CompTIA Network+ (N10-008) — Question 230

Due to concerns around single points of failure, a company decided to add an additional WAN to the network. The company added a second MPLS vendor to the current MPLS WAN and deployed an additional WAN router at each site. Both MPLS providers use OSPF on the WAN network, and EIGRP is run internally. The first site to go live with the new WAN is successful, but when the second site is activated significant network issues occur. Which of the following is the MOST likely cause for the WAN instability?

Answer options

• A. A CDP neighbor has changed
• B. Asymmetrical routing
• C. A switching loop
• D. An incorrect IP address

Correct answer: B

Explanation

The correct answer is B, as asymmetrical routing can cause packets to take different paths back and forth, leading to instability in the network. The other options are less likely to cause widespread issues; for example, a CDP neighbor change (A) is more of a notification than a cause of instability, a switching loop (C) typically results in a broadcast storm rather than route instability, and an incorrect IP address (D) would usually lead to a specific connection failure rather than widespread WAN issues.