true regarding OSPFv3 packet format and authentication?

Accepted Answer

OSPFv3 relies on IPsec for authentication and encryption.. OSPFv3 uses IPsec for authentication and does not include authentication fields in the OSPF header. It runs per-link instead of per-subnet.

Answer

OSPFv3 does not support authentication.

Answer

OSPFv3 authenticates using the Authentication field in the OSPF header.

Answer

OSPFv3 uses the same authentication mechanisms as OSPFv2.

Question 8

In BGP route selection, if two routes have the same weight, local preference, and are both locally originated, which attribute is considered next?

Accepted Answer

AS_PATH length. After weight, local pref, and locally originated, BGP compares AS_PATH length (shorter is preferred).

Answer

ORIGIN code

Answer

NEXT_HOP metric

Answer

MED

Question 9

A service provider is implementing BGP PIC (Prefix Independent Convergence) for its core network. Which mechanism does BGP PIC primarily rely on to achieve fast convergence?

Accepted Answer

Precomputed backup paths (BGP PIC edge). BGP PIC uses precomputed backup paths (e.g., via BGP PIC edge or BGP add-path) to switch traffic upon failure without waiting for BGP convergence.

Answer

BFD

Answer

Route reflectors

Answer

Communities

Question 10

In IS-IS, what is the purpose of the NET (Network Entity Title) address field SEL (Selector) byte?

Accepted Answer

Indicates that this is a router (always 0x00). The SEL byte is always 0x00 for routers, indicating that the address refers to the router itself rather than a specific service.

Answer

Identifies the application layer protocol

Answer

Identifies the area

Answer

Identifies the system ID

Question 11

Which OSPF area type is most suitable for a service provider's customer-facing network where external routes are blocked, but internal routes (including inter-area) are allowed, and the area should not accept Type 5 LSAs?

Accepted Answer

Stub area. A stub area blocks Type 5 LSAs but allows inter-area and intra-area routes. It injects a default route. NSSA allows limited external routes via Type 7, which is not desired here.

Answer

NSSA

Answer

Backbone area

Answer

Totally stubby area

Question 12

In BGP, what is the purpose of the ORIGINATOR_ID attribute in a route reflector environment?

Accepted Answer

Identifies the originating router to prevent loops. ORIGINATOR_ID is set by the route reflector to identify the originator of the route. It is used to prevent loops in iBGP.

Answer

Indicates the next-hop router

Answer

Sets the local preference

Answer

Identifies the route reflector cluster

Question 13

Which technology allows an IPv6-only customer edge router to connect to an MPLS provider edge router using IPv4 transport, encapsulating IPv6 packets in MPLS with a labeled IPv4 next-hop?

Accepted Answer

6PE. 6PE (IPv6 Provider Edge) uses MP-BGP to exchange IPv6 prefixes with IPv4 next-hop addresses over MPLS. It does not require IPv6 in the core.

Answer

6VPE

Answer

NAT64

Answer

MAP-T

Question 14

An engineer is configuring IS-IS fast convergence. Which mechanism provides sub-second failure detection independently of the routing protocol?

Accepted Answer

BFD. BFD (Bidirectional Forwarding Detection) provides fast failure detection at the link layer, triggering routing protocol convergence.

Answer

LSP fast flooding

Answer

PRC (Partial Route Computation)

Answer

iSPF (incremental SPF)

Question 15

In OSPF TE extensions for RSVP-TE, which LSA type is used to carry TE information (such as link attributes) in OSPF?

Accepted Answer

Type 10 Opaque LSA. Opaque LSA Type 10 (Area-local) is used for TE information in OSPF. Type 9 is link-local, Type 11 is AS-scoped.

Answer

Type 11 Opaque LSA

Answer

Type 5 AS-external LSA

Answer

Type 9 Opaque LSA