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

Explanation

The exhibit shows `channel-group 1 mode desirable` on the interface. In Cisco IOS, the `desirable` mode is a PAgP (Port Aggregation Protocol) mode that actively sends PAgP packets to negotiate an EtherChannel with the connected peer. The `desirable` mode is not passive; it actively initiates the negotiation. This makes option A the correct answer.

Why the other options are incorrect:

B. The switch port accepts LACP and PAgP packets from a connected peer and negotiates an EtherChannel using the common EtherChannel mode
The `desirable` mode is specific to PAgP and does not accept LACP packets. LACP uses `active` or `passive` modes, not `desirable`.

C. The switch port passively negotiates an EtherChannel if it receives PAgP packets from a connected peer
Passive negotiation using PAgP is the `auto` mode, not `desirable`. The `desirable` mode actively initiates negotiation.

D. The switch port negotiates an EtherChannel if it receives LACP packets from a connected peer
The `desirable` mode uses PAgP, not LACP. LACP negotiation would require `active` or `passive` mode.

Reference:
Cisco IOS XR Interface and Hardware Component Configuration Guide – Configuring Link Bundling: PAgP and LACP Modes; IEEE 802.3ad – Link Aggregation; Cisco 350-501 SPCOR Official Cert Guide, Network Assurance section.

Explanation

When creating a new Cisco MPLS TE tunnel, the headend router sends an RSVP Path message toward the tunnel's tailend (egress) router. The Path message carries the traffic engineering parameters, including the required bandwidth (Tspec), the explicit route object (ERO) if an explicit path is used, and the session information. Each intermediate router along the path processes the Path message and forwards it toward the destination. The tailend router then responds with an RSVP Reservation (Resv) message that travels back toward the headend, reserving the requested bandwidth on each hop. Since the question asks which message the headend sends to reserve bandwidth on the path, the correct answer is the Path message — it is the first message sent by the headend that initiates the bandwidth reservation process. This makes option C the correct answer.

Why the other options are incorrect:

A. Error
An RSVP Error message is sent when a node cannot satisfy the reservation request, such as when bandwidth is insufficient. It is not used to initiate a reservation.

B. Reservation
The Reservation (Resv) message is sent by the tailend router back toward the headend to confirm the reservation. It is not sent by the headend to initiate the process.

D. Tear
A Tear message is used to tear down an existing reservation or path. It is not used to create a new reservation.

Reference:
RFC 3209 – RSVP-TE: Extensions to RSVP for LSP Tunnels; Cisco IOS XR MPLS Configuration Guide – Implementing MPLS Traffic Engineering: RSVP Signaling; Cisco 350-501 SPCOR Official Cert Guide, MPLS Traffic Engineering chapter.

Explanation

The exhibit shows interface G0/1 configured with `ip ospf 1 area 0` and `ip ospf multi-area 10`. The `ip ospf multi-area` command is used in OSPF multiarea configurations to allow an interface to participate in multiple areas, typically for multiarea adjacencies. When an interface is configured with multi-area, it is commonly used on point-to-point links to form adjacencies in multiple areas. However, by default, an Ethernet interface operates as a broadcast network type, which can cause adjacency issues in a multiarea configuration because broadcast networks require DR/BDR election and are not suitable for multiarea adjacencies. Changing the interface to `ip ospf network point-to-point` eliminates the DR/BDR election and allows the multiarea adjacency to form correctly. This makes option B the correct answer.

Why the other options are incorrect:

A. `ip ospf network broadcast`
Broadcast is the default network type on Ethernet interfaces, so this command would not change anything and would not resolve the adjacency issues in the multiarea configuration.

C. `ip ospf network non-broadcast`
The non-broadcast network type requires manual neighbor configuration and is used for NBMA networks such as Frame Relay. It is not the appropriate choice for resolving multiarea adjacency issues on an Ethernet link.

D. `ip ospf network point-to-multipoint`
Point-to-multipoint is used for hub-and-spoke topologies and does not require DR/BDR election, but it is not the standard choice for a point-to-point multiarea adjacency. Point-to-point is the more appropriate and commonly used network type for this scenario.

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

Explanation

The output shows targeted hello adjacencies, which appear as entries starting with `Tgt:`. The `Tgt:192.168.0.5` entry shows a dash (`-`) in the Peer LDP Id column and `N` in the Holdtime column, indicating that the targeted hello adjacency exists but the LDP session is not currently active. The other targeted entries (`Tgt:192.168.0.1` and `Tgt:192.168.0.3`) show peer LDP IDs and `Y` in the Holdtime column, meaning their sessions are active. Therefore, the router with which IOSXRV-1 has LDP session protection capability enabled but no active session is **192.168.0.5**. This makes option D the correct answer.

