- GRE does not have strong security mechanisms.
- The GRE header alone adds at least 24 bytes of overhead.
- GRE is stateless.
- GRE encapsulation supports any OSI Layer 3 protocol.
- GRE is the most secure tunneling protocol.
- GRE provides flow control by default.
Explanation: GRE uses a protocol type field in the GRE header to support the encapsulation of any OSI Layer 3 protocol. GRE itself is stateless; it does not include any flow-control mechanisms by default. GRE does not have strong security mechanisms.
More Questions: CCNA 4 Chapter 3 Exam Answers