Which of the following descriptions about route aggregation in BGP are correct? (Multiple choice)

Question

Options

• AYou can manually generate aggregate routes in the BGP view through the aggregate command.
• BBGP route aggregation by automatic aggregation also generates BGP routes advertised by manual aggregation.
• CYou can use the summary automatic command to generate automatic summary routes.
• DWhen performing aggregation through the aggregate command, add the keyword detail-suppressed to advertise both the aggregate route and the detailed route to the peer.

• A
  74% (17)
• B
  26% (6)

Explanation

A is correct because the aggregate command, used in the BGP view, is the standard way to manually configure aggregate (summary) routes, giving administrators explicit control over which prefixes are summarized.

C is correct because summary automatic enables automatic route summarization in BGP, causing the router to summarize routes to their classful network boundaries - a quick but less granular approach compared to manual aggregation.

B is wrong because automatic aggregation (summary automatic) and manual aggregation (aggregate) are completely independent mechanisms that produce different results - automatic summarizes to classful boundaries, while manual uses administrator-defined prefixes. They do not generate the same BGP routes.

Important note on D: The answer key marks D as correct, but the description is actually inverted from standard behavior. In Huawei VRP, detail-suppressed causes the router to advertise only the aggregate route and suppress the specific (detailed) routes - not advertise both. Without detail-suppressed, both the aggregate and the specific routes are advertised. If your exam source differs, verify against your study material's vendor documentation.

Memory tip: Think of detail-suppressed literally - it suppresses the details, leaving only the aggregate visible to peers. And remember that automatic and manual aggregation are two separate tools that don't overlap: one is classful and hands-off, the other is prefix-specific and deliberate.

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