Why the other options are incorrect:

A. 192.168.0.1
The `Tgt:192.168.0.1` entry shows Peer LDP Id `192.168.0.1:0` and Holdtime `90` with `Y`, indicating an active session.

B. 192.168.0.3
The `Tgt:192.168.0.3` entry shows Peer LDP Id `192.168.0.3:0` and Holdtime `90` with `Y`, indicating an active session.

C. 192.168.0.4
The `Gi0/0/2` entry shows `192.168.0.4:0` with Holdtime `15` and `Y`, indicating an active link-level LDP session, not a session protection scenario.

Reference:
RFC 5036 – LDP Specification; Cisco IOS XR MPLS Configuration Guide – Implementing LDP: Session Protection and Targeted Hellos; Cisco 350-501 SPCOR Official Cert Guide, MPLS chapter.

Explanation

To meet the requirements, the customer in Area 2 (IS-IS Level 1) needs access to the `10.10.10.0/24` subnet in Area 1, but must not have access to the `20.10.30.0/24` subnet. Additionally, the routing database in Area 2 must be limited in the number of IP addresses. The solution is to summarize the Area 1 prefixes into a single summary route (`10.0.0.0/16`) on R2, which is the Level 1/Level 2 router connecting Area 1 to the Level 2 backbone, and tag that summary with a value of 200. Then, on R3 (the Level 1/Level 2 router connecting the Level 2 backbone to Area 2), a route map matching tag 200 is applied to leak the tagged Level 2 routes into Level 1 Area 2. This allows only the summarized prefix (which includes `10.10.10.0/24` but not `20.10.30.0/24`) into Area 2, limiting the routing table size and controlling access. This makes options A and C the correct answers.

Why the other options are incorrect:

B. Set a tag value of 200 to match the summary address `10.0.0.0/16` on R3
R3 is the router connecting to Area 2, but the summarization should occur on R2, which is the router connecting Area 1 to the Level 2 backbone. Tagging on R3 would not summarize the Area 1 prefixes before they enter the Level 2 domain.

D. Apply the route map for tag 200 and leak Level 2 routes into Level 1 Area 2 on R4
R4 is entirely within Area 2 (IS-IS L1 Area 2) and is not a Level 1/Level 2 router. Route leaking from Level 2 into Level 1 must be done on the Level 1/Level 2 router, which is R3, not R4.

E. Set a tag value of 200 to match the summary address `10.0.0.0/16` on R1
R1 is within Area 1 and is a Level 1 router. Summarization and tagging for leaking into Area 2 should be done on the Level 1/Level 2 router (R2) that connects Area 1 to the backbone, not on R1.

Reference:
ISO/IEC 10589 – IS-IS for Routing Information Exchange; RFC 5305 – IS-IS Extensions for Traffic Engineering; Cisco IOS XR Routing Configuration Guide – Implementing IS-IS: Route Leaking and Summarization; Cisco 350-501 SPCOR Official Cert Guide, IS-IS chapter.

Explanation

The requirement is to advertise only `10.16.4.0/24`, `10.16.5.0/24`, and the summarized route `10.16.0.0/21`, while suppressing the more specific `10.16.6.0/24`. The access list `Suppressed` permits `10.16.6.0/24`, and the route map `SuppressMap` matches that access list to identify the prefix to be suppressed. The `aggregate-address` command with `as-set` and `suppress-map` is used to create the summary route and suppress the specified more-specific routes. The correct summary route is `10.16.0.0/21`, which covers `10.16.0.0` through `10.16.7.255`, and the suppress map references the `SuppressMap` route map. Option B uses `aggregate-address 10.16.0.0 255.255.248.0 as-set suppress-map SuppressMap`, which correctly summarizes to /21 and applies the suppress map. This makes option B the correct answer.

Why the other options are incorrect:

A. Option A
It uses a mask of `255.255.252.0`, which is a /22 summary (`10.16.0.0/22`), not the required /21. This would not cover `10.16.4.0/24` and `10.16.5.0/24` within the summary route.

C. Option C
It uses `aggregate-address 10.16.6.0 255.255.255.0`, which summarizes the `10.16.6.0/24` prefix itself instead of creating the required `10.16.0.0/21` summary route.

D. Option D
It uses `aggregate-address 10.16.0.0 255.255.255.0` (a /24 summary), which is incorrect for summarizing `10.16.0.0/21`, and it uses `unSuppressMap` instead of `suppress-map`, which is not valid for suppressing specific prefixes.

Reference:
Cisco IOS XR Routing Configuration Guide – Implementing BGP: Aggregate Address and Suppress Map; RFC 4271 – A Border Gateway Protocol 4 (BGP-4); Cisco 350-501 SPCOR Official Cert Guide, BGP chapter.

