Nokia 4A0-100 Exam Questions Instant Access

Question 1

Which of the following statements about IP route summarization is FALSE?

AIt divides a customer IP address pool into smaller portions, each of which is assigned to a different subnet.

BIt reduces the size of the routers' forwarding tables.

CIt improves scalability of the network.

DIt increases routing advertisement stability.

Answer : A

Route summarization (a.k.a. supernetting) is the process of combining multiple contiguous subnets into a single summarized route, which:

Reduces routing table entries

Enhances scalability and efficiency

Minimizes instability by localizing route changes

Option A is false because it describes subnetting, not summarization. Summarization works in the opposite direction -- combining smaller routes into a larger one.

Nokia IP Routing Guide -- Chapter: ''Route Summarization Techniques''

Cisco CCNA -- IP Routing Concepts

Question 2

Which of the following statements about the VPWS service on a Nokia 7750 SR is FALSE?

AVPWS is a point-to-point service.

BVPWS emulates a layer-2 connection between two customer sites.

CVPWS does not perform MAC learning.

DVPWS encapsulates layer-2 frames into IP datagrams.

Answer : D

VPWS (Virtual Private Wire Service) on Nokia 7750 SR:

Emulates a Layer 2 point-to-point connection.

Does not require MAC learning, unlike VPLS.

Uses MPLS encapsulation, not IP datagrams for transport.

Option D is FALSE -- VPWS uses MPLS labels, not IP encapsulation.

Nokia 7750 SR Service Router Guide -- VPWS Overview

Nokia SRA Study Guide -- Chapter: Layer 2 Services

Question 3

Which of the following statements best describes BGP route selection?

AIt uses SPF algorithm to calculate the shortest paths.

BIt uses link metrics to calculate the shortest paths.

CIt uses multiple criteria to choose the best routes.

DIt uses the preference value to choose the best routes.

Answer : C

BGP (Border Gateway Protocol) uses a multi-step decision process to select the best route among multiple paths. It does not use SPF or simple metrics like hop count.

Key BGP selection criteria include:

Local preference

AS path length

Origin type

MED (Multi-Exit Discriminator)

eBGP over iBGP

IGP metric to next hop

Option C is correct -- BGP evaluates multiple attributes for route selection.

Nokia IP Routing Fundamentals -- BGP Route Selection

RFC 4271 -- BGP Decision Process

Question 4

Which compact flash on a control processing module (CPM) of a Nokia 7750 SR stores the runtime software image and the configuration file?

ACF1

BCF2

CCF3

DBoth CF1 and CF2

Answer : C

Question 5

Which of the following statements about VPLS is FALSE?

AA VPLS emulates a virtual switch or bridge.

BA VPLS learns source MAC addresses from SAPs and SDPs.

CA VPLS discards frames with unknown MAC destinations.

DA MAC address forwarding database (FDB) is maintained for each VPLS.

Answer : C

VPLS (Virtual Private LAN Service) is a Layer 2 VPN service that emulates a bridged Ethernet LAN across an MPLS/IP network.

Learns MAC addresses dynamically from:

SAPs (Service Access Points)

SDPs (Service Distribution Points)

Maintains a Forwarding Database (FDB) per VPLS instance.

For unknown MAC destinations, a VPLS floods the frame to all other sites -- just like a regular Ethernet switch.

Option C is FALSE -- VPLS does NOT discard unknown MACs; it floods them.

Nokia VPLS Services Guide -- Learning and Forwarding

Nokia SRA Study Guide -- VPLS Operation

Question 6

Which of the following statements about ICMP functions is FALSE?

AUsed to test end-to-end connectivity.

BCan be used to identify the hops that traffic must pass through to get to the destination.

CUtilizes different return codes for error reporting.

DProvides an automatic re-route if destination is unreachable.

Answer : D

ICMP (Internet Control Message Protocol) is used for network diagnostics and error messaging. Key uses include:

Ping (Echo Request/Reply) -- tests end-to-end connectivity

Traceroute -- uses ICMP time exceeded messages to identify hops

Error reporting -- returns various error types with different codes

However, ICMP does not re-route traffic. If a destination is unreachable, ICMP reports the error back to the sender; it doesn't instruct routers to re-route.

Option D is FALSE -- ICMP does not perform routing.

Nokia IP Fundamentals Guide -- Section: ''ICMP and Network Diagnostics''

RFC 792 -- ICMP Standard

Question 7

Which of the following is a characteristic of a subnet created with a /31 prefix?

AThere is no broadcast address on the network.

BThe address is only used as a loopback address.

CThis specifies a single host address.

DThe address is only used for router IDs.

Answer : A

A /31 subnet in IPv4 provides exactly two IP addresses (e.g., 192.168.1.0/31 usable: 192.168.1.0 and 192.168.1.1). Traditionally, these would represent a network address and a broadcast address, but RFC 3021 redefines /31 subnets for point-to-point links, such as router-to-router connections.

In a /31 subnet:

Broadcast address is not used.

Both IPs are treated as usable host addresses.

It's ideal for point-to-point links, saving address space.

This is widely supported and standardized in Nokia IP and routing platforms.

Nokia IP Fundamentals Guide -- Subnetting Techniques

RFC 3021 -- 'Using 31-Bit Prefixes on IPv4 Point-to-Point Links'

Nokia IP Networks and Services Fundamentals 4A0-100 Exam Questions