Nokia 4A0-100 Exam Dumps

A hub is a physical layer (Layer 1) networking device used to connect multiple Ethernet devices in a network. Unlike switches or routers, hubs do not inspect or process frame headers. Instead, they perform a simple task:

Receive a signal (electrical or optical) on one port

Replicate that signal identically to all other ports

This means the hub does not examine Layer 2 (MAC addresses) or Layer 3 (IP addresses) and does not perform intelligent forwarding. It merely broadcasts all incoming traffic to every other connected device, often resulting in high collision domains and poor efficiency.

Option A describes a repeater, not a hub.

Option C describes a switch (Layer 2 device).

Option D describes a router (Layer 3 device).

Option B is correct: A hub does not inspect headers and replicates traffic blindly.

Nokia IP Networking Fundamentals Study Guide -- Chapter: 'Network Devices and OSI Model'

CompTIA Network+ and Cisco CCNA foundational guides (for universally accepted hardware behavior)

The Model-Driven Command Line Interface (MD-CLI) in Nokia SR OS provides a structured and programmatic way to manage configurations. It is based on a transactional model, meaning changes are made in a candidate configuration before being committed to the running configuration.

Let's review each statement:

Nokia SR OS MD-CLI User Guide

Nokia SRA Study Guide -- Chapter: 'Model-Driven Configuration and Transactions'

A static route is a manually configured route added by a network administrator. It does not rely on dynamic routing protocols or metrics.

It does not exchange routes with other routers (A -- false).

It can be used both within or across ASes (B -- false).

It does not use metrics like hop count (C -- false).

Option D is correct -- the operator explicitly defines the next-hop IP or egress interface manually.

Static routes are often used for:

Default routing

Backup routing

Simple or small networks

Nokia IP Fundamentals -- Chapter: ''Static vs Dynamic Routing''

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

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