Cisco 350-501 Practice Test 47
Question 460
For an original SPCOR service-provider engineering scenario, consider: An EVPN PE can reach the remote loopback but a new customer MAC never appears at the other PE because the expected EVPN type-2 route is absent. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Change: Build selective route leaking or shared-service VRF connectivity with scoped route targets and explicit security controls for shared and internet paths.
- Treat any BGP IPv4 unicast route as an automatic EVPN MAC advertisement without configuring the EVPN address family.
- Change: Advertise and import the proper EVPN MAC or IP reachability route type and associated route targets for the requested L2 or L3 service.
- Check: Trace VPNv4 advertisements, ASBR or RR roles, per-hop label stack and route-target import on a two-AS test topology.
- Check: Check EVPN address-family advertisements, route types, Ethernet segment and EVI context, route targets and remote forwarding database.
Explanation
Correct Answer
C:Acceptance: Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances. Applied case: An EVPN PE can reach the remote loopback but a new customer MAC never appears at the other PE because the expected EVPN type-2 route is absent.
E:Acceptance: Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
Incorrect Answers
A:Change: Build selective route leaking or shared-service VRF connectivity with scoped route targets and explicit security controls for shared and internet paths. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
B:EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions. Use this instead: Advertise and import the proper EVPN MAC or IP reachability route type and associated route targets for the requested L2 or L3 service.
D:Check: Trace VPNv4 advertisements, ASBR or RR roles, per-hop label stack and route-target import on a two-AS test topology. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
Question 461
A service provider network engineer is reviewing this backbone or customer-service scenario: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate. A proposed shortcut is: Treat any BGP IPv4 unicast route as an automatic EVPN MAC advertisement without configuring the EVPN address family. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Advertise and import the proper EVPN MAC or IP reachability route type and associated route targets for the requested L2 or L3 service.
- Match ingress encapsulation, symmetric tag rewrite and EVC service instances to the contracted UNI format end to end.
- Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale.
- Treat any BGP IPv4 unicast route as an automatic EVPN MAC advertisement without configuring the EVPN address family.
Explanation
Correct Answer
A:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate.
Incorrect Answers
B:Match ingress encapsulation, symmetric tag rewrite and EVC service instances to the contracted UNI format end to end. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
C:Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
D:EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions. Applied case: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate.
Question 462
A Cisco service provider design review finds: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate. The team proposes: Advertise and import the proper EVPN MAC or IP reachability route type and associated route targets for the requested L2 or L3 service. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network.
- Carrier supporting carrier lets a provider transport another carrier's VPN or MPLS reachability without needing full visibility into every downstream end-customer route.
- EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
- L3VPN extranet services require controlled cross-VRF routing and return reachability; sharing a few service routes need not grant full tenant-to-tenant visibility.
Explanation
Correct Answer
C:Demonstrable success requires: Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances. Applied case: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate.
Incorrect Answers
A:IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
B:Carrier supporting carrier lets a provider transport another carrier's VPN or MPLS reachability without needing full visibility into every downstream end-customer route. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
D:L3VPN extranet services require controlled cross-VRF routing and return reachability; sharing a few service routes need not grant full tenant-to-tenant visibility. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
Question 463
The service provider operations team has not yet approved a change. Current evidence indicates: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC.
- Check EVPN address-family advertisements, route types, Ethernet segment and EVI context, route targets and remote forwarding database.
- Inspect (*,G) and (S,G) state, RP mapping, RPF interface and actual receiver joins under a test stream.
- Trace VPNv4 advertisements, ASBR or RR roles, per-hop label stack and route-target import on a two-AS test topology.
Explanation
Correct Answer
B:Confirm afterward that: Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances. Applied case: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate.
