4A0-100 Exam Dumps : Nokia IP Networksand Services Fundamentals

In MPLS architecture, theIngress LER (Label Edge Router)is responsible for:

Pushing labelsonto unlabeled packets and injecting them into the MPLS domain.

Acting as thestarting point of the Label Switched Path (LSP).

From the diagram:

R1is thestarting point (Ingress LER)for both LSP A and LSP B.

R4is theEgress LER, which wouldpopthe labels at the end of the LSP.

So,R1 is responsible for label push (imposing)at the start of both LSPs.

Option A is correct– R1 pushes labels for both LSP A and LSP B.

Option Bis incorrect – R4 is an egress router, not ingress.

Option C/Dare incorrect – the LSPs both start at R1.

Ahubis aphysical layer (Layer 1)networking device used to connect multiple Ethernet devices in a network. Unlike switches or routers, hubs donot 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 hubdoes not examine Layer 2 (MAC addresses) or Layer 3 (IP addresses)and doesnot perform intelligent forwarding. It merelybroadcasts all incoming traffic to every other connected device, often resulting inhigh collision domainsand poor efficiency.

Option Adescribes arepeater, not a hub.

Option Cdescribes aswitch(Layer 2 device).

Option Ddescribes arouter(Layer 3 device).

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

Abroadcast domainis a logical division of a network in which all nodes can reach each other with broadcast frames (Layer 2). Devices within the same broadcast domain receive broadcast packets sent by others.

In the diagram:

Multiple users connect tohubs.

Hubs are Layer 1 devices anddo not break broadcast domains. They simply replicate incoming electrical signals to all ports.

Hubs are then connected toswitches.

Switches, unless VLANs are configured,forward broadcasts to all ports except the incoming one, effectively keeping all devices in the same broadcast domain.

The two switches are connected together without VLAN segmentation.

Therefore:

The entire LAN depicted isa single Layer 2 broadcast domain.

There areno routers or VLANsto break or separate the domain.

Correct answer: A. 1