Free Cisco 350-501 Practice Questions 2026 | Implementing and Operating Cisco Service Provider Network Core Technologies (350-501 SPCOR)

Explanation

In OSPF, the Designated Router (DR) and Backup Designated Router (BDR) election occurs on broadcast and non-broadcast network types. To eliminate the DR/BDR election entirely, the interface must be configured with a network type that does not require a DR/BDR. The point-to-point network type does not perform DR/BDR election because it assumes only two routers on the link, making the election unnecessary. Therefore, configuring `ip ospf network point-to-point` on the interfaces removes the DR/BDR election. This makes option B the correct answer.

Why the other options are incorrect:

A. ip ospf network broadcast on interfaces running OSPF – Broadcast is the default network type on Ethernet interfaces and does perform DR/BDR election. This does not remove the election.

C. ip ospf network multipoint-point on interfaces running OSPF – This is not a valid OSPF network type. The correct term is point-to-multipoint, which also does not perform DR/BDR election, but the syntax in this option is incorrect.

D. ip ospf network non-broadcast on interfaces running OSPF – Non-broadcast network type does perform DR/BDR election and requires manual neighbor configuration. It does not remove the election.

Reference:
RFC 2328 – OSPF Version 2; Cisco IOS XR Routing Configuration Guide – Implementing OSPF: Network Types and DR/BDR Election; Cisco 350-501 SPCOR Official Cert Guide, OSPF chapter.

Explanation

Non-Stop Routing (NSR) with OSPF requires that the active and standby Route Processors (RPs) synchronize their OSPF state information before a switchover occurs. This synchronization ensures that the standby RP has the complete OSPF database, neighbor adjacencies, and routing state so that when a switchover happens, the standby RP can take over immediately without disrupting OSPF adjacencies or traffic forwarding. To complete the NSR implementation with minimal disruption, the engineer must ensure that the dual RPs have synchronized their state information before performing the switchover operation. This makes option D the correct answer.

Why the other options are incorrect:

A. Reset OSPF neighbor sessions to maintain state information during router switchover – Resetting OSPF neighbor sessions would cause disruption and defeat the purpose of NSR, which is to avoid neighbor resets and maintain state during switchover.

B. Configure the device to repopulate state information using routing updates received from the BDR – NSR does not repopulate state from the BDR. It synchronizes state internally between the active and standby RPs. Repopulating from routing updates would be slow and disruptive.

C. Increase the keepalive interval on the OSPF neighbors so that traffic continues to pass during the switchover – Increasing the keepalive interval does not provide NSR. NSR maintains adjacencies through internal state synchronization, not by extending timers.

Reference:
Cisco IOS XR High Availability Configuration Guide – Non-Stop Routing (NSR) with OSPF; Cisco 350-501 SPCOR Official Cert Guide, Network Assurance and High Availability sections.

Explanation

To ensure that traffic traverses MPLS TE tunnels, the engineer can use either forwarding adjacency or autoroute. The forwarding adjacency feature allows a tunnel to be installed in the IGP table as a link, making the tunnel part of the IGP topology so that other routers can use it for forwarding traffic. Additionally, the IGP metric of a tunnel can be configured to prefer a certain path, allowing the engineer to influence path selection so that traffic is directed into the tunnel. These two steps ensure that traffic traverses the TE tunnels. This makes options C and D the correct answers.

Why the other options are incorrect:

A. Static routes is the only option for directing traffic into a tunnel – Static routes are not the only option. Autoroute and forwarding adjacency are the primary mechanisms for directing traffic into TE tunnels. Static routes can be used, but they are not the only option.

B. ECMP between tunnels allows RSVP to function correctly – ECMP (Equal-Cost Multi-Path) is a load-balancing mechanism and does not affect RSVP functionality. RSVP operates independently of ECMP.

E. A tunnel weight is configured in SPF database the same way as a native link – While forwarding adjacency allows the tunnel to be treated as a link in the IGP, the concept of a "tunnel weight" configured in the SPF database is not a standard MPLS TE mechanism. The IGP metric of the tunnel is what influences SPF, not a separate tunnel weight.

Reference:
Cisco IOS XR MPLS Configuration Guide – Implementing MPLS Traffic Engineering: Forwarding Adjacency and Autoroute; RFC 4206 – Label Switched Paths (LSP) Hierarchy with Generalized Multi-Protocol Label Switching (GMPLS) Traffic Engineering; Cisco 350-501 SPCOR Official Cert Guide, MPLS Traffic Engineering chapter.

Explanation

In REST APIs, including the Cisco IOS XE REST API, the PUT request method is used to update the specified resource with new information. PUT replaces the entire resource at the target URI with the data provided in the request body. If the resource does not exist, PUT can also create it, but its primary purpose in REST is to update or replace an existing resource. This makes option C the correct answer.

Why the other options are incorrect:

A. Retrieves the specified resource or representation – This describes the GET method, which is used to retrieve data from the server.

B. Submits data to be processed to the specified resource – This describes the POST method, which is used to submit data to be processed, often resulting in the creation of a new resource or triggering an operation.

D. Creates a new resource – While PUT can create a resource if it does not exist, the primary purpose of PUT is to update or replace a resource. The POST method is more commonly associated with creating new resources.

