Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
What is the main operational benefit of summarizing multiple routes into one broader prefix where appropriate?
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
Best answer
It reduces the number of specific routes that must be carried or advertised.
This is correct because summarization aggregates routes into fewer entries.
B
Distractor review
It guarantees every packet uses only the default route.
This is wrong because summarization does not replace all routing with a default route.
C
Distractor review
It automatically encrypts route updates.
This is wrong because summarization and encryption are unrelated functions.
D
Distractor review
It removes the need for subnet masks.
This is wrong because summarization does not eliminate addressing structure.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is assuming that route summarization causes all traffic to use a default route or that it encrypts routing updates. Summarization only aggregates multiple specific routes into one broader prefix; it does not replace routing with a default route nor provide any security features. Misunderstanding this can lead to selecting incorrect answers that confuse summarization with default routing or encryption, which are separate networking functions.
Technical deep dive
How to think about this question
Route summarization is a technique used in IP routing to combine multiple contiguous network prefixes into a single, broader prefix. This reduces the number of routes that routers must store and advertise, which simplifies the routing table and improves overall network efficiency. Summarization is particularly important in hierarchical network designs where multiple subnets can be aggregated into one summary route to reduce routing overhead. In Cisco routing protocols such as OSPF and EIGRP, summarization is applied at specific points like area borders or autonomous system boundaries. The router calculates the summary address by identifying the common bits among the routes to be summarized and advertises this single route instead of multiple specific routes. This reduces routing update size and processing load, which enhances scalability and stability in large networks. A common exam trap is confusing summarization with default routing or encryption. Summarization does not replace all routes with a default route, nor does it provide any security features like encryption. Instead, it aggregates routes to reduce routing table size. Practically, summarization helps keep routing tables manageable and reduces CPU and memory usage on routers, especially at distribution layers where many routes converge.
KKey Concepts to Remember
- Route summarization aggregates multiple contiguous IP prefixes into a single broader prefix to reduce routing table size and advertisement overhead.
- Cisco routers apply summarization at routing boundaries such as area borders in OSPF or autonomous system edges in EIGRP to improve scalability.
- Summarization reduces the number of specific routes carried in routing updates, which lowers CPU and memory usage on routers.
- Summarization does not eliminate subnet masks but uses a common mask that covers all summarized routes.
- Summarization does not replace all routes with a default route; it only aggregates routes with shared address bits.
- Routing protocols like OSPF and EIGRP support manual and automatic summarization to optimize route advertisement.
- Summarization helps prevent routing table explosion in large networks by limiting the number of entries routers must process.
- A common exam mistake is to confuse summarization with encryption or default routing, which are unrelated concepts.
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 aggregates multiple contiguous IP prefixes into a single broader prefix to reduce routing table size and advertisement overhead.
What is the correct answer to this question?
The correct answer is: It reduces the number of specific routes that must be carried or advertised. — The main benefit is that it reduces the number of route entries that must be advertised and stored. In practical terms, one broader summary can stand in for many smaller prefixes. That simplifies the routing table and can improve scalability, especially at aggregation points. Summarization does not eliminate all specific routing everywhere, but it helps keep the control plane cleaner. That is why it is widely used at distribution layers and routing boundaries.
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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