Nokia Service Routing Architect Certified Official Practice Test 4A0-115 - May-2024
Ace Nokia 4A0-115 Certification with Actual Questions May 16, 2024 Updated
NEW QUESTION # 17
In the exhibit, the default algorithm is used to elect the designated forwarder (DF) on ESI 1. Which PE is elected as DF for VPLS 10?
- A. PEI
- B. PE3
- C. PE2
- D. PE4
Answer: C
Explanation:
Explanation
PE2 is elected as DF for VPLS 10. The default algorithm uses the lowest IP address of thePEs attached to the same Ethernet segment as the tie-breaker criterion. PE2 has the lowest IP address among PE1, PE2, and PE3.
NEW QUESTION # 18
Examine the exhibit.
Which of the following statements about the operation of EVPN VPWS 4 is FALSE?
- A. PE2 receives a single A-D per EVI route. The route is originated from PE3.
- B. PE3 sets the P flag in its advertised A-D per EVI route to I.
- C. PEI brings the SAP in VPWS 4 operationally down.
- D. PE2 receives two A-D per ES routes: one from PEI and another from PE3.
Answer: B
Explanation:
Explanation
PE3 does not set the P flag in its advertised A-D per EVI route to 1. PE3 sets the P flag to 0, indicating that it is not the DF for EVI 20. PE1 sets the P flag to 1, indicating that it is the DF for EVI 201.
Verified References: Ethernet Virtual Private Networks (EVPNs)
NEW QUESTION # 19
In the exhibit, an EVI range is configured and the preference-based algorithm is used to elect the designated forwarder (DF) on ESI 1. Which PE is elected as DF for VPLS 10?
- A. PE3
- B. PE2
- C. PEI
- D. PE4
Answer: A
Explanation:
Explanation
PE3 is elected as DF for VPLS 10. The preference-based algorithm uses the highest preference value of the PEs attached to the same Ethernet segment as the tie-breaker criterion. PE3 has the highest preference value among PE1, PE2, and PE3.
NEW QUESTION # 20
Which of the following statements about EVPN auto-discovery per EVPN instance (A-D per EVI) routes is FALSE?
- A. A PE advertises an A-D per EVI route for each operational service defined on an Ethernet segment.
- B. The updates are used to discover all the PES associated with an Ethernet segment.
- C. A PE uses the received updates to create aliasing lists to PES that are part of an all-active Ethernet segment.
- D. The updates include an Ethernet tag ID that is set to zero.
Answer: A
Explanation:
Explanation
A PE does not advertise an A-D per EVI route for each operational service defined on an Ethernet segment. A PE advertises a single A-D per EVI route for all services defined on an Ethernet segment.
NEW QUESTION # 21
The interface-ful numbered model is used for a Layer-3 EVPN service. Which of the following statements is FALSE?
- A. EVPN MAC/IP routes are used to advertise the MAC and IP addresses of local hosts.
- B. EVPN MAC/IP routes are used to advertise the MAC and IP addresses of SBD IRB interfaces.
- C. EVPN routes are advertised with a service label associated with the SBD VPLS.
- D. IP-Prefix routes exchanged between PES include a non-zero gateway IP address as an overlay index.
Answer: B
Explanation:
Explanation
EVPN MAC/IP routes are not used to advertise the MAC and IP addresses of SBD IRB interfaces. EVPN MAC/IP routes are used to advertise the MAC and IP addresses of local hosts attached to the SBD VPLS2.
Verified References: Nokia Ethernet Virtual Private Network Services Course | Nokia
NEW QUESTION # 22
Examine the exhibit.
Which of the following actions is performed by PEI after it receives a BUM packet from CEI?
- A. PEI sends the packet to PE2 but not to PE3 because PE3 is connected to the originating ES.
- B. PEI sends the packet to PE2 and to PE3. An ESI label is included only in the packet sent to PE2.
- C. PEI sends the packet to PE2 and to PE3. An ESI label is included only in the packet sent to PE3.
- D. PEI does not flood the packet because PEI is acting as non-designated forwarder (non-DF) for VPLS 10.
