Which two statements are true about IP-IP tunnels on Junos devices? (Choose two.)
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A. B. C. D.AD
IP-IP tunnels support only IP traffic, and add an additional 20-byte header to a packet. They use the interface name ip, and each interface is point-to-point.
A. They support only IP traffic: This statement is true. IP-IP tunnels, also known as IP-over-IP tunnels or GRE tunnels, support only IP traffic. They encapsulate packets of one IP protocol version (IPv4 or IPv6) within another IP protocol version. For example, an IPv4 packet can be encapsulated within an IPv6 packet to traverse an IPv6 network.
B. Tunnel endpoints use the interface ipt: This statement is false. The correct interface for IP-IP tunnels is usually a logical tunnel interface (lt-) rather than a physical interface. The lt- interface is used as the tunnel endpoint, which can be configured with an IP address and other parameters, such as tunnel mode, TTL value, and fragmentation.
C. They add no additional overhead to packets: This statement is false. IP-IP tunnels add additional overhead to packets due to encapsulation and decapsulation. The original IP packet is wrapped with a new IP header, which includes the tunnel source and destination addresses. The encapsulated packet is then sent over the tunnel, where it is decapsulated and the original packet is delivered to its final destination.
D. Each tunnel interface is point-to-point: This statement is true. IP-IP tunnels are typically point-to-point connections between two endpoints, and each tunnel interface represents a single point-to-point link. The tunnel interface can be configured with a remote IP address, which identifies the other endpoint of the tunnel. The tunnel can also be configured to use dynamic or static routing to exchange packets between the endpoints.