10 free Cisco 300-515 SPVI practice questions with the correct answer and a full explanation for each, taken from the CertStash pack of 147 questions. Work through them, then open each answer to check your reasoning.
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Question 1
Which utility can you use to validate an LSP in an MPLS environment?
Show answer and explanation
Correct answer: B. MPLS LSP ping
MPLS LSP ping (also called ping MPLS) is a diagnostic utility specifically designed to validate Label Switched Paths in MPLS environments. It verifies end-to-end connectivity and proper label forwarding along an LSP by sending specially crafted MPLS echo requests and receiving responses.
Why the other options are wrong
- A. uRPF (Unicast Reverse Path Forwarding) is a security mechanism to prevent spoofed packets, not an LSP validation tool.
- C. Logging is a monitoring and recording feature that does not actively validate LSP connectivity.
- D. RSVP is a signaling protocol used to establish LSPs, not a validation utility for testing them.
Question 2
What is the primary function of a VRF on a router?
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Correct answer: A. It enables the router to support multiple separate routing tables, which allows the device to handle overlapping IP addresses.
Virtual Routing and Forwarding (VRF) enables a router to maintain multiple independent routing tables simultaneously, allowing it to support overlapping IP address spaces as each VRF maintains its own separate forwarding domain. This is fundamental to MPLS VPN implementations.
Why the other options are wrong
- B. While VRFs can be used in VPN environments, the primary function is not about running different routing protocol types together, and this description conflates multiple concepts.
- C. VRF is a Layer 3 routing feature, not related to VLAN configuration which operates at Layer 2.
- D. Label switching and interface identification are MPLS functions, not the primary purpose of VRFs.
Question 3
Refer to the exhibit. A network engineer has been called to configure the four PE devices in order to enable full communication among the four CE devices connected to them. While starting to configure, he experienced a connectivity issue.
Which two tasks should the engineer perform in order to begin the process correctly? (Choose two.)
Show answer and explanation
Correct answer: B, E
B. Configure PE3 to import route-targets 100:1 and 200:2. E. Configure PE1 to import route-targets 300:3 and 400:4. In MPLS VPN networks, route-targets control which routes are imported and exported between PE devices. For full connectivity among all four CEs, each PE must be able to receive routes from the other PEs that have customer routes destined for its own customers. PE3 currently exports 300:3 and imports 400:4, but PE1 and PE2 export 100:1 and 200:2 respectively. PE3 needs to import these route-targets (100:1 and 200:2) to receive routes from PE1 and PE2, making option B correct. Similarly, PE4 currently exports 400:4 and imports 300:3, but needs to import 101:1 and 202:2 to receive the routes exported by PE1 and PE2 respectively, making option C correct. Wait, reviewing again: PE2 exports 200:2 and PE1 exports 100:1. PE4 imports 300:3 but needs to also import what PE1 and PE2 export. Option C states PE4 should import 101:1 and 202:2, but PE1 exports 100:1 (not 101:1) and PE2 exports 200:2 (not 202:2). However, reviewing the RD values: PE1 has rd 101:1 and PE2 has rd 202:2. The route-targets should match the exports. PE4 should import 100:1 and 200:2 to match PE1 and PE2's exports. Option B (PE3 imports 100:1 and 200:2) is correct. Option E (PE1 imports 300:3 and 400:4) allows PE1 to receive routes from PE3 and PE4. These are the two missing configurations needed for full mesh connectivity.
Why the other options are wrong
- A. PE3 should import these route-targets to receive routes, not export them; exporting 100:1 and 200:2 would create incorrect route distribution.
- C. PE4 should import 100:1 and 200:2 (matching PE1 and PE2's exports), not 101:1 and 202:2 which are route distinguishers, not route-targets.
- D. PE2 already has the correct export configuration (200:2) and doesn't need to export 300:3 and 400:4 which belong to PE3 and PE4.
Question 4
Refer to the exhibit. If the two devices are operating normally, which two conclusions can you draw from this configuration? (Choose two.)
Show answer and explanation
Correct answer: B, D
B. PE1 labels the routes it learns from CE1 with the route-target 222:2 and shares them with its VPNv4 peers. D. The PE-CE routes between the devices are being exchanged by OSPF In this MPLS VPN configuration, PE1 and CE1 exchange PE-CE routes using OSPF as the routing protocol. PE1 has 'router ospf 1 vrf celvpn' with network 192.168.0.0/24 area 1, and CE1 has 'router ospf 100' with network 192.168.0.0/24 area1, establishing an OSPF neighbor relationship. The route-target 222:2 is configured as the export policy on PE1 (route-target export 111:1 means it imports routes with 111:1, while it exports with 222:2 implicitly for this VRF context), which means routes learned from CE1 are labeled with 222:2 when shared with other PE routers. Option B is correct because PE1 uses the export route-target to tag routes learned from CE1 before distributing them. Option D is correct because the PE-CE routing exchange between the two devices occurs via OSPF, not BGP.
Why the other options are wrong
- A. CE1 does not need to use OSPF to establish a neighbor relationship with PE1; they already have OSPF running and established as the PE-CE routing protocol.
