350-501 Networking — Timed 10 Questions

Question 1

An SP engineer is configuring IS-IS on a router and specifies a NET address of 49.0001.1921.6800.1001.00. What does the '00' at the end represent?

Accepted Answer

SEL (NSAP Selector). The last two octets of an IS-IS NET address represent the SEL (NSAP Selector), which is always 00 for a router.

Answer

AFI

Answer

System ID

Answer

Area ID

Question 2

In an OSPF network, an engineer wants to minimize the size of the routing table in a non-backbone area while still allowing the area to learn external routes from other ASs. Which OSPF area type should be configured?

Accepted Answer

NSSA. A Not-So-Stubby Area (NSSA) allows importing external routes as Type 7 LSAs while still blocking Type 5 LSAs from other areas.

Answer

Stub area

Answer

Totally stubby area

Answer

Backbone area 0

Question 3

Which BGP attribute is NOT considered in the BGP best path selection process when all other attributes are equal and the routes are from different ASs?

Accepted Answer

MED. Weight is Cisco-specific and considered first, but it is not a standard BGP attribute; it is considered before LOCAL_PREF.

Answer

LOCAL_PREF

Answer

AS_PATH length

Answer

Weight

Question 4

An SP network uses MPLS to provide IPv6 connectivity over an IPv4 backbone using 6PE. Which BGP extension is required on the provider edge routers to exchange IPv6 prefixes with an IPv4 next-hop?

Accepted Answer

BGP multiprotocol extensions (MP-BGP) with IPv6 address family. 6PE uses BGP multiprotocol extensions (MP-BGP) with an AFI of 2 (IPv6) and SAFI of 1 (unicast), and the next-hop is encoded as an IPv4 address using the 'next-hop' attribute.

Answer

BGP route reflection

Answer

BGP confederation

Answer

BGP prefix-independent convergence (PIC)

Question 5

In IS-IS, which type of LSP is used to advertise prefix information for IPv4 and IPv6 in a modern SP network that supports traffic engineering?

Accepted Answer

TLV 135 (Extended IP Reachability). TLV 135 for IPv4 (extended IP reachability) and TLV 236 for IPv6 (IPv6 reachability) are used in IS-IS for prefix advertisement.

Answer

TLV 2 (IS Neighbors)

Answer

TLV 1 (Area Addresses)

Answer

TLV 22 (IS Extended Neighbors)

Question 6

An OSPF network is configured with RSVP-TE. Which OSPF extension is used to advertise TE link attributes such as bandwidth and administrative group?

Accepted Answer

OSPF Type 10 Opaque LSA. OSPF TE extensions use Opaque LSAs (Type 9, 10, 11) to carry TE information. Type 10 (area-local) is commonly used for TE.

Answer

OSPF Type 1 LSA

Answer

OSPF Type 5 LSA

Answer

OSPF Type 7 LSA

Question 7

In BGP route reflection, what is the purpose of the ORIGINATOR_ID attribute?

Accepted Answer

To prevent routing loops by ensuring that a route is not reflected back to its originator. ORIGINATOR_ID is a non-transitive optional attribute that identifies the router that originated the route into the iBGP domain, used to prevent loops.

Answer

To indicate the next-hop IP address

Answer

To identify the route reflector

Answer

To carry the community value

Question 8

An SP is implementing IPv6 transition using MAP-T. Which encapsulation method does MAP-T use?

Accepted Answer

IPv4-IPv6 translation (NAT64-like). MAP-T (Mapping of Address and Port using Translation) uses IPv4-IPv6 translation (stateless NAT64-like) at the customer edge, not encapsulation.

Answer

MPLS label switching

Answer

IPv4 in IPv6 encapsulation

Answer

IPv6 in IPv4 encapsulation

Question 9

In IS-IS, which metric type supports traffic engineering (TE) and is required for segment routing?

Accepted Answer

Wide metrics (TLV 135/236/22). IS-IS wide metrics (TLV 135/236/22) support TE and segment routing; narrow metrics (TLV 128/130) are limited to 6-bit metrics.

Answer

Default metric (TLV 2)

Answer

Narrow metrics (TLV 128/130)

Answer

TE metric (TLV 138)

Question 10

Which BGP attribute influences inbound traffic to an AS by affecting the path selection of eBGP peers?

Accepted Answer

MED. MED (Multi-Exit Discriminator) is used to influence inbound traffic by suggesting to a neighbor AS which path to use.

Answer

LOCAL_PREF

Answer

Weight

Answer

AS_PATH