Nokia 4A0-100 Exam Dumps

A P router (Provider router) is located in the core of the service provider's network. Its functions include:

Forwarding MPLS-labeled packets between PE routers.

Not interacting directly with customer routes or routing instances.

Having no knowledge of VPN routing or customer-specific services.

Option C is correct -- P routers sit in the MPLS core, isolated from customer edge.

Nokia MPLS and Services Guide -- Core vs Edge Router Roles

Nokia SRA Study Guide -- 'PE and P Devices in MPLS'

Comprehensive and Detailed Explanation From Exact Extract:

In the Nokia SR OS CLI, specifically in both classic CLI and MD-CLI, the '?' key is used to display a list of all possible command options at a given point in the CLI, along with a brief description of each option.

This functionality helps the user in command discovery and reduces the chances of syntactical errors by showing only valid options.

The 'Tab' key, while helpful, is primarily used for auto-completion and not for displaying detailed descriptions.

'Space bar' is used for command continuation, and 'Return' executes the command or moves to the next line.

Correct usage example in classic CLI:

*A:SR1>config>router>interface# ?

- Shows all the valid commands and parameters under interface

Nokia SRA Study Guide -- Chapter: 'CLI Fundamentals'

Nokia SR OS Fundamentals Guide -- Section: 'Using the CLI Help System'

A Virtual Local Area Network (VLAN) is a logical separation of devices at Layer 2, even if those devices are connected to the same physical switch. Each VLAN forms its own broadcast domain, and traffic cannot cross from one VLAN to another without Layer 3 routing.

Option A is incorrect -- devices on the same switch but in different VLANs still cannot communicate directly.

Option B is incorrect -- VLANs explicitly create separate broadcast domains.

Option D is technically incorrect -- communication is possible with the right setup.

Option C is correct -- to enable communication between different VLANs, a router or a Layer 3 switch with inter-VLAN routing capability is required.

This process is called inter-VLAN routing, and it's a fundamental task in enterprise networks using VLANs.

Nokia IP Networking Fundamentals Study Guide -- Chapter: 'LAN Segmentation and VLANs'

Cisco CCNA and CompTIA Network+ -- Inter-VLAN Routing Concepts

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