1000 Flashcards Cisco Certified Network Professional Exam
EIGRP uses protocol number ______ in the IP header.
EIGRP uses protocol number 88.
What is the difference between a successor and a feasible successor in EIGRP?
A successor is the primary best route to a destination placed in the routing table. A feasible
successor is a loop-free backup route stored in the topology table that satisfies the feasibility
condition.
A router receives an EIGRP route advertisement with a lower reported distance than its feasible
distance. What does this indicate?
This indicates the route satisfies the feasibility condition and may become a feasible successor
because the advertised path is loop-free.
Which command verifies EIGRP neighbors on a Cisco router?
show ip eigrp neighbors verifies adjacency formation, uptime, hold timers, retransmissions, and
sequence numbers.
EIGRP sends periodic full routing table updates every 30 seconds. Explain.
False. EIGRP sends partial and bounded updates only when topology changes occur. Hello
packets are periodic, but routing updates are event-driven.
What are the default hello and hold timers for EIGRP on high-speed links?
Hello timer is 5 seconds and hold timer is 15 seconds on links faster than T1.
Which metric components does EIGRP use by default?
By default, EIGRP uses bandwidth and delay for metric calculation. Reliability and load are
available but disabled unless manually configured.
Explain the feasibility condition in EIGRP.
A neighbor becomes a feasible successor if its reported distance to the destination is lower
than the local router's feasible distance, ensuring loop-free routing.
Which command enables EIGRP on a Cisco router?
router eigrp <ASN> enables the EIGRP routing process for a specified Autonomous System
Number.
A router shows "Active" routes for an extended period. What issue may exist?
This may indicate a Stuck-in-Active (SIA) condition caused by delayed responses, network
congestion, or unreachable neighbors during route recalculation.
1
,1000 Flashcards Cisco Certified Network Professional Exam
What is the function of the EIGRP topology table?
The topology table stores all learned EIGRP routes including successors and feasible
successors before the best route is installed into the routing table.
EIGRP uses multicast address ______ for updates.
EIGRP uses multicast address 224.0.0.10.
Why is unequal-cost load balancing considered an advantage of EIGRP?
EIGRP can distribute traffic across multiple paths with different metrics using the variance
command, improving bandwidth utilization and redundancy.
Which command is used to verify EIGRP routes in the routing table?
show ip route eigrp displays routes learned through EIGRP.
What does the "D" code represent in the Cisco routing table?
"D" represents routes learned through EIGRP.
What is the administrative distance of internal EIGRP routes?
Internal EIGRP routes have an administrative distance of 90.
What is the administrative distance of external EIGRP routes?
External EIGRP routes have an administrative distance of 170.
A network engineer forgets to advertise a subnet in EIGRP. Which command is likely missing?
The network command identifying the subnet under the EIGRP routing process is likely
missing.
Which show command displays all EIGRP topology information?
show ip eigrp topology displays successors, feasible successors, metrics, and route states.
Explain passive-interface usage in EIGRP.
The passive-interface command prevents EIGRP hello packets from being sent on specified
interfaces while still advertising connected networks. It improves security and reduces
unnecessary adjacencies.
EIGRP supports VLSM and CIDR. Explain.
True. EIGRP is a classless routing protocol that supports subnet masks in routing updates,
allowing VLSM and CIDR implementation.
2
,1000 Flashcards Cisco Certified Network Professional Exam
Which EIGRP packet type is used to discover neighbors?
Hello packets are used for neighbor discovery and adjacency maintenance.
What does RTP stand for in EIGRP?
RTP stands for Reliable Transport Protocol, which guarantees ordered and reliable delivery of
EIGRP packets.
What is route summarization in EIGRP?
Route summarization combines multiple networks into a single advertisement to reduce routing
table size and improve scalability.
Which command manually configures EIGRP route summarization?
ip summary-address eigrp <ASN> <summary-address> <mask>
A router cannot form EIGRP adjacency with a neighbor. Name two common causes.
Mismatched Autonomous System numbers and mismatched K-values are common causes.
The EIGRP finite-state machine algorithm is called ______.
The algorithm is called DUAL.
Why are K-values important in EIGRP?
