Free SPCOR Practice Questions

Question 1

Two valid multihop eBGP paths compete for 203.0.113.0/24 on an IOS XE border router. Both have weight 0, local preference 150, and origin IGP; neither is locally originated. AIGP and cost communities are absent, and bgp always-compare-med is not configured.

West: AS_PATH 64520 64496; MED 5; next-hop IGP cost 50; neighbor router ID 192.0.2.20; learned two hours ago.
East: AS_PATH 64521 64496; MED 80; next-hop IGP cost 10; neighbor router ID 192.0.2.10; learned ten minutes ago.

Which selection should appear in the BGP table?

Accepted Answer

East: MED is skipped between these neighboring ASes, and its next-hop IGP cost is lower.

Answer

West: MED is compared because both AS paths end in AS 64496, and its value is lower.

Answer

West: its older external path is preferred before the next-hop IGP costs are compared.

Answer

East: its lower neighbor router ID decides before the next-hop IGP costs are compared.

Question 2

VRF BLUE must receive a newly approved shared-service prefix. On the receiving PE, the VPNv4 route is valid, its labeled next hop is reachable, and it carries RD 65000:900 and RT 65000:500. BLUE uses RD 65000:101 and imports and exports only RT 65000:101. RT 65000:500 is reserved for the approved shared-service routes. The prefix is missing from BLUE. Select the change that admits this route without changing BLUE's export policy.

Accepted Answer

Add RT 65000:500 to BLUE's import route-target set.

Answer

Replace BLUE's RD 65000:101 with the shared service's RD 65000:900.

Answer

Add RT 65000:500 to BLUE's export route-target set.

Answer

Enable VPNv4 on the PE peer and retain BLUE's existing route targets.

Question 3

During a transit-router replacement, the OSPF adjacency reaches FULL before LDP has exchanged the necessary label bindings. Traffic moves from a working alternate MPLS path onto the restored lower-cost link, and several L3VPNs briefly lose connectivity. Which feature would prevent the restored link from attracting this traffic before label forwarding is ready?

Accepted Answer

LDP IGP synchronization

Answer

LDP session protection

Answer

BFD with a shorter detection interval

Answer

Explicit-null advertisement for PE loopbacks

Question 4

Monitoring flags R1 and R2 because their OSPFv2 relationship has stayed in 2-Way for an hour. They share a broadcast Ethernet segment with two other routers. R1 and R2 are both DROTHER, each is FULL with the DR and BDR, and the expected routes are installed. A colleague proposes restarting OSPF on R1 and R2 to force full adjacency. How should this alert be handled?

Accepted Answer

Classify the DROTHER-to-DROTHER state as expected; leave OSPF running.

Answer

Restart both processes so the neighbors repeat database synchronization from ExStart.

Answer

Apply MTU-ignore on both interfaces so database-description packets can be accepted.

Answer

Change the segment to OSPF point-to-multipoint mode so every neighbor can synchronize directly.

Question 5

During a code review, an engineer finds this RESTCONF write to an IOS XE router. The server exposes ietf-system and supports plain PATCH. The authenticated HTTPS session s has permission to update the existing system resource.

s.put(
    'https://pe1.example/restconf/data/ietf-system:system',
    headers={'Content-Type': 'application/yang-data+json'},
    json={'ietf-system:system': {'contact': 'noc-west'}}
)

The intended change is only the contact; the configured hostname and other system values must survive. What correction should the reviewer request?

Accepted Answer

Use s.patch with the same URI, media type, and payload.

Answer

Keep s.put and add an If-Match header containing the system resource's current entity tag.

Answer

Keep s.put and add an Accept header requesting an application/yang-data+json response.

Answer

Use s.post with the same URI, media type, and payload.

Question 6

A UDP reflection attack saturates an emergency dispatch center's provider-to-customer access link. The targeted IPv4 gateway also terminates essential HTTPS sessions and IPsec NAT traversal on UDP 4500; both services are failing. Captures confirm that the entire flood consists of unfragmented UDP packets with source port 123, and no legitimate traffic to this address uses that source port. An authorized FlowSpec controller can install filters at every attack ingress before the saturated link. Which immediate action restores capacity while preserving both legitimate services?

Accepted Answer

Install an upstream FlowSpec discard rule matching destination gateway /32, UDP, and source port 123.

Answer

Advertise a destination RTBH route for the gateway's /32 to all provider edges.

Answer

Install an upstream FlowSpec discard rule for all UDP destined to the gateway's /32.

Answer

Apply an inbound ACL on the customer router matching destination gateway /32, UDP, and source port 123.

Question 7

An otherwise eligible BGP route arrives at an IOS XR router with MED 80. The inbound policy is:

route-policy TRANSIT-IN
  if med ge 70 then
    set med 30
  endif
  if med le 50 then
    drop
  else
    pass
  endif
end-policy

Which statement correctly describes the result and the policy's execution?

Accepted Answer

It accepts the route with MED 30; the second test evaluates the received MED 80.

Answer

It drops the route after setting MED 30; the second test evaluates the modified MED.

Answer

It accepts the route with MED 30; setting an attribute immediately ends policy evaluation.

Answer

It drops the route at end-policy; an explicit done action is required for acceptance.

Question 8

R1 receives a VPN packet with MPLS label stack [16077, 90000], outermost first. Label 16077 is the transport label for a remote PE's Prefix-SID index 77; label 90000 identifies the VPN at that PE. R1's single SRGB is 16000-23999; next hop R2's is 24000-31999. R1 continues the same segment through R2 without popping a label. What label stack leaves R1?

Accepted Answer

[24077, 90000]

Answer

[16077, 90000]

Answer

[24077, 24077]

Answer

[90000, 24077]

Question 9

An IPTV source has moved to a new uplink. Receivers still send IGMPv3 INCLUDE reports for source 192.0.2.44 and group 232.10.10.10, and the receiver-facing interface is in the multicast outgoing list. Source traffic arrives on the intended Gi0/1 uplink, but multicast input drops rise. The router uses its unicast table for RPF lookup; the selected route to 192.0.2.44 still points through Gi0/0. Which fault best fits these observations?

Accepted Answer

The source route selects the wrong incoming interface for the RPF check.

Answer

The group lacks an RP mapping, preventing the router from building the source-specific tree.

Answer

IGMPv3 INCLUDE suppresses this channel until the receiver switches to an EXCLUDE report.

Answer

Gi0/1 is missing from the outgoing interface list, preventing arriving packets from being replicated.

Question 10

An operator is commissioning Ethernet fronthaul between O-RAN radio units and distributed units. After local satellite timing receivers are removed, the radios remain frequency-locked through SyncE. A radio-frame alignment test measures an 8-microsecond offset from the common time reference; this deployment requires alignment within ±1.5 microseconds. Packet loss and delay meet acceptance limits. A central timing grandmaster and compatible timing-capable transport equipment are available. Which addition supplies the missing synchronization function?

Accepted Answer

Deliver PTP time and phase from the grandmaster.

Answer

Increase the selection priority of the existing SyncE frequency reference.

Answer

Reserve more output-queue bandwidth for the existing fronthaul traffic.

Answer

Extend Ethernet Synchronization Messaging Channel quality advertisements to the radio units.

Free SPCOR Practice Questions

Domain 1: Architecture 15% of exam

Question 1

Question 2

Domain 2: Networking 30% of exam

Question 3

Question 4

Question 5

Domain 3: MPLS and Segment Routing 20% of exam

Question 6

Question 7

Domain 4: Services 20% of exam

Question 8

Question 9

Domain 5: Automation and Assurance 15% of exam

Question 10

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