Nokia Nokia Border Gateway Protocol Fundamentals for Services 4A0-114 Exam Dumps: Updated Questions & Answers (October 2025)

BGP Shortcuts Concept: BGP shortcuts leverage MPLS tunnels to carry transit traffic efficiently across the network, reducing the need for full-mesh iBGP peering.

Statement Analysis:

Option A: Correct. MPLS tunnels are indeed used to carry transit traffic across the network.

Option B: Correct. A full mesh of iBGP peering sessions is not required when using BGP shortcuts.

Option C: Incorrect. Only edge routers need to be configured with BGP. Transit routers only need to support MPLS (LDP or RSVP-TE) but do not need to run BGP.

Option D: Correct. Transit routers need to support LDP (Label Distribution Protocol) or RSVP-TE (Resource Reservation Protocol-Traffic Engineering) LSPs (Label Switched Paths).

Conclusion: Option C is false because transit routers do not need to be configured with BGP.

References:

Nokia Border Gateway Protocol Fundamentals

Nokia 7750 SR OS BGP Configuration Guide

Route reflector clusters help in organizing route reflectors within an AS to manage scalability and redundancy. Here are key points about route reflector clusters:

A. True: Multiple clusters may be configured within an AS to improve scalability and load distribution.

B. False: Within an AS, route reflectors belonging to different clusters do need to be fully-meshed among themselves to ensure proper route propagation and to avoid routing loops.

C. True: A router can be the client of multiple route reflectors within its AS, providing redundancy and load balancing.

D. True: When a route reflector reflects a route, it adds its cluster ID to the Cluster_list attribute to prevent routing loops and ensure proper route propagation.

ReferencesNokia Border Gateway Protocol Fundamentals

When a BGP session is stuck in the "Connect" state, it indicates that the local router is attempting to establish a TCP connection, but it hasn't succeeded yet. This often occurs when the remote BGP peer isn't configured correctly or there is an issue with the remote peer's reachability. Here are the potential reasons why this happens:

The remote BGP peer might not be configured to accept the BGP session.

There might be network issues preventing the local router from reaching the remote peer.

Given the options, if the local router is properly configured but the remote peer isn't, the session would be stuck in the "Connect" state as it waits for a successful TCP connection.

ReferencesNokia Border Gateway Protocol Fundamentals, Troubleshooting BGP Sessions, Chapter on BGP State Machine and Connection Issues.

To prevent route advertisement loops in a network using route reflectors, specific attributes are employed.

The key attributes used for loop prevention in BGP are:

MED (Multi-Exit Discriminator): Used to influence the incoming traffic from neighboring ASes. It is not used for loop prevention.

ORIGIN: Indicates the origin of the route but does not directly prevent loops.

CLUSTER_LIST: Used by route reflectors to prevent loops. When a route reflector propagates a route, it adds its cluster ID to the CLUSTER_LIST. If a route with its own cluster ID is received, it is rejected to prevent loops.

AS_PATH: Records the ASes a route has traversed, preventing loops by rejecting routes containing the local AS number.

Therefore, the CLUSTER_LIST attribute is specifically used by route reflectors to prevent routing loops by keeping track of the clusters a route has passed through.

References:

Nokia Border Gateway Protocol Fundamentals documentation, Section 6.5 on Attributes for Loop Prevention in Route Reflectors.

When a TCP connection fails to be established with a BGP peer, the BGP state machine goes through several states. The initial state is "Idle". In this state, BGP initializes all resources and awaits a start event. After initiating a TCP connection to the peer, it transitions to the "Connect" state. If the TCP connection attempt is unsuccessful, the state will transition to "Active", where BGP will continue to try to establish the TCP connection.

Idle: BGP is waiting for a start event to initialize a connection.

Connect: BGP is trying to establish a TCP connection.

Active: BGP attempts to establish a connection if the previous TCP connection attempt fails.

Since the question specifies the failure of TCP connection establishment, the valid states are "Idle" and "Active".

ReferencesNokia Border Gateway Protocol Fundamentals, Chapter on BGP States and the BGP Finite State Machine.

Route Distinguishers (RDs) are used in BGP/MPLS VPNs to ensure unique VPN-IPv4 prefixes. Here are the characteristics of RDs:

A. True: An RD is prepended to an IPv4 prefix to form a VPN-IPv4 prefix.

B. True: An RD is used to indicate the VPRN service to which a route update is relevant.

C. True: A unique RD value is assigned to each VPRN service.

The false statement is:

D. False: An RD is a 64-bit value. In reality, an RD is a 96-bit value (composed of a 2-byte Type field and a 6-byte Value field).

ReferencesNokia Border Gateway Protocol Fundamentals, Chapter on Route Distinguishers and VPN-IPv4.

Ethernet VPN (EVPN) services provide advanced features for layer-2 and layer-3 connectivity among customer sites. Here are key points about EVPN:

A. True: The goal of an EVPN service is to provide layer-2 or layer-3 connectivity among two or more customer sites.

B. False: A local layer-2 EVPN service is not referred to as a backhaul VPLS. Backhaul VPLS is a different service concept used to transport layer-2 traffic over a layer-3 network.

C. True: The same BGP address family (EVPN) can be used to populate the forwarding database of an EVPN VPLS and the route table of an EVPN VPRN.

D. True: EVPN services support signaling for the use of MPLS and VXLAN tunnels.

ReferencesNokia Border Gateway Protocol Fundamentals, Chapter on EVPN Services.

A type-2 EVPN route update is used to carry host-specific information.

It includes the MAC address of the host and optionally the associated IP address.

This type of update allows for efficient MAC and IP address learning and advertisement within the EVPN.

Therefore, the type-2 EVPN route update carries a host MAC address and optionally the associated IP address.

References:

Nokia Border Gateway Protocol Fundamentals documentation, Section 11.2 on type-2 EVPN route updates.

EVPN (Ethernet VPN) VPLS (Virtual Private LAN Service) uses MP-BGP to exchange reachability information.

When PE1 and PE2 exchange MP-BGP route updates for VPLS 300, the addressing information included pertains to EVPN MAC addresses.

This is because EVPN uses MAC address learning over MP-BGP to provide the Layer 2 VPN service.

References:

Nokia Border Gateway Protocol Fundamentals documentation, Section 8.3 on EVPN route updates and MAC address learning.

VXLAN (Virtual Extensible LAN) is a network virtualization technology that encapsulates layer-2 Ethernet frames within layer-3 UDP packets. This encapsulation allows for the creation of virtual networks over a physical IP network. The true statement about VXLAN encapsulation is as follows:

Transport Tunnel Identification: An additional IP header is used to identify the transport tunnel. This header includes the source and destination IP addresses that identify the endpoints of the VXLAN tunnel.

Service Tunnel Identification: The VXLAN Network ID (VNI) is used to identify the service tunnel. The VNI is a 24-bit identifier that distinguishes different VXLAN segments.

This encapsulation enables the extension of layer-2 networks across layer-3 boundaries, allowing for scalable and flexible network designs.

ReferencesNokia Border Gateway Protocol Fundamentals, Chapter on Network Virtualization and VXLAN.