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

Answer : C

Nokia IP Fundamentals Guide -- Chapter: ''Subnetting and Address Calculations''

Subnet Math -- RFC 950 principles

Answer : D

A MAC address (Media Access Control address) is a 48-bit identifier typically expressed in six groups of two hexadecimal digits (e.g., 00-20-60-CE-2B-28). It consists of two key parts:

OUI (Organizationally Unique Identifier) -- The first 24 bits (or first 3 octets, e.g., 00-20-60) are assigned by the IEEE to hardware manufacturers. This identifies the vendor or manufacturer.

Device Identifier (NIC Specific) -- The remaining 24 bits (e.g., CE-2B-28) are assigned uniquely by the vendor to each device/interface.

So in the address 00-20-60-CE-2B-28:

00-20-60 is the OUI

CE-2B-28 is the device-specific portion

Thus, the correct answer is D. 00-20-60.

IEEE MAC Address Standard (IEEE 802)

Nokia IP Networking Fundamentals Study Guide -- Chapter: 'Ethernet Addressing'

Answer : B

The system interface in Nokia SR OS is a loopback-style logical interface that represents the router itself. It is used for:

Router ID assignment (if not manually set)

Source IP for control-plane protocols (OSPF, BGP)

Reachability testing

Important properties:

It is type loopback

It exists by default

If router ID is unset, it uses the system IP address

But the IP address on the system interface does not need to be /32

It can have other prefix lengths, especially in service provider scenarios.

Thus, Option B is FALSE.

Nokia SRA Study Guide -- Chapter: 'System Interface and Loopbacks'

Nokia SR OS Fundamentals Guide -- System IP Configuration Section

Answer : D

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''

Answer : C

A layered protocol stack is designed to simplify network communication by separating functionalities into distinct layers. Each layer has a defined role and communicates with the layers directly above and below it. The main benefits of this model include:

Simplified design and implementation: Developers can focus on one layer without needing to understand the entire system.

Flexibility: New protocols can be developed and inserted at specific layers without redesigning the whole stack.

Interoperability: Standard interfaces allow different systems and vendors to work together.

Isolation of functions: Errors and updates can be managed within one layer without impacting others.

However, reducing protocol overhead is not a primary goal of this model. In fact, the encapsulation and interaction between layers can sometimes introduce extra overhead. This overhead is a trade-off accepted to gain the other benefits listed above.

Answer : B

VLAN Stacking, also known as Q-in-Q tunneling, is a technology that allows multiple customers to use overlapping VLAN IDs while being transported over a shared service provider network.

Key Concepts:

Customer VLAN (C-VLAN): The VLAN used by the customer in their own network.

Service VLAN (S-VLAN): The VLAN used by the service provider to encapsulate the customer VLAN.

When VLAN stacking is applied:

A customer's Ethernet frame already tagged with a C-VLAN is encapsulated with an additional outer S-VLAN tag.

This way, multiple customers can use the same C-VLAN ID, but remain isolated by the unique S-VLAN assigned to them by the service provider.

Why Other Options Are Incorrect:

A . VLAN Trunking: Used to carry multiple VLANs over a single physical link but doesn't allow reuse of VLAN IDs across customers.

C . VLAN Tagging: Refers to the general process of adding a VLAN tag; it doesn't provide the isolation needed across shared infrastructure.

D . VLAN Routing: Refers to Layer 3 routing between VLANs, not to ID reuse or transport over a shared provider backbone.

Nokia Service Architecture and VPNs Study Guide -- Section: ''Q-in-Q VLAN Stacking''

IEEE 802.1ad Standard -- Provider Bridges (Q-in-Q)

Answer : D

In the diagram:

R2 and R4 are both within AS 65540, which indicates that they are in the same Autonomous System.

eBGP (External Border Gateway Protocol) is designed for routing between different ASes (inter-AS routing).

Since R2 and R4 are in the same AS, you would use:

OSPF or IS-IS (both interior gateway protocols -- IGPs)

Static routing is also valid between any two routers if manually configured

eBGP is invalid between routers in the same AS.

The correct protocol in that case would be iBGP (internal BGP) if BGP were to be used within the AS.

Therefore, the correct answer is: D. eBGP

Nokia IP Routing Fundamentals -- BGP vs IGP

Nokia SRA Guide -- AS Concepts and Protocol Suitability

RFC 4271 -- BGP Specification