- C. Route-target 111:1 is imported by PE1, not exported; PE1 exports routes with 222:2 to other VPNv4 peers.
- E. Carrier Supporting Carrier (CSC) is not indicated in this configuration; the setup shows a standard MPLS VPN with VRF-based routing.
Question 5
In an Ethernet Virtual Circuit environment, which restriction do bridge domains have when STP is running?
Show answer and explanation
Correct answer: D. Bridge domains must belong to different MST instances.
In an Ethernet Virtual Circuit environment with STP running, bridge domains must belong to different MST (Multiple Spanning Tree) instances to prevent spanning tree conflicts and ensure proper loop prevention across multiple bridge domains on the same service.
Why the other options are wrong
- A. While RSTP and PVST+ are STP modes, they are not specific restrictions for EVC bridge domains; MSTP is the correct answer.
- B. Bridge domains in EVC are logical constructs that may map to VLANs, but the restriction is about MST instances, not VLAN mapping requirements.
- C. Although MSTP is involved, the restriction is that domains must belong to different instances, not that the mode must be MSTP exclusively.
Question 6
Refer to the exhibit. An engineer is implementing an MPLS P2MP TE solution.
Which type of router can serve as the midpoint router and the tailend router in this P2MP TE network implementation?
Show answer and explanation
Correct answer: C. transit
In MPLS Point-to-Multipoint (P2MP) Traffic Engineering, a transit router (also called a midpoint router) is positioned between the headend and tailend routers. Transit routers forward traffic along the P2MP tree and can also serve as branch points where the tree splits to reach multiple tailends. The diagram shows the midpoint and branch point router forwarding traffic to multiple tailend destinations, which is the defining function of a transit router in P2MP TE topologies.
Why the other options are wrong
- A. The headend is the source originator of the P2MP tree, not a midpoint or tailend router.
- B. Source is synonymous with headend and cannot serve as a midpoint or tailend in the tree topology.
- D. A bud router is a router that functions as both a transit point (forwarding traffic downstream) and a tailend (receiving traffic), not the general midpoint/branch point role described in the exhibit.
Question 7
An engineer is investigating an EVPN traffic flow issue.
Which type of traffic should the engineer allow in an EVPN Tree Service in order to fix this issue?
Show answer and explanation
Correct answer: C. multicast from a leaf to another leaf
EVPN Tree Services are used for multicast and broadcast traffic distribution in EVPN environments. The engineer should allow multicast traffic from a leaf to another leaf to fix traffic flow issues in these services, as multicast is the primary data plane for EVPN tre-ased services.
Why the other options are wrong
- A. Known unicast is standard unicast traffic handled by normal EVPN mechanisms, not tree services.
- B. Unknown unicast (flooding) is not the specific traffic type that EVPN Tree Services are designed to handle.
- D. Root-to-root traffic patterns are not the correct model; EVPN Tree Services operate between leaves for multicast distribution.
Question 8
An engineer is investigating an MPLS LDP issue.
Which command should an engineer use on a Cisco IOS XE device to display the contents of the LFIB?
Show answer and explanation
Correct answer: A. show mpls forwarding-table
The 'show mpls forwarding-table' command displays the Label Forwarding Information Base (LFIB) on Cisco IOS XE devices, showing the actual labels and their outgoing interfaces used for packet forwarding in the MPLS network.
Why the other options are wrong
- B. show mpls ldp neighbors displays LDP peer relationships, not the LFIB contents.
- C. show mpls ldp labels shows label bindings learned through LDP, but not the active forwarding table.
- D. show mpls ldp bindings displays label-to-prefix mappings from LDP, not the operational LFIB used for forwarding.
Question 9
Refer to the exhibit.
Which statement about this output is true?
Show answer and explanation
Correct answer: D. The zero in the second column is the normal behavior of an egress router LSR.
The output shows an MPLS forwarding table where the 'Bytes label switched' column displays 0 for all entries. This is normal behavior for an egress LSR (Label Switching Router). An egress router is the last hop in an MPLS path and removes the MPLS label from packets before forwarding them to the next hop. Since the egress router pops the label and forwards based on the IP header rather than switching labeled packets, it shows zero bytes switched. The other options misinterpret the output: Option A incorrectly references an implicit null from a specific IP address; Option B incorrectly assumes explicit-null configuration based on the zero value in the local outgoing label column; Option C misreads the label range configuration.
Question 10
An engineer is troubleshooting an ongoing network outage.
Which command should he use that can display the live log files for a process or service running on a network device?
Show answer and explanation
Correct answer: D. debug
The 'debug' command displays live log output for processes and services running on a network device in real-time, showing detailed operational information and events as they occur. This is essential for troubleshooting active network issues.
Why the other options are wrong
- A. traceroute is a path discovery tool that shows hops to a destination, not a logging utility.
- B. show run displays the running configuration file, which is static and not live process logs.
- C. ping is a basic connectivity test tool and does not display live process logs.
That was 10 of 147.
The full Cisco 300-515 SPVI pack has all 147 questions, each with the answer, the explanation and why the other options are wrong, plus a questions-only copy for timed runs. US$39, paid once, with free monthly updates and a pass-or-your-money-back guarantee.