easyMultiple Choice
350-401 Practice Question: Is configuring BGP on a router that will be used…
A network engineer is configuring BGP on a router that will be used for BGP route summarization. The router receives multiple more-specific prefixes from its eBGP peers. The engineer wants to advertise a summary route to the iBGP peers without advertising the more-specific routes. Which command should the engineer use to suppress the more-specific routes while still installing them in the local routing table?
⚠ Common exam trap
Cisco often tests the distinction between suppressing routes from advertisement versus removing them from the local table, and candidates mistakenly think 'summary-only' removes the more-specific routes from the router, but it only suppresses their advertisement to BGP peers.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use the 'aggregate-address' command with the 'summary-only' keyword.
The 'aggregate-address' command with the 'summary-only' keyword in BGP creates a summary route from more-specific prefixes and suppresses the advertisement of those more-specific routes to BGP peers, while still keeping them in the local routing table. This meets the requirement of advertising only the summary to iBGP peers without removing the more-specific routes from the router's own RIB.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use the 'aggregate-address' command with the 'summary-only' keyword.
Why this is correct
The aggregate-address command with the summary-only keyword creates an aggregate route in the BGP table and, crucially, suppresses advertising all more-specific component routes to BGP neighbors. This reduces route-table size and the number of BGP updates while still ensuring reachability via the aggregate. Without summary-only, the aggregate is advertised alongside the specific routes, so the explicit summary-only keyword is required to achieve full suppression.
- ✗
Use the 'network' command to advertise the summary route.
Why it's wrong here
The network command advertises a prefix only if it is already present in the IP routing table as an exact match, and it does not, by itself, suppress any more-specific routes. Even if you configure the summary address with network, BGP will still send the individual more-specifics to peers unless you also filter them manually via a route-map or distribute-list. Thus, network alone cannot achieve summarization with suppression; it only performs route origination, not aggregation.
- ✗
Use the 'summary-address' command under the BGP address family.
Why it's wrong here
The summary-address command is a legitimate command in OSPF, where it creates a Type-3 summary LSA, but it has no meaning in BGP configuration. Under the BGP address family, Cisco IOS only recognizes aggregate-address for route aggregation and suppression. Issuing summary-address under BGP would produce a parser error or be rejected as an invalid command, making it an incorrect and unviable choice for this scenario.
- ✗
Use the 'redistribute' command to inject the summary route into BGP.
Why it's wrong here
Redistribute injects routes from another protocol into BGP, but it does not create an aggregate route in the BGP table nor does it inherently suppress more-specific routes. To achieve summarization via redistribution, you would need a complex route-map with a network statement to filter specifics, which is highly error-prone and still does not provide the automatic suppression behavior of aggregate-address summary-only. This method is neither direct nor recommended for BGP summarization, and it would inadvertently advertise all specific prefixes unless additional filtering is configured.
Go deeper
Related to this question
About these practice questions
Courseiva writes every 350-401 question from scratch — 1,923 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.