CCNA: Cisco Certified Network Associate — Question 86

What mechanism carries multicast traffic between remote sites and supports encryption?

Answer options

• A. ISATAP
• B. IPsec over ISATAP
• C. GRE
• D. GRE over IPsec

Correct answer: D

Explanation

The correct answer is D, GRE over IPsec, because it allows for the encapsulation of multicast traffic in GRE tunnels while also applying IPsec for encryption. Option A, ISATAP, is a tunneling protocol but does not provide encryption. Option B, IPsec over ISATAP, uses ISATAP for tunneling but lacks direct multicast support. Option C, GRE, can encapsulate multicast traffic but does not inherently provide encryption.