300-420 Question 200
Select 3Your organization is designing a WAN solution that requires secure communication between two branch offices over the internet. Both branches need to encapsulate multiple protocols inside IP to ensure compatibility with the underlying network. You propose using a GRE tunnel. Which of the following considerations are true when deploying GRE in this scenario?
- A
GRE does not provide encryption and requires an additional protocol for securing the data.
- B
GRE tunnels support encapsulation of multicast and non-IP protocols.
- C
GRE tunnels can overcome MTU issues without requiring any adjustments.
- D
GRE requires the use of a routing protocol to establish the tunnel interface.
- E
GRE adds an extra header to the packet, which may require increasing the MTU size.
Show answer and explanation
Correct answers: A, B, E
Explanation
GRE is a tunneling protocol widely used in enterprise networks for encapsulating various types of traffic. While it supports multicast and non-IP traffic, it has no inherent encryption capabilities and relies on additional protocols like IPsec for security. GRE adds an extra header, which can lead to MTU-related issues if adjustments are not made. Understanding these characteristics is critical when designing secure, efficient network solutions using GRE.
- A. Correct.
Correct: GRE itself does not provide encryption, so for secure communication over the internet, an additional protocol like IPsec is required.
- B. Correct.
Correct: GRE supports encapsulation of multicast and non-IP protocols, which is a key advantage for applications like routing protocol exchanges over the tunnel.
- C. Incorrect.
Incorrect: GRE can lead to MTU issues due to the added header, and adjustments such as fragmentation or increasing MTU may be required.
- D. Incorrect.
Incorrect: GRE does not inherently require a routing protocol to establish the tunnel; it uses static configurations for source and destination IPs.
- E. Correct.
Correct: GRE adds a 24-byte header to the encapsulated packet, which may require increasing the MTU size or enabling fragmentation to avoid issues.