Answer: B
Explanation:
Explanation
PE1 sends the packet to PE2 and to PE3. An ESI label is included only in the packet sent to PE2. The ESI label is used to implement the split-horizon mechanism and prevent traffic duplication. The packet sent to PE3 does not need an ESI label because PE3 is connected to the same Ethernet segment as PE1.
NEW QUESTION # 23
In the exhibit, VPWS 4 enables communications between CEI and CE2. Which of the following statements regarding the operation of VPWS 4 is FALSE?
- A. PEI advertises an auto-discovery per EVPN instance (A-D per EVI) route to PE3 as soon as the SAP becomes operationally
- B. PE3 and PE4 exchange their service labels over an established targeted LDP session.
- C. PEI and PE3 exchange their service labels using A-D per EVI routes.
- D. PE3 advertises an IMET route to PEI as soon as VPWS 4 is administratively enabled.
Answer: C
Explanation:
Explanation
PE1 and PE3 do not exchange their service labels using A-D per EVI routes. PE1 and PE3 exchange their service labels using MAC routes, which are advertised when their local ACs become operationally UP1.
Verified References: Ethernet Virtual Private Networks (EVPNs)
NEW QUESTION # 24
Examine the exhibit.
Which of the following configuration is NOT required to enable Layer-2 communication between CEI and CE2?
- A. Configure an MP-BGP session that allows the exchange of EVPN routes between PEI and PE3.
- B. Configure an MP-BGP session that allows the exchange of IPv4 labeled routes between PE3 and PE4.
- C. Configure a local attachment circuit (AC) and a remote AC for VPWS 4 on all PE routers.
- D. Configure a service distribution point (SDP) on PE3 to reach PE4, and another SDP on PE4 to reach PE3.
Answer: D
Explanation:
Explanation
The advertisement of IP-Prefix routes is not required to enable Layer-2 communication between CE1 and CE2. IP-Prefix routes are used to enable Layer-3 communication between different subnets in an EVPN-IRB service. For Layer-2 communication, only MAC/IP routes are required2.
Verified References: Nokia Ethernet Virtual Private Network Services Course | Nokia
NEW QUESTION # 25
Examine the exhibit.
Which of the following statements about the operation of VPLS 20 is TRUE?
- A. The flooding list maintained by PEI for VPLS 20 contains three entries: PE2, PE3, and PE4.
- B. PE3 signals a service label to PE4 when its VPLS 20 is enabled and is bound to an operational SDP.
- C. PEI advertises a MAC route for MAC-OI when its VPLS 2(Ys SAP becomes operationally UP.
- D. PE3 advertises an IMET route to PEI when its VPLS 20's mesh-SDP becomes operationally UP.
Answer: C
Explanation:
Explanation
PE1 does not advertise a MAC route for MAC-01 when its VPLS 20's SAP becomes operationally UP. PE1 advertises an EVPN MAC/IP route for MAC-01, which includes the IP address of Host 1 and the ESI of the Ethernet segment1.
Verified References: Ethernet Virtual Private Networks (EVPNs)
NEW QUESTION # 26
Which of the following statements about multi-homing for a Layer-2 service is TRUE?
- A. In the all-active mode, all PES attached to a CE can forward traffic to and from the CE.
- B. The Nokia 7750 SR supports a CE being multi-homed to a maximum of two PEs.
- C. In the single-active mode, the CE forwards traffic to all attached PES and receives traffic from a single PE.
- D. In the single-active mode, the CE requires a LAG to be configured between the CE and all attached PEs.
Answer: A
Explanation:
Explanation
In the all-active mode, all PEs attached to a CE can forward traffic to and from the CE. This provides load balancing and redundancy for the CE. The CE does not require a LAG to be configured between the CE and all attached PEs1.
Verified References: Ethernet Virtual Private Networks (EVPNs)
NEW QUESTION # 27
Which of the following best describes the operation of a non-designated forwarder (non-DF) in a single-active Ethernet segment?
- A. Allows Tx unicast, allows Rx unicast, blocks Tx BUM, allows Rx BUM
- B. Allows Tx unicast, blocks Rx unicast, allows Tx BUM, blocks Rx BUM
- C. Blocks Tx unicast, allows Rx unicast, blocks Tx BUM, allows Rx BUM
- D. Blocks Tx unicast, blocks Rx unicast, blocks Tx BUM, blocks Rx BUM
Answer: C
Explanation:
A non-designated forwarder (non-DF) in a single-active Ethernet segment blocks Tx unicast, allows Rx unicast, blocks Tx BUM, and allows Rx BUM.
