Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
What is the effect of route summarization at an area boundary or redistribution point?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
It increases the administrative distance of all routes.
Summarization does not change AD by itself.
B
Best answer
It combines multiple more-specific routes into a shorter prefix advertisement.
Correct. That is the purpose of summarization.
C
Distractor review
It forces equal-cost load balancing across all paths.
Summarization and ECMP are unrelated concepts.
D
Distractor review
It prevents the use of a default route.
Summarization does not prevent default routing.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is assuming that route summarization changes the administrative distance or forces load balancing. Some candidates incorrectly believe summarization modifies route preference or influences path selection metrics. However, summarization only aggregates multiple specific routes into a single, broader prefix advertisement without altering administrative distance or load balancing behavior. Misunderstanding this can lead to wrong answers, especially when options mention administrative distance changes or load balancing effects, which are unrelated to summarization.
Technical deep dive
How to think about this question
Route summarization is a routing optimization technique used to reduce the size of routing tables by combining multiple contiguous network prefixes into a single, summarized route advertisement. This process is especially important in large networks to improve routing efficiency and reduce overhead. Summarization occurs at area boundaries in OSPF or at redistribution points between different routing protocols, where multiple specific routes can be represented as a single, less-specific prefix. When a router performs route summarization at an area boundary or redistribution point, it advertises a shorter prefix that encompasses multiple more-specific routes. This reduces the number of routes that downstream routers must process and store, improving convergence times and reducing CPU and memory usage. Cisco routers support manual and automatic summarization depending on the routing protocol, but the key effect is always the aggregation of routes into a summarized advertisement. A common exam trap is confusing route summarization with changes to administrative distance or load balancing. Summarization does not alter the administrative distance of routes nor does it enforce equal-cost load balancing. Instead, it simply reduces routing table size by advertising fewer, aggregated routes. Practically, summarization helps contain routing updates within an area or protocol domain, preventing unnecessary propagation of detailed routing information and improving network scalability.
KKey Concepts to Remember
- Route summarization combines multiple contiguous, more-specific routes into a single, less-specific prefix to reduce routing table size and update overhead.
- Routers perform summarization at area boundaries in OSPF or at redistribution points between routing protocols to optimize routing efficiency.
- Summarization does not change the administrative distance or metric of routes; it only aggregates route advertisements.
- A summarized route advertisement reduces the number of routing entries that downstream routers must process and store.
- Route summarization helps contain routing updates within a routing domain, improving network scalability and convergence times.
- Cisco routers support manual summarization commands to control how routes are aggregated at redistribution or area boundaries.
- Summarization does not force equal-cost load balancing or prevent the use of default routes in routing protocols.
- Understanding the difference between summarization effects and administrative distance or load balancing is critical for CCNA exam success.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Route summarization combines multiple contiguous, more-specific routes into a single, less-specific prefix to reduce routing table size and update overhead.
What is the correct answer to this question?
The correct answer is: It combines multiple more-specific routes into a shorter prefix advertisement. — Summarization reduces the number of routes advertised by combining contiguous networks into a shorter prefix.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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