Implementing Cisco IP Routing (CCNP ROUTE, legacy) — Question 353

How can you minimize unicast flooding in a network?

Answer options

• A. Set the router's ARP timeout value to less than the timeout value for Layer 2 forwarding table entries.
• B. Set the router's ARP timeout value to be the same as timeout value for Layer 2 forwarding table entries.
• C. Configure HSRP on two routers, with one subnet preferred on the first router and a different subnet preferred on the second router.
• D. Set the router's ARP timeout value to greater than the timeout value for Layer 2 forwarding table entries. B

Correct answer:

Explanation

The correct answer is B because having the ARP timeout value match the Layer 2 forwarding table entry timeout prevents premature removal of ARP entries, thereby reducing unnecessary unicast flooding. Options A and D would lead to mismatched timeouts, causing potential issues with packet delivery. Option C does not address ARP timeout settings and is unrelated to minimizing unicast flooding.