K-values determine which metric components are used in route calculations. All neighboring
routers must use identical K-values to form adjacencies.
Which command displays EIGRP protocol parameters including K-values?
show ip protocols
What is stub routing in EIGRP?
Stub routing limits query propagation by defining routers that should not be used as transit
paths, reducing network overhead.
Which command configures an EIGRP stub router?
eigrp stub under the EIGRP routing process.
EIGRP is considered a pure link-state protocol. Explain.
False. EIGRP is often called a hybrid routing protocol because it combines features of both
distance-vector and link-state protocols.
3
, 1000 Flashcards Cisco Certified Network Professional Exam
What does the variance command accomplish in EIGRP?
The variance command enables unequal-cost load balancing by including routes whose
metrics are within the specified multiplier.
Which metric value is preferred in EIGRP routing decisions?
The route with the lowest feasible distance metric is preferred.
A router receives no EIGRP updates despite proper IP connectivity. Which security feature
could block adjacency?
Authentication mismatches using MD5 or HMAC authentication can prevent adjacency
formation.
Which command enables MD5 authentication on EIGRP interfaces?
ip authentication mode eigrp <ASN> md5
Why is EIGRP considered bandwidth efficient?
EIGRP sends incremental updates only when changes occur instead of transmitting full routing
tables periodically.
Define OSPF.
Open Shortest Path First (OSPF) is a link-state routing protocol that uses the SPF algorithm to
calculate shortest paths and supports hierarchical network design.
Which algorithm does OSPF use to calculate shortest paths?
OSPF uses the Dijkstra Shortest Path First (SPF) algorithm.
OSPF uses multicast address ______ for all SPF routers.
OSPF uses multicast address 224.0.0.5.
What is the backbone area in OSPF?
Area 0 is the backbone area responsible for inter-area communication and central connectivity
in multi-area OSPF designs.
What is the purpose of dividing OSPF into multiple areas?
Multi-area OSPF reduces SPF recalculations, minimizes LSDB size, lowers CPU utilization,
and improves scalability.
Which OSPF router type connects multiple areas?
An Area Border Router (ABR) connects multiple OSPF areas.
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EIGRP uses protocol number ______ in the IP header.
EIGRP uses protocol number 88.
What is the difference between a successor and a feasible successor in EIGRP?
A successor is the primary best route to a destination placed in the routing table. A feasible
successor is a loop-free backup route stored in the topology table that satisfies the feasibility
condition.
A router receives an EIGRP route advertisement with a lower reported distance than its feasible
distance. What does this indicate?
This indicates the route satisfies the feasibility condition and may become a feasible successor
because the advertised path is loop-free.
Which command verifies EIGRP neighbors on a Cisco router?
show ip eigrp neighbors verifies adjacency formation, uptime, hold timers, retransmissions, and
sequence numbers.
EIGRP sends periodic full routing table updates every 30 seconds. Explain.
False. EIGRP sends partial and bounded updates only when topology changes occur. Hello
packets are periodic, but routing updates are event-driven.
What are the default hello and hold timers for EIGRP on high-speed links?
Hello timer is 5 seconds and hold timer is 15 seconds on links faster than T1.
Which metric components does EIGRP use by default?
By default, EIGRP uses bandwidth and delay for metric calculation. Reliability and load are
available but disabled unless manually configured.
Explain the feasibility condition in EIGRP.
A neighbor becomes a feasible successor if its reported distance to the destination is lower
than the local router's feasible distance, ensuring loop-free routing.
Which command enables EIGRP on a Cisco router?
router eigrp <ASN> enables the EIGRP routing process for a specified Autonomous System
Number.
A router shows "Active" routes for an extended period. What issue may exist?
This may indicate a Stuck-in-Active (SIA) condition caused by delayed responses, network
congestion, or unreachable neighbors during route recalculation.
1
,1000 Flashcards Cisco Certified Network Professional Exam
What is the function of the EIGRP topology table?
The topology table stores all learned EIGRP routes including successors and feasible
successors before the best route is installed into the routing table.
EIGRP uses multicast address ______ for updates.
EIGRP uses multicast address 224.0.0.10.
Why is unequal-cost load balancing considered an advantage of EIGRP?
