Nokia IP Networks and Services Fundamentals 4A0-100 Exam Practice Test

Answer : C

The Internet Assigned Numbers Authority (IANA) is responsible for managing the global IP address pool, along with:

Allocating blocks of IP addresses to Regional Internet Registries (RIRs) such as ARIN (North America), RIPE NCC (Europe), APNIC (Asia-Pacific), etc.

Managing autonomous system numbers (ASNs).

Overseeing DNS root zones and protocol parameters.

IANA does not assign IPs directly to enterprises or individuals --- those tasks are delegated to RIRs and ISPs.

Option A & B: Enterprises and residential allocations are handled by ISPs or RIRs.

Option D: North American IPs are managed by ARIN, not IANA.

Option C is correct -- IANA manages the global IP address allocation hierarchy.

IANA official site: https://www.iana.org

Nokia IP Fundamentals -- IP Address Management and Allocation Hierarchy

Answer : C

A VPRN (Virtual Private Routed Network) provides a Layer 3 VPN service over a service provider's network.

Each customer site connects to a PE router.

Sites are connected via a routed network using separate routing instances.

Customer routers see routed connectivity, as if connected to their own private WAN.

Option C is correct -- VPRN provides routed connectivity between sites.

Nokia Service Routing Guide -- Chapter: VPRN

Nokia SRA Guide -- Service Types and Operation

Answer : C

The Shortest Path Tree (SPT) is calculated by Link-State routing protocols like OSPF and IS-IS using:

A complete map of the network topology.

Each router uses algorithms like Dijkstra's to compute the shortest paths to all destinations.

Option C is correct -- full network topology is used.

Option A refers to Distance Vector methods.

Option B and D are results of topology analysis but not the input used.

Nokia Routing Protocols Guide -- Section: ''SPT and Link-State Behavior''

RFC 2328 -- OSPF Specification

Answer : B

Spanning Tree Protocol (STP) is used specifically in Ethernet Layer 2 networks to prevent loops caused by redundant paths.

STP detects loops and blocks one or more redundant paths to ensure there is a loop-free topology in a bridged network.

STP dynamically recalculates the topology if a link fails, reactivating previously blocked paths.

Explanation of other options:

A . MPLS with LSPs: MPLS uses its own mechanisms for path management, such as RSVP or Segment Routing. STP is not applicable here.

C . OSPF with ECMP (Equal-Cost Multi-Path): OSPF is a Layer 3 protocol that inherently supports multiple paths without loops; STP is not involved.

D . eBGP (Exterior Border Gateway Protocol): Operates at Layer 3 for inter-AS communication; STP is not used in BGP routing.

Therefore, Option B is correct, as STP is explicitly designed for Layer 2 Ethernet networks with redundant paths.

Nokia IP Networking Fundamentals Study Guide -- Chapter: 'Layer 2 Technologies'

IEEE 802.1D Standard -- Spanning Tree Protocol Overview

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

Answer : A

The Ingress Label Edge Router (LER) is the first router that:

Receives an unlabeled IP packet.

Applies an MPLS label based on its forwarding decision.

Forwards it into the MPLS core.

Option A is correct -- Ingress LER does MPLS label push.

Option B (Egress LER) -- removes labels at the end of the path.

Option C (LSR) -- switches labels, but doesn't push them onto unlabeled packets.

Option D -- is not a specific MPLS role.

Nokia IP/MPLS Fundamentals Guide -- Label Operations

RFC 3031 -- MPLS Architecture

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