Which VPN protocol has the highest overhead?

Question

Options

• AGRE over MPLS
• BIPsec with NAT Traversal
• CSecure Vector Routing
• DIPsec without NAT Traversal

• A
  3% (2)
• B
  80% (51)
• C
  5% (3)
• D
  13% (8)

Explanation

IPsec with NAT Traversal carries the highest overhead because it stacks two layers of encapsulation: the standard IPsec ESP/AH headers for encryption, plus an additional UDP header (port 4500) that wraps the entire IPsec packet to traverse NAT devices. This double encapsulation results in more bytes added per packet than any other option listed.

• GRE over MPLS (A) is wrong - GRE adds a lightweight 4-byte header, and MPLS uses small label stacks; combined overhead is significant but less than IPsec+NAT-T.
• Secure Vector Routing (C) is wrong - SVR (used in Juniper's Session Smart Networking) is explicitly designed for minimal overhead and efficient session-based routing.
• IPsec without NAT Traversal (D) is wrong - IPsec alone adds encryption headers, but removing the UDP NAT-T wrapper means one fewer encapsulation layer compared to option B.

Memory tip: Think of NAT Traversal as putting an already-sealed envelope (IPsec) inside another envelope (UDP) just to get it through a mail sorter (NAT) - more envelopes always means more weight.

No community discussion yet for this question.