Reference:
RFC 7231 – Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content (PUT method); RFC 8040 – RESTCONF Protocol; Cisco IOS XE REST API Configuration Guide – HTTP Methods; Cisco 350-501 SPCOR Official Cert Guide, Automation and Assurance section.

Explanation

When a router is configured as an OSPF stub router (using the `max-metric router-lsa` command or `stub-router` configuration), it advertises a maximum metric in its router LSA so that other routers do not use it as a transit path. However, the stub router still needs to send traffic outside the OSPF domain. To enable this, a default route must be injected into the OSPF domain so that the stub router has a path to external destinations. The stub router will use the default route to forward traffic toward the ABR or ASBR that originates it. This makes option D the correct answer.

Why the other options are incorrect:

A. Virtual link between RB and RC – A virtual link is used to connect an area to the backbone through a non-backbone area. It is not used to provide a default route for a stub router.

B. Sham link – A sham link is used in MPLS L3VPN to create a virtual link between two Area 0 routers over a VPN backbone. It is not applicable to this plain OSPF stub router scenario.

C. More specific route – Injecting a more specific route does not provide a general path out of the OSPF domain. A default route is the standard mechanism for providing external reachability to a stub router.

Reference:
RFC 2328 – OSPF Version 2; RFC 3137 – OSPF Stub Router Advertisement; Cisco IOS XR Routing Configuration Guide – Implementing OSPF: Stub Router and Default Route Injection; Cisco 350-501 SPCOR Official Cert Guide, OSPF chapter.

Explanation

To force an E-line (point-to-point Ethernet) service to take a specific route over a Cisco MPLS TE tunnel, the service provider uses the preferred path feature. In Cisco IOS XR, the `preferred path` command is used under the L2VPN or pseudowire configuration to direct the pseudowire traffic over a specific MPLS TE tunnel. This allows the E-line service to be mapped to the TE tunnel, ensuring that traffic follows the specific route defined by the tunnel. This makes option B the correct answer.

Why the other options are incorrect:

A. Static route – A static route can direct IP traffic, but it is not the mechanism used to map an E-line (Layer 2) service to an MPLS TE tunnel. The preferred path feature is specifically designed for this purpose.

C. Forwarding adjacency – Forwarding adjacency allows a TE tunnel to be advertised into the IGP as a link, making it part of the IGP topology. It does not directly map an E-line service to a specific tunnel.

D. Autoroute destination – Autoroute destination allows traffic to be routed into a TE tunnel based on the destination prefix. It is used for IP traffic, not for mapping Layer 2 E-line services to a tunnel.

Reference:
Cisco IOS XR MPLS Configuration Guide – Implementing MPLS Traffic Engineering: Preferred Path for L2VPN; Cisco IOS XR L2VPN Configuration Guide – Configuring E-Line Services; Cisco 350-501 SPCOR Official Cert Guide, MPLS Traffic Engineering and L2VPN chapters.

Explanation

To implement IGMP with SSM (Source-Specific Multicast) on a multicampus network supporting video streaming, the engineer must configure the network to use IGMPv3. SSM requires IGMPv3 because it allows receivers to specify both the source address and the multicast group address they want to join, which is the defining characteristic of source-specific multicast. IGMPv1 and IGMPv2 do not support source-specific joins. This makes option A the correct answer.

Why the other options are incorrect:

B. Configure the network to use bidirectional PIM – BIDIR-PIM is used for many-to-many communication with a shared bidirectional tree. It is not used for SSM, which builds source-specific shortest-path trees.

C. Configure an RP that uses static assignments only – SSM does not use a Rendezvous Point (RP) at all. Receivers join the source-specific tree directly using IGMPv3, so no RP configuration is needed.

D. Configure the network to use the PIM bsr-candidate – BSR is used for dynamic RP discovery in PIM-SM. Since SSM does not use an RP, BSR configuration is not required for SSM.

Reference:
RFC 4607 – Source-Specific Multicast for IP; RFC 3376 – Internet Group Management Protocol, Version 3; Cisco IOS XR Multicast Configuration Guide – Configuring PIM-SSM and IGMPv3; Cisco 350-501 SPCOR Official Cert Guide, Multicast chapter.

Explanation

The exhibit shows output that includes a "Control Plane Interface" section with "Service policy CoPP-normal", class-map details, policing rates, and per-slot statistics. This output is from the `show policy-map control-plane` command, which displays the configuration and statistics for the Control Plane Policing (CoPP) policy applied to the control plane. This command allows the engineer to view the policy map, class map matches, policing actions (transmit/drop), and byte/packet counters for each slot, which is exactly what the exhibit shows. This makes option C the correct answer.

Why the other options are incorrect:

A. show control-plane CoPP – This is not a valid Cisco IOS command. The correct command to display CoPP policy statistics is `show policy-map control-plane`.

B. show control-plane – This command displays control plane information but does not specifically show the policy map statistics for CoPP.

D. show policy control-plane – This is not a valid Cisco IOS command. The correct syntax is `show policy-map control-plane`.

Reference:
Cisco IOS XR Security Configuration Guide – Configuring Control Plane Policing (CoPP); Cisco 350-501 SPCOR Official Cert Guide, Security and Network Assurance sections.