EIGRP can distribute traffic across multiple paths with different metrics using the variance
command, improving bandwidth utilization and redundancy.
Which command is used to verify EIGRP routes in the routing table?
show ip route eigrp displays routes learned through EIGRP.
What does the "D" code represent in the Cisco routing table?
"D" represents routes learned through EIGRP.
What is the administrative distance of internal EIGRP routes?
Internal EIGRP routes have an administrative distance of 90.
What is the administrative distance of external EIGRP routes?
External EIGRP routes have an administrative distance of 170.
A network engineer forgets to advertise a subnet in EIGRP. Which command is likely missing?
The network command identifying the subnet under the EIGRP routing process is likely
missing.
Which show command displays all EIGRP topology information?
show ip eigrp topology displays successors, feasible successors, metrics, and route states.
Explain passive-interface usage in EIGRP.
The passive-interface command prevents EIGRP hello packets from being sent on specified
interfaces while still advertising connected networks. It improves security and reduces
unnecessary adjacencies.
EIGRP supports VLSM and CIDR. Explain.
True. EIGRP is a classless routing protocol that supports subnet masks in routing updates,
allowing VLSM and CIDR implementation.
2
,1000 Flashcards Cisco Certified Network Professional Exam
Which EIGRP packet type is used to discover neighbors?
Hello packets are used for neighbor discovery and adjacency maintenance.
What does RTP stand for in EIGRP?
RTP stands for Reliable Transport Protocol, which guarantees ordered and reliable delivery of
EIGRP packets.
What is route summarization in EIGRP?
Route summarization combines multiple networks into a single advertisement to reduce routing
table size and improve scalability.
Which command manually configures EIGRP route summarization?
ip summary-address eigrp <ASN> <summary-address> <mask>
A router cannot form EIGRP adjacency with a neighbor. Name two common causes.
Mismatched Autonomous System numbers and mismatched K-values are common causes.
The EIGRP finite-state machine algorithm is called ______.
The algorithm is called DUAL.
Why are K-values important in EIGRP?
K-values determine which metric components are used in route calculations. All neighboring
routers must use identical K-values to form adjacencies.
Which command displays EIGRP protocol parameters including K-values?
show ip protocols
What is stub routing in EIGRP?
Stub routing limits query propagation by defining routers that should not be used as transit
paths, reducing network overhead.
Which command configures an EIGRP stub router?
eigrp stub under the EIGRP routing process.
EIGRP is considered a pure link-state protocol. Explain.
False. EIGRP is often called a hybrid routing protocol because it combines features of both
distance-vector and link-state protocols.
3
, 1000 Flashcards Cisco Certified Network Professional Exam
What does the variance command accomplish in EIGRP?
The variance command enables unequal-cost load balancing by including routes whose
metrics are within the specified multiplier.
Which metric value is preferred in EIGRP routing decisions?
The route with the lowest feasible distance metric is preferred.
A router receives no EIGRP updates despite proper IP connectivity. Which security feature
could block adjacency?
Authentication mismatches using MD5 or HMAC authentication can prevent adjacency
formation.
Which command enables MD5 authentication on EIGRP interfaces?
ip authentication mode eigrp <ASN> md5
Why is EIGRP considered bandwidth efficient?
EIGRP sends incremental updates only when changes occur instead of transmitting full routing
tables periodically.
Define OSPF.
Open Shortest Path First (OSPF) is a link-state routing protocol that uses the SPF algorithm to
calculate shortest paths and supports hierarchical network design.
Which algorithm does OSPF use to calculate shortest paths?
OSPF uses the Dijkstra Shortest Path First (SPF) algorithm.
OSPF uses multicast address ______ for all SPF routers.
OSPF uses multicast address 224.0.0.5.
What is the backbone area in OSPF?
Area 0 is the backbone area responsible for inter-area communication and central connectivity
in multi-area OSPF designs.
What is the purpose of dividing OSPF into multiple areas?
Multi-area OSPF reduces SPF recalculations, minimizes LSDB size, lowers CPU utilization,
and improves scalability.
Which OSPF router type connects multiple areas?
An Area Border Router (ABR) connects multiple OSPF areas.
4
