Cisco CCNA Static and Dynamic Routing 5 — Questions and Answers
Question 1: Which routing protocol uses Dijkstra's Shortest Path First (SPF) algorithm to calculate the best path?
- EIGRP
- RIPv2
- OSPF (Correct answer)
- BGP
Correct answer: OSPF
OSPF uses Dijkstra's SPF algorithm to compute the shortest path tree from the LSDB, determining the best loop-free path to each destination.
Question 2: A network administrator configures 'ip route 10.10.10.0 255.255.255.0 Null0'. What is the most common reason for this type of configuration?
- To create a backup route if the primary path fails
- To act as a summary route discard route, preventing routing loops for summarized addresses with no more-specific match (Correct answer)
- To block all traffic destined for 10.10.10.0/24
- To advertise 10.10.10.0/24 into BGP
Correct answer: To act as a summary route discard route, preventing routing loops for summarized addresses with no more-specific match
A Null0 static route is used as a discard route paired with a route summary, dropping packets for summarized addresses that have no specific destination.
Question 3: Which EIGRP packet type is used to acknowledge EIGRP updates and ensure reliable delivery?
- Hello
- Query
- Reply
- Acknowledgment (Correct answer)
Correct answer: Acknowledgment
EIGRP uses explicit Acknowledgment packets to confirm receipt of reliable packets like Updates, Queries, and Replies.
Question 4: In OSPF, what triggers a router to transition from the 'Loading' state to the 'Full' state?
- The dead timer expires without receiving a Hello
- The router receives all requested LSAs and its LSDB is synchronized with the neighbor (Correct answer)
- The DR election completes successfully
- The router's SPF calculation finishes
Correct answer: The router receives all requested LSAs and its LSDB is synchronized with the neighbor
A router moves to the Full state once it has successfully received all LSAs requested during the Loading state, completing database synchronization.
Question 5: Which statement about RIPv1 versus RIPv2 is accurate?
- RIPv1 supports VLSM and CIDR while RIPv2 does not
- RIPv2 sends updates as multicast to 224.0.0.9 and includes subnet mask information, unlike RIPv1 (Correct answer)
- Both versions use the same maximum hop count of 15 and identical update intervals
- RIPv2 uses Dijkstra's algorithm while RIPv1 uses Bellman-Ford
Correct answer: RIPv2 sends updates as multicast to 224.0.0.9 and includes subnet mask information, unlike RIPv1
RIPv2 improves on RIPv1 by using multicast (224.0.0.9) for updates and including subnet mask information, enabling support for VLSM and CIDR.
Question 6: A router receives packets for destination 192.168.100.50. The routing table has entries for 192.168.100.0/24, 192.168.0.0/16, and 0.0.0.0/0. Which route is selected?
- 0.0.0.0/0 because it matches all destinations
- 192.168.0.0/16 because it is the second most specific match
- 192.168.100.0/24 because longest prefix match is used (Correct answer)
- The router load-balances across all three matching routes
Correct answer: 192.168.100.0/24 because longest prefix match is used
Cisco routers use longest prefix match, so 192.168.100.0/24 with a /24 prefix is more specific than /16 or /0 and is selected.
Question 7: Which command enables EIGRP on all interfaces with addresses in the 10.0.0.0 class A range for EIGRP AS 100?
- router eigrp 100 / network 10.0.0.0 0.255.255.255
- router eigrp 100 / network 10.0.0.0 (Correct answer)
- eigrp 100 / enable network 10.0.0.0/8
- router eigrp 100 / network 10.0.0.0 255.0.0.0
Correct answer: router eigrp 100 / network 10.0.0.0
In EIGRP, 'network 10.0.0.0' without a wildcard mask uses the classful boundary (/8 for Class A), enabling EIGRP on all interfaces in that range.
Cisco CCNA Static and Dynamic Routing 5
Which routing protocol uses Dijkstra's Shortest Path First (SPF) algorithm to calculate the best path?