Cisco 350-501 Practice Test 51
Question 500
For an original SPCOR service-provider engineering scenario, consider: A customer's multicast video stream crosses an MPLS VPN but the provider builds only unicast VRF routes and expects replication to happen automatically. Select THREE compatible elements: a proper correction, a targeted diagnostic and an acceptance result.
- Result: The ring remains loop-free at steady state and service recovers through the allowed protection topology with traceable alarms.
- Change: Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability.
- Change: Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale.
- Check: Inspect customer PIM state, mVPN BGP or tree signaling, receiver joins, replication counters and stream reachability between PEs.
- Check: Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion.
- Result: Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources.
Explanation
Correct Answer
C:Acceptance: Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources. Applied case: A customer's multicast video stream crosses an MPLS VPN but the provider builds only unicast VRF routes and expects replication to happen automatically.
D:Acceptance: Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
F:MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange. Required intervention: Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale.
Incorrect Answers
A:Result: The ring remains loop-free at steady state and service recovers through the allowed protection topology with traceable alarms. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
B:Change: Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
E:Check: Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
Question 501
A service provider network engineer is reviewing this backbone or customer-service scenario: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth. A proposed shortcut is: Treat every unicast VPN route as an automatic request for multicast delivery to all provider edge routers. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Use matching IGMP or MLD listener protocols and supported source-filtering behavior on the appropriate IPv4 or IPv6 access segment.
- Treat every unicast VPN route as an automatic request for multicast delivery to all provider edge routers.
- Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale.
- 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
C:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth.
Incorrect Answers
A:Use matching IGMP or MLD listener protocols and supported source-filtering behavior on the appropriate IPv4 or IPv6 access segment. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
B:MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange. Applied case: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth.
D:Match the Ethernet service type to required point-to-point, multipoint or rooted traffic relationships and enforce the appropriate endpoint split rules. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
Question 502
A Cisco service provider design review finds: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth. The team proposes: Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
- L3VPN extranet services require controlled cross-VRF routing and return reachability; sharing a few service routes need not grant full tenant-to-tenant visibility.
- MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
- PIM-SM may use a rendezvous point for shared-tree discovery, while SSM uses explicit source-group state and normally avoids RP discovery.
Explanation
Correct Answer
C:Demonstrable success requires: Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources. Applied case: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth.
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. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
B:L3VPN extranet services require controlled cross-VRF routing and return reachability; sharing a few service routes need not grant full tenant-to-tenant visibility. An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth.
D:PIM-SM may use a rendezvous point for shared-tree discovery, while SSM uses explicit source-group state and normally avoids RP discovery. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
Question 503
The service provider operations team has not yet approved a change. Current evidence indicates: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Examine VRF route tables, RD, RT extended communities, MP-BGP updates and the transport plus VPN label stack.
- Compare ESI advertisements, DF election, MAC mobility sequence and traffic behavior before and after one PE uplink failure.
- Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers.
- Inspect customer PIM state, mVPN BGP or tree signaling, receiver joins, replication counters and stream reachability between PEs.
Explanation
Correct Answer
D:Confirm afterward that: Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources. Applied case: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth.
Incorrect Answers
A:Examine VRF route tables, RD, RT extended communities, MP-BGP updates and the transport plus VPN label stack. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
B:Compare ESI advertisements, DF election, MAC mobility sequence and traffic behavior before and after one PE uplink failure. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
C:Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
Question 504
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth. 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 customer carrier preserves its own service topology while the backbone transports authorized labeled traffic without core route explosion.
- Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources.
- Customers reach only approved shared services and internet egress while peer-to-peer tenant access remains restricted.
Explanation
Correct Answer
C:MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange. The result must be validated using the documented device, service or access context.
Incorrect Answers
A:Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
B:The customer carrier preserves its own service topology while the backbone transports authorized labeled traffic without core route explosion. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
D:Customers reach only approved shared services and internet egress while peer-to-peer tenant access remains restricted. An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth.
Question 505
An implementation sign-off request identifies the following problem: An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth. 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 ingress encapsulation, symmetric tag rewrite and EVC service instances to the contracted UNI format end to end. Verify: Capture tagged or untagged frames at both UNIs, check service instance counters and confirm expected VLAN identity after a full round trip.
