Cisco 350-501 Practice Test 52
Question 510
For an original SPCOR service-provider engineering scenario, consider: A customer buys a private E-Line between two sites yet the provisioner adds a third site to the same shared bridging service. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Deploy a common unfiltered bridge domain for every customer and label it E-Tree without testing leaf restrictions.
- Change: Match multicast routing mode and receiver source selection, then verify PIM RPF and RP or source-tree behavior for the chosen model.
- Check: Inspect customer PIM state, mVPN BGP or tree signaling, receiver joins, replication counters and stream reachability between PEs.
- Change: Match the Ethernet service type to required point-to-point, multipoint or rooted traffic relationships and enforce the appropriate endpoint split rules.
- Check: Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC.
Explanation
Correct Answer
D:Acceptance: Permitted locations communicate according to the contracted Ethernet service while disallowed leaf or tenant pairs remain isolated. Applied case: A customer buys a private E-Line between two sites yet the provisioner adds a third site to the same shared bridging service.
E:Acceptance: Permitted locations communicate according to the contracted Ethernet service while disallowed leaf or tenant pairs remain isolated. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
Incorrect Answers
A:E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions. Use this instead: Match the Ethernet service type to required point-to-point, multipoint or rooted traffic relationships and enforce the appropriate endpoint split rules.
B:Change: Match multicast routing mode and receiver source selection, then verify PIM RPF and RP or source-tree behavior for the chosen model. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
C:Check: Inspect customer PIM state, mVPN BGP or tree signaling, receiver joins, replication counters and stream reachability between PEs. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
Question 511
A service provider network engineer is reviewing this backbone or customer-service scenario: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN. A proposed shortcut is: Deploy a common unfiltered bridge domain for every customer and label it E-Tree without testing leaf restrictions. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Build the supported carrier-supporting-carrier transport and routing boundary, retaining customer-carrier control where intended and validating labeled reachability.
- Advertise and import the proper EVPN MAC or IP reachability route type and associated route targets for the requested L2 or L3 service.
- Deploy a common unfiltered bridge domain for every customer and label it E-Tree without testing leaf restrictions.
- Match the Ethernet service type to required point-to-point, multipoint or rooted traffic relationships and enforce the appropriate endpoint split rules.
Explanation
Correct Answer
D:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN.
Incorrect Answers
A:Build the supported carrier-supporting-carrier transport and routing boundary, retaining customer-carrier control where intended and validating labeled reachability. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
B:Advertise and import the proper EVPN MAC or IP reachability route type and associated route targets for the requested L2 or L3 service. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
C:E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions. Applied case: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN.
Question 512
A Cisco service provider design review finds: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN. The team proposes: Match the Ethernet service type to required point-to-point, multipoint or rooted traffic relationships and enforce the appropriate endpoint split rules. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- PIM-SM may use a rendezvous point for shared-tree discovery, while SSM uses explicit source-group state and normally avoids RP discovery.
- 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.
- A route distinguisher makes overlapping VPN routes uniquely identifiable, whereas route targets control membership and distribution of VPN routing information.
Explanation
Correct Answer
C:Demonstrable success requires: Permitted locations communicate according to the contracted Ethernet service while disallowed leaf or tenant pairs remain isolated. Applied case: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN.
Incorrect Answers
A:PIM-SM may use a rendezvous point for shared-tree discovery, while SSM uses explicit source-group state and normally avoids RP discovery. A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN.
B:EVPN multihoming coordinates PE participation through Ethernet segment routes and forwarder election to prevent loops and maintain reachability. A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN.
D:A route distinguisher makes overlapping VPN routes uniquely identifiable, whereas route targets control membership and distribution of VPN routing information. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
Question 513
The service provider operations team has not yet approved a change. Current evidence indicates: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Compare ESI advertisements, DF election, MAC mobility sequence and traffic behavior before and after one PE uplink failure.
- Inspect customer PIM state, mVPN BGP or tree signaling, receiver joins, replication counters and stream reachability between PEs.
- Compare imported RT lists, VRF next hops, shared service return routing and firewall policy using two customer tenants.
- Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC.
Explanation
Correct Answer
D:Confirm afterward that: Permitted locations communicate according to the contracted Ethernet service while disallowed leaf or tenant pairs remain isolated. Applied case: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN.
Incorrect Answers
A:Compare ESI advertisements, DF election, MAC mobility sequence and traffic behavior before and after one PE uplink failure. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
B:Inspect customer PIM state, mVPN BGP or tree signaling, receiver joins, replication counters and stream reachability between PEs. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
C:Compare imported RT lists, VRF next hops, shared service return routing and firewall policy using two customer tenants. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
Question 514
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN. 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 devices receive frames in the specified tagging format and service VLANs remain separated despite provider translations.
- Each customer's original VLAN identity is preserved or intentionally translated and service isolation remains intact across the provider.
- Each customer reaches only its own remote sites despite overlapping addresses and the expected VPN routes import correctly.
- Permitted locations communicate according to the contracted Ethernet service while disallowed leaf or tenant pairs remain isolated.
Explanation
Correct Answer
D:E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions. The result must be validated using the documented device, service or access context.
Incorrect Answers
A:Customer devices receive frames in the specified tagging format and service VLANs remain separated despite provider translations. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
B:Each customer's original VLAN identity is preserved or intentionally translated and service isolation remains intact across the provider. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
C:Each customer reaches only its own remote sites despite overlapping addresses and the expected VPN routes import correctly. A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN.