This prevents traffic duplication and ensures that only the DF forwards traffic to and from the CE.
NEW QUESTION # 28
Which of the following statements about the EVPN route types used to support multi-homing is TRUE?
- A. A-D per Ethernet segment routes indicate the desired designated forwarder election algorithm.
- B. Ethernet segment (ES) routes indicate the redundancy mode of the Ethernet segment.
- C. ES routes provide the ESI label required to support the split-horizon mechanism.
- D. Auto-discovery (A-D) routes are imported by all PES participating in the EVPN service.
Answer: B
Explanation:
Explanation
Ethernet segment (ES) routes indicate the redundancy mode of the Ethernet segment. The redundancy mode can be either single-active or all-active, and it determines how traffic is forwarded to and from a multi-homed CE1.
Verified References: Ethernet Virtual Private Networks (EVPNs)
NEW QUESTION # 29
Which of the following statements about the EVPN data plane is FALSE?
- A. EVPN-MPLS encapsulated data has a label that uniquely identifies each service.
- B. EVPN allows a service provider to deliver multiple services over a single core network.
- C. The customer data is encapsulated and then tunneled between the PE routers.
- D. EVPN-MPLS provides services over a simple IP network.
Answer: D
Explanation:
Explanation
EVPN-MPLS provides services over an MPLS network, not a simple IP network. The customer data is encapsulated with an MPLS label that identifies the service and then tunneled between the PE routers using MPLS LSPs1.
Verified References: Ethernet Virtual Private Networks (EVPNs)
NEW QUESTION # 30
Proxy-ARP/ND is operational for a VPLS. Which of the following statements is FALSE?
- A. The PE advertises a MAC/IP route that includes the MAC and IP address of a local host.
- B. When the PE learns a local host IP address, it adds an entry into its proxy-ARP table.
- C. The PE has proxy-ARP and dynamic-populate enabled for the VPLS.
- D. The proxy-ARP table is populated by snooping IP packets received from remote PEs.
Answer: B
Explanation:
Explanation
When the PE learns a local host IP address, it does not add an entry into its proxy-ARP table. The proxy-ARP table is populated by snooping IP packets received from remote PEs. The PE advertises a MAC/IP route that includes the MAC and IP address of a local host.
NEW QUESTION # 31
A Layer-3 EVPN service is configured to use the interface-ful unnumbered forwarding model. Which of the following statements isFALSE?
- A. The VPRN service is configured to allow the advertisement of IP prefixes.
- B. The SBD IRB interface configured in the VPRN service has no IP address assigned to it.
- C. IP-Prefix routes exchanged between PES include a non-zero MAC address as an overlay index.
- D. Each participating PE advertises a MAC/IP route that carries the MAC address of SBD IRB interface.
Answer: B
Explanation:
Explanation
The SBD IRB interface configured in the VPRN service has an IP address assigned to it. The IP address is used as a gateway IP address for hosts in the corresponding subnet2.
Verified References: Nokia Ethernet Virtual Private Network Services Course | Nokia
NEW QUESTION # 32
Which of the following statements about EVPN Layer-3 services that utilize the interface-ful model is TRUE?
- A. Intra-subnet traffic is carried over the tunnels provided by the SBD VPLS.
- B. EVPN MAC/IP routes are used to advertise the IP prefixes of subnets attached to a VPRN.
- C. The MAC/IP routing information is used to populate the VPRN routing table at the remote PEs.
- D. VPRN instances are interconnected using a supplementary broadcast domain (SBD) VPLS.
Answer: A
Explanation:
Explanation
In the interface-ful model, VPRN instances are interconnected using a supplementary broadcast domain (SBD) VPLS. Intra-subnet traffic is carried over the tunnels provided by the SBD VPLS. The MAC/IP routing information is not used to populate the VPRN routing table at the remote PEs, but rather to populate the FDB of the SBD VPLS2.
Verified References: Nokia Ethernet Virtual Private Network Services Course | Nokia
NEW QUESTION # 33
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