Cisco
352-001 · Question #226
352-001 Question #226: Real Exam Question with Answer & Explanation
The correct answer is C: configure Router B with a static route for the aggregate to Null0. A static route to Null0 for an aggregate prefix ensures the aggregate remains in the routing table for advertisement while preventing forwarding loops for unroutable destinations within the block.
Question
Refer to the exhibit. Which configuration change would maximize the efficiency of both the routing design and data forwarding plane in this topology?
Exhibit
Options
- Aconfigure Router B to advertise the more specific prefixes instead of the aggregate
- Bconfigure Router B to advertise the more specific prefixes in addition to the aggregate
- Cconfigure Router B with a static route for the aggregate to Null0
- Dconfigure Router A to advertise 10.0.0.0/8 instead of the default route to Router B
Explanation
A static route to Null0 for an aggregate prefix ensures the aggregate remains in the routing table for advertisement while preventing forwarding loops for unroutable destinations within the block.
Common mistakes.
- A. Advertising only the more specific prefixes instead of the aggregate eliminates route summarization benefits, increasing routing table size upstream and reducing forwarding efficiency.
- B. Advertising both more specific prefixes and the aggregate sends redundant routing information, unnecessarily bloating the routing table without any efficiency gain.
- D. Replacing a default route with a less specific aggregate (10.0.0.0/8) from Router A would only cover traffic destined to that single /8 block, losing the broad coverage and routing efficiency a default route provides.
Concept tested. BGP aggregate route black-hole static route to Null0
Community Discussion
No community discussion yet for this question.