Pass the Nokia Network Routing Specialist II (NRS II) 4A0-114 Questions and answers with ValidTests

Understanding the Network Topology:

Routers are part of different ASes: Router A and Router B are in AS 65540, Router D is in AS 65550, and Router E is in AS 65560.

To allow Router B to exchange traffic with Router D, proper iBGP (internal BGP) configuration is required within AS 65540.

Configuration Requirements:

The configuration on Router A should include:

Enabling IPv6 family for BGP.

Setting the next-hop-self to ensure that the BGP next-hop is reachable.

Specifying the type as internal to denote an iBGP session.

Configuring the neighbor as Router B's IPv6 address.

Analyzing Options:

Option A: Missing the type internal configuration.

Option B: Missing the family ipv6 configuration.

Option C: Missing both next-hop-self and type internal configurations.

Option D: Correctly includes all necessary commands:

family ipv6

next-hop-self

type internal

neighbor 2001:DB8:2::2

Conclusion:

Option D provides a complete configuration for Router A to enable traffic exchange between Router B and Router D using iBGP with IPv6.

References

Nokia Border Gateway Protocol (BGP) Fundamentals documentation

Best practices for iBGP and eBGP configurations

IPv6 addressing and BGP configurations in multi-AS environments

BGP Message Types: BGP uses several types of messages for various functions: Open, Update, Notification, and Keep-Alive.

Keep-Alive Message: This type of message is sent periodically to verify connectivity between BGP peers. After the BGP session is established with Open messages, Keep-Alive messages ensure the session remains active and monitor the health of the connection.

Connectivity Verification: During the establishment of a BGP session, the Open message is initially used. Post-establishment, Keep-Alive messages are sent at regular intervals to maintain the connection and to verify that both peers are still reachable and operational.

References:

Nokia BGP Fundamentals Documentation, Chapter on BGP Message Types

RFC 4271 (A Border Gateway Protocol 4), Sections 4.2 and 4.4

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.

IPv6 BGP Session Requirements: To establish an IPv6 BGP session, the configuration must include the IPv6 addresses of the neighbors and the appropriate family settings.

Option Analysis:

Option A: Incorrect. The configuration does not match typical BGP IPv6 configuration standards for Nokia routers.

Option B: Incorrect. The configuration is incomplete for establishing an IPv6 BGP session.

Option C: Correct. The configuration includes the appropriate neighbor IPv6 address and family settings required to establish an IPv6 BGP session.

Option D: Incorrect. The configuration has errors or missing components needed for a proper IPv6 BGP session.

Conclusion: Option C provides the correct configuration necessary to establish an IPv6 BGP session between router A and router B.

References:

Nokia Border Gateway Protocol Fundamentals

Nokia 7750 SR OS BGP Configuration Guide

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.

When a BGP router receives multiple routes for the same destination, it selects the best route based on several attributes in the following order of preference:

Highest local preference: Routes with the highest local preference are preferred.

Shortest AS_PATH: Routes with the shortest AS path are preferred.

Lowest MED: Routes with the lowest MED are preferred.

eBGP over iBGP: Routes learned via eBGP are preferred over iBGP routes.

Lowest IGP metric to BGP next hop.

Given the routes:

Local preference 100, MED 150, AS Path 65300 65200 (eBGP)

Local preference 100, MED 100, AS Path 63200 (iBGP)

Local preference 200, MED 150, AS Path 65400 63200 (iBGP)

Local preference 200, MED 100, AS Path 63700 (eBGP)

Route 4 has the highest local preference (200), the lowest MED (100), and is learned via eBGP. Therefore, it is the best route.

ReferencesNokia Border Gateway Protocol Fundamentals, Chapter on BGP Route Selection Process.

A distributed EVPN VPRN service acts as a router for IP packets between customer sites.

It does require two types of interfaces: one towards customer sites (CEs) and another towards the EVPN VPLS for backhaul connectivity.

The configured route target (RT) helps PE routers identify relevant BGP updates.

MP-BGP with the EVPN address family is used to populate the routing table.

Therefore, the statement "It requires two types of interfaces, one towards customer sites and one towards the backhaul VPLS." is FALSE because the backhaul VPLS reference should instead pertain to VPRN backhaul routing.

References:

Nokia Border Gateway Protocol Fundamentals documentation, Section 9.2 on EVPN VPRN interface requirements and configuration.

Route reflectors (RR) are used in BGP to reduce the number of iBGP sessions required within an Autonomous System (AS). Here are key points about route reflectors:

B. True: A route reflector can have both iBGP and eBGP clients, allowing it to propagate routes between internal and external peers.

C. True: A route reflector disables the iBGP split-horizon rule for its clients, allowing it to propagate routes received from one iBGP client to other iBGP clients.

D. True: Route reflectors reduce the number of iBGP sessions required in an AS by allowing clients to form iBGP sessions only with the route reflector instead of with every other iBGP peer.

The false statement is:

A. False: A full iBGP mesh is not required among route reflectors themselves. Instead, route reflectors can form a partial mesh or hierarchical structure to propagate routes efficiently.

ReferencesNokia Border Gateway Protocol Fundamentals, Chapter on Route Reflectors.

Understanding Path-ID: The BGP Path Identifier (Path-ID) is a concept used in BGP to support the advertisement of multiple paths for the same prefix without requiring multiple BGP sessions.

Path-ID Details:

Option A: Incorrect because the Path-ID is not pre-pended to the NLRI (Network Layer Reachability Information) field of a BGP update. It is part of the BGP Multipath feature and used to uniquely identify different paths.

Option B: Correct. Path-ID is an optional transitive attribute that allows for the advertisement of multiple paths.

Option C: Correct. Path-ID uniquely identifies each path advertised to a neighbor.

Option D: Correct. A BGP speaker that re-advertises a route must generate its own Path-ID.

Conclusion: Option A is false because it incorrectly describes the placement of the Path-ID.

References:

Nokia Border Gateway Protocol Fundamentals

RFC 7911 - Advertisement of Multiple Paths in BGP

An EVPN IP-Prefix (type 5) route update is used for Layer 3 VPNs and includes information necessary for routing within the VPLS.

It carries the IP prefix of the subnet, the VPLS's route-distinguisher (RD), and route-target (RT) values, as well as the service tunnel ID (e.g., MPLS label or VNI value).

The MAC address of an attached host is not included in a type-5 route update.

Therefore, the statement "The MAC address of an attached host." is NOT carried inside an EVPN IP-Prefix (type 5) route update.

References:

Nokia Border Gateway Protocol Fundamentals documentation, Section 10.4 on EVPN IP-Prefix route attributes.