Troubleshooting and Maintaining Cisco IP Networks (TSHOOT, legacy) — Question 42

Which three features are benefits of using GRE tunnels in conjunction with IPsec for building site-to-site VPNs? (Choose three.)

Answer options

• A. allows dynamic routing over the tunnel
• B. supports multi-protocol (non-IP) traffic over the tunnel
• C. reduces IPsec headers overhead since tunnel mode is used
• D. simplifies the ACL used in the crypto map
• E. uses Virtual Tunnel Interface (VTI) to simplify the IPsec VPN configuration

Correct answer: A, B, D

Explanation

The correct answers A, B, and D highlight the benefits of GRE tunnels, such as enabling dynamic routing, supporting various protocols beyond IP, and simplifying access control lists. Option C is incorrect because while tunnel mode does encapsulate traffic, it does not inherently reduce overhead compared to transport mode. Option E, while beneficial, does not specifically relate to the advantages of using GRE with IPsec in the context of the question.