Explanation

A Prefix Segment Identifier (Prefix-SID) in Segment Routing identifies a prefix, typically a loopback address, and is globally unique within the Segment Routing domain. The Prefix-SID is advertised by the IGP (OSPF or IS-IS) and represents the shortest path to the node's prefix. Because it must be understood by all routers in the SR domain to forward traffic correctly to that prefix, it must be unique across the entire domain, not just locally on a single router. This makes option C the correct answer.

Why the other options are incorrect:

A. It contains a router to a neighbor
A Prefix-SID identifies a prefix (node), not a neighbor relationship. Adjacency SIDs are used to identify a specific neighbor or link.

B. It contains the interface address of the device per each link
A Prefix-SID is associated with a prefix (usually a loopback), not with each individual interface address on every link. Interface addresses are not the basis of Prefix-SIDs.

D. It is locally unique
Locally unique identifiers are Adjacency SIDs, which are significant only on the router that advertises them. Prefix-SIDs must be globally unique within the SR domain.

Reference:
RFC 8402 – Segment Routing Architecture; RFC 8665 – OSPF Extensions for Segment Routing; Cisco IOS XR Segment Routing Configuration Guide – Configuring Prefix-SIDs; Cisco 350-501 SPCOR Official Cert Guide, Segment Routing chapter.

Explanation

The exhibit shows that Router BRDR-1 is configured to redistribute BGP into OSPF with a route policy, and the BGP route table shows the `0.0.0.0/0` default route learned via BGP. However, the default route is not appearing in OSPF Area 0. The issue is that the `redistribute bgp 65001 route-policy BGP-TO-OSPF` command redistributes BGP routes into OSPF as external Type 2 (or Type 1) LSAs, but a default route (`0.0.0.0/0`) is not automatically injected into OSPF just by redistribution unless `default-information originate` is configured. To inject the default route into OSPF, the `default-information originate` command must be used under the OSPF process. Option A uses `default-information originate always`, which injects the default route into OSPF unconditionally, ensuring the `0.0.0.0/0` route is advertised into Area 0. This makes option A the correct answer.

Why the other options are incorrect:

B. Option B
It uses `redistribute bgp 65001 metric 100 route-policy BGP-TO-OSPF`, which redistributes BGP routes with a metric but still does not inject the default route unless the default route is explicitly matched and redistributed. The default route would not be automatically included without `default-information originate`.

C. Option C
It sets `default-metric 100` under OSPF, which changes the metric used for redistributed routes but does not inject a default route into OSPF.

D. Option D
It uses `default-information originate` without the `always` keyword, which only injects the default route if the router already has a default route in its routing table. While this could work in some cases, the `always` keyword in Option A ensures the default route is always advertised regardless of whether a default route exists in the RIB, which is the more reliable solution for this scenario. Option A is the preferred configuration.

Reference:
Cisco IOS XR Routing Configuration Guide – Implementing OSPF: Default Information Originate; RFC 2328 – OSPF Version 2; Cisco 350-501 SPCOR Official Cert Guide, OSPF and BGP chapters.

Explanation

The requirement is to configure Flexible NetFlow with IPFIX export. The destination server is `172.17.12.1`, the source must be `Loopback0`, the DSCP must be CS3, the TTL must be `64`, and the transport protocol must be UDP with destination port `4739`. DSCP CS3 corresponds to a decimal value of 24 (CS3 = `011000` binary = 24 decimal). The export protocol must be IPFIX (not NetFlow v9), and the transport must be UDP with port `4739`, which is the standard IPFIX port. Option A correctly configures `destination 172.17.12.1`, `source Loopback0`, `dscp 24` (which is CS3), `ttl 64`, and `export-protocol ipfix`. This makes option A the correct answer.

Why the other options are incorrect:

B. Option B
It uses `dscp 3` instead of `dscp 24`. DSCP 3 is not CS3; CS3 is decimal 24. This is the wrong DSCP value.

C. Option C
It uses `export-protocol netflow-v9` instead of `ipfix`. The requirement specifically states IPFIX export, and the transport port `4739` is the IPFIX port, not the commonly used NetFlow v9 port (`2055`).

D. Option D
It uses both `dscp 3` (incorrect; it should be 24) and `export-protocol netflow-v9` (incorrect; it should be `ipfix`). Both parameters are wrong.

Reference:
RFC 7011 – Specification of the IP Flow Information Export (IPFIX) Protocol; Cisco IOS XR NetFlow Configuration Guide – Configuring Flexible NetFlow and IPFIX Export; Cisco 350-501 SPCOR Official Cert Guide, Network Assurance section.