Question 515
An implementation sign-off request identifies the following problem: A cloud access aggregator needs rooted multipoint E-Tree connectivity that prevents leaf-to-leaf traffic but deploys an unrestricted E-LAN. Which paired technical change and validation should close the implementation review? Select ONE best answer.
- 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: 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: Use matching IGMP or MLD listener protocols and supported source-filtering behavior on the appropriate IPv4 or IPv6 access segment. Verify: Inspect IGMPv3 source lists or MLD reports, snooping table, receiver membership and forwarded multicast stream source identities.
- Change: Select the supported Inter-AS VPN option and validate labeled VPN route exchange, route targets and transport next-hop resolution at each boundary. Verify: Trace VPNv4 advertisements, ASBR or RR roles, per-hop label stack and route-target import on a two-AS test topology.
Explanation
Correct Answer
A:The change is successful only when: Permitted locations communicate according to the contracted Ethernet service while disallowed leaf or tenant pairs remain isolated.
Incorrect Answers
B:Change: Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
C:Change: Use matching IGMP or MLD listener protocols and supported source-filtering behavior on the appropriate IPv4 or IPv6 access segment. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
D:Change: Select the supported Inter-AS VPN option and validate labeled VPN route exchange, route targets and transport next-hop resolution at each boundary. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
Question 516
A service provider network engineer is reviewing this backbone or customer-service scenario: A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink. A proposed shortcut is: Remove every customer C-tag at the carrier boundary and assume an outer shared S-tag preserves all separate customer VLANs. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability.
- Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping.
- Remove every customer C-tag at the carrier boundary and assume an outer shared S-tag preserves all separate customer VLANs.
- Match multicast routing mode and receiver source selection, then verify PIM RPF and RP or source-tree behavior for the chosen model.
Explanation
Correct Answer
B:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network.
Incorrect Answers
A:Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability. IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network.
C:IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network. For this best change assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it.
D:Match multicast routing mode and receiver source selection, then verify PIM RPF and RP or source-tree behavior for the chosen model. IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network.
Question 517
A Cisco service provider design review finds: A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink. The team proposes: Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping. 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.
- A route distinguisher makes overlapping VPN routes uniquely identifiable, whereas route targets control membership and distribution of VPN routing information.
- G.8032 Ethernet Ring Protection controls blocked and active ring links, while Ethernet OAM provides fault detection and service continuity evidence.
- Inter-AS L3VPN designs extend VPN signaling across AS boundaries with option-specific control-plane and label requirements; route visibility does not alone prove data-plane continuity.
Explanation
Correct Answer
A:Demonstrable success requires: Each customer's original VLAN identity is preserved or intentionally translated and service isolation remains intact across the provider. This principle explains the proposed technical approach, which is: Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping.
Incorrect Answers
B:A route distinguisher makes overlapping VPN routes uniquely identifiable, whereas route targets control membership and distribution of VPN routing information. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
C:G.8032 Ethernet Ring Protection controls blocked and active ring links, while Ethernet OAM provides fault detection and service continuity evidence. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
D:Inter-AS L3VPN designs extend VPN signaling across AS boundaries with option-specific control-plane and label requirements; route visibility does not alone prove data-plane continuity. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
Question 518
The service provider operations team has not yet approved a change. Current evidence indicates: A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers.
- Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC.
- Check labeled route handoff, VRF or transport separation, next-hop reachability and a representative downstream customer LSP.
- Trace VPNv4 advertisements, ASBR or RR roles, per-hop label stack and route-target import on a two-AS test topology.
Explanation
Correct Answer
A:IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network. Applied case: A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
Incorrect Answers
B:Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
C:Check labeled route handoff, VRF or transport separation, next-hop reachability and a representative downstream customer LSP. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
D:Trace VPNv4 advertisements, ASBR or RR roles, per-hop label stack and route-target import on a two-AS test topology. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
Question 519
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink. 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.
- Subscribers receive only authorized group and source traffic with no unnecessary replication to idle access ports.
- Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances.
- Customers reach only approved shared services and internet egress while peer-to-peer tenant access remains restricted.
- Each customer's original VLAN identity is preserved or intentionally translated and service isolation remains intact across the provider.
Explanation
Correct Answer
D:IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network. The result must be validated using the documented device, service or access context.
Incorrect Answers
A:Subscribers receive only authorized group and source traffic with no unnecessary replication to idle access ports. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
B:Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
C:Customers reach only approved shared services and internet egress while peer-to-peer tenant access remains restricted. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
Question 520
For an original SPCOR service-provider engineering scenario, consider: A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Check: Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers.
- Check: Inspect IGMPv3 source lists or MLD reports, snooping table, receiver membership and forwarded multicast stream source identities.
- Change: Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale.
- Change: Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping.
- Remove every customer C-tag at the carrier boundary and assume an outer shared S-tag preserves all separate customer VLANs.
Explanation
Correct Answer
A:IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network. Required intervention: Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping.
D:IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network. Evidence: Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers.
Incorrect Answers
B:Check: Inspect IGMPv3 source lists or MLD reports, snooping table, receiver membership and forwarded multicast stream source identities. IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network.
C:Change: Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale. A metro PE strips the customer's inner VLAN tag when applying a service VLAN, so two different customer services are merged on an uplink.
E:For this select two assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it. IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network.