Incorrect Answers
A:Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
C:Inspect (*,G) and (S,G) state, RP mapping, RPF interface and actual receiver joins under a test stream. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
D:Trace VPNv4 advertisements, ASBR or RR roles, per-hop label stack and route-target import on a two-AS test topology. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
Question 464
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate. The carrier operations owner needs positive and negative tests showing existing customer services remain available. Which acceptance result demonstrates correct service provider forwarding and control behavior without disrupting authorized workflows? Select ONE best answer.
- Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances.
- The ring remains loop-free at steady state and service recovers through the allowed protection topology with traceable alarms.
- The dual-homed customer retains connectivity with correct single-copy flooding and no persistent Layer-2 forwarding loops.
- Subscribers receive only authorized group and source traffic with no unnecessary replication to idle access ports.
Explanation
Correct Answer
A:EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions. The result must be validated using the documented device, service or access context.
Incorrect Answers
B:The ring remains loop-free at steady state and service recovers through the allowed protection topology with traceable alarms. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
C:The dual-homed customer retains connectivity with correct single-copy flooding and no persistent Layer-2 forwarding loops. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
D:Subscribers receive only authorized group and source traffic with no unnecessary replication to idle access ports. EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
Question 465
An implementation sign-off request identifies the following problem: A VXLAN or MPLS EVPN service needs routed prefix exchange but the operator advertises only Ethernet MAC reachability and expects L3 tenant prefixes to propagate. Which paired technical change and validation should close the implementation review? Select ONE best answer.
- Change: Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability. Verify: Examine VRF route tables, RD, RT extended communities, MP-BGP updates and the transport plus VPN label stack.
- Change: Match the Ethernet service type to required point-to-point, multipoint or rooted traffic relationships and enforce the appropriate endpoint split rules. Verify: Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC.
- Change: Advertise and import the proper EVPN MAC or IP reachability route type and associated route targets for the requested L2 or L3 service. Verify: Check EVPN address-family advertisements, route types, Ethernet segment and EVI context, route targets and remote forwarding database.
- Change: Build the supported carrier-supporting-carrier transport and routing boundary, retaining customer-carrier control where intended and validating labeled reachability. Verify: Check labeled route handoff, VRF or transport separation, next-hop reachability and a representative downstream customer LSP.
Explanation
Correct Answer
C:The change is successful only when: Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances.
Incorrect Answers
A:Change: Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability.
B:Change: Match the Ethernet service type to required point-to-point, multipoint or rooted traffic relationships and enforce the appropriate endpoint split rules.
D:Change: Build the supported carrier-supporting-carrier transport and routing boundary, retaining customer-carrier control where intended and validating labeled reachability.
Question 466
A service provider network engineer is reviewing this backbone or customer-service scenario: A customer CE is dual-homed to two EVPN PEs but a network loop develops because both forward the same flooded frame back into the Ethernet segment. A proposed shortcut is: Give each multihomed PE a different arbitrary ESI and bridge all customer packets without loop prevention. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Give each multihomed PE a different arbitrary ESI and bridge all customer packets without loop prevention.
- Configure a consistent Ethernet Segment Identifier and supported designated-forwarder or split-horizon behavior for the multihoming model.
- Enable supported ring protection and Ethernet OAM mechanisms to enforce a loop-free normal state and verify service continuity after failure.
- Match ingress encapsulation, symmetric tag rewrite and EVC service instances to the contracted UNI format end to end.
Explanation
Correct Answer
B:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: A customer CE is dual-homed to two EVPN PEs but a network loop develops because both forward the same flooded frame back into the Ethernet segment.
Incorrect Answers
A:EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability. For this best change assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it.
C:Enable supported ring protection and Ethernet OAM mechanisms to enforce a loop-free normal state and verify service continuity after failure. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
D:Match ingress encapsulation, symmetric tag rewrite and EVC service instances to the contracted UNI format end to end. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
Question 467
A Cisco service provider design review finds: A customer CE is dual-homed to two EVPN PEs but a network loop develops because both forward the same flooded frame back into the Ethernet segment. The team proposes: Configure a consistent Ethernet Segment Identifier and supported designated-forwarder or split-horizon behavior for the multihoming model. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- G.8032 Ethernet Ring Protection controls blocked and active ring links, while Ethernet OAM provides fault detection and service continuity evidence.
- EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
- E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
- EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions.
Explanation
Correct Answer
B:Demonstrable success requires: The dual-homed customer retains connectivity with correct single-copy flooding and no persistent Layer-2 forwarding loops. Applied case: A customer CE is dual-homed to two EVPN PEs but a network loop develops because both forward the same flooded frame back into the Ethernet segment.
Incorrect Answers
A:G.8032 Ethernet Ring Protection controls blocked and active ring links, while Ethernet OAM provides fault detection and service continuity evidence. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
C:E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
D:EVPN uses MP-BGP to signal Ethernet MAC or IP reachability and other service state; type-2 and type-5 serve different reachability functions. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
Question 468
The service provider operations team has not yet approved a change. Current evidence indicates: A customer CE is dual-homed to two EVPN PEs but a network loop develops because both forward the same flooded frame back into the Ethernet segment. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Inspect IGMPv3 source lists or MLD reports, snooping table, receiver membership and forwarded multicast stream source identities.
- Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers.
- Check labeled route handoff, VRF or transport separation, next-hop reachability and a representative downstream customer LSP.
- Compare ESI advertisements, DF election, MAC mobility sequence and traffic behavior before and after one PE uplink failure.
Explanation
Correct Answer
D:EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability. Applied case: A customer CE is dual-homed to two EVPN PEs but a network loop develops because both forward the same flooded frame back into the Ethernet segment.
Incorrect Answers
A:Inspect IGMPv3 source lists or MLD reports, snooping table, receiver membership and forwarded multicast stream source identities. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
B:Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
C:Check labeled route handoff, VRF or transport separation, next-hop reachability and a representative downstream customer LSP. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
Question 469
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A customer CE is dual-homed to two EVPN PEs but a network loop develops because both forward the same flooded frame back into the Ethernet segment. The carrier operations owner needs positive and negative tests showing existing customer services remain available. Which acceptance result demonstrates correct service provider forwarding and control behavior without disrupting authorized workflows? Select ONE best answer.
- Intended subscribers receive the selected source and nonmembers do not trigger unwanted flood or RP dependence.
- The dual-homed customer retains connectivity with correct single-copy flooding and no persistent Layer-2 forwarding loops.
- Customers reach only approved shared services and internet egress while peer-to-peer tenant access remains restricted.
- Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources.
Explanation
Correct Answer
B:EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability. The result must be validated using the documented device, service or access context.
Incorrect Answers
A:Intended subscribers receive the selected source and nonmembers do not trigger unwanted flood or RP dependence. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
C:Customers reach only approved shared services and internet egress while peer-to-peer tenant access remains restricted. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
D:Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
Question 470
For an original SPCOR service-provider engineering scenario, consider: A customer CE is dual-homed to two EVPN PEs but a network loop develops because both forward the same flooded frame back into the Ethernet segment. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Check: Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC.
- Change: Configure a consistent Ethernet Segment Identifier and supported designated-forwarder or split-horizon behavior for the multihoming model.
- Check: Compare ESI advertisements, DF election, MAC mobility sequence and traffic behavior before and after one PE uplink failure.
- Give each multihomed PE a different arbitrary ESI and bridge all customer packets without loop prevention.
- Change: Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping.
Explanation
Correct Answer
B:EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability. Evidence: Compare ESI advertisements, DF election, MAC mobility sequence and traffic behavior before and after one PE uplink failure.
C:EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability. Required intervention: Configure a consistent Ethernet Segment Identifier and supported designated-forwarder or split-horizon behavior for the multihoming model.
Incorrect Answers
A:Check: Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
D:For this select two assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
E:Change: Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping. EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability.