- Change: Configure the supported mVPN multicast control-plane and provider transport distribution according to receiver membership and traffic scale. Verify: Inspect customer PIM state, mVPN BGP or tree signaling, receiver joins, replication counters and stream reachability between PEs.
- Change: Build selective route leaking or shared-service VRF connectivity with scoped route targets and explicit security controls for shared and internet paths. Verify: Compare imported RT lists, VRF next hops, shared service return routing and firewall policy using two customer tenants.
Explanation
Correct Answer
C:The change is successful only when: Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources.
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. An mVPN source sends to a limited receiver set but the operator uses uncontrolled replication across every PE, consuming unnecessary backbone bandwidth.
B:This option addresses a different service provider engineering topic (EVC VLAN push pop rewrite and service delimiting) rather than the documented Multicast VPN mVPN inclusive and selective trees decision.
D:Change: Build selective route leaking or shared-service VRF connectivity with scoped route targets and explicit security controls for shared and internet paths. MVPN extends multicast services through customer VPN contexts, using signaling and core replication trees distinct from ordinary unicast VPN route exchange.
Question 506
A service provider network engineer is reviewing this backbone or customer-service scenario: A customer buys a private E-Line between two sites yet the provisioner adds a third site to the same shared bridging service. 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.
- Match ingress encapsulation, symmetric tag rewrite and EVC service instances to the contracted UNI format end to end.
- 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.
- Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping.
Explanation
Correct Answer
C:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. 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.
Incorrect Answers
A:Match ingress encapsulation, symmetric tag rewrite and EVC service instances to the contracted UNI format end to end. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
B:E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions. For this best change assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it.
D:Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
Question 507
A Cisco service provider design review finds: A customer buys a private E-Line between two sites yet the provisioner adds a third site to the same shared bridging service. 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.
- EVC tag operations such as push pop and translation are contextual to a service instance and may require symmetric rewrite at both attachment points.
- 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.
- PIM-SM may use a rendezvous point for shared-tree discovery, while SSM uses explicit source-group state and normally avoids RP discovery.
Explanation
Correct Answer
B:Demonstrable success requires: 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.
Incorrect Answers
A:EVC tag operations such as push pop and translation are contextual to a service instance and may require symmetric rewrite at both attachment points. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
C: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.
D:PIM-SM may use a rendezvous point for shared-tree discovery, while SSM uses explicit source-group state and normally avoids RP discovery. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
Question 508
The service provider operations team has not yet approved a change. Current evidence indicates: A customer buys a private E-Line between two sites yet the provisioner adds a third site to the same shared bridging service. 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.
- Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion.
- Inspect (*,G) and (S,G) state, RP mapping, RPF interface and actual receiver joins under a test stream.
Explanation
Correct Answer
A:Confirm afterward that: 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.
Incorrect Answers
B:Check EVPN address-family advertisements, route types, Ethernet segment and EVI context, route targets and remote forwarding database. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
C:Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
D:Inspect (*,G) and (S,G) state, RP mapping, RPF interface and actual receiver joins under a test stream. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
Question 509
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A customer buys a private E-Line between two sites yet the provisioner adds a third site to the same shared bridging service. 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.
- The dual-homed customer retains connectivity with correct single-copy flooding and no persistent Layer-2 forwarding loops.
- Permitted locations communicate according to the contracted Ethernet service while disallowed leaf or tenant pairs remain isolated.
- Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources.
- Each customer reaches only its own remote sites despite overlapping addresses and the expected VPN routes import correctly.
Explanation
Correct Answer
B: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 customer buys a private E-Line between two sites yet the provisioner adds a third site to the same shared bridging service.
Incorrect Answers
A:The dual-homed customer retains connectivity with correct single-copy flooding and no persistent Layer-2 forwarding loops. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
C:Only authorized receiving VPN sites get the multicast data and replication uses the intended provider transport resources. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
D:Each customer reaches only its own remote sites despite overlapping addresses and the expected VPN routes import correctly. E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
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.
