JNCIS-ENT: Juniper Networks Certified Specialist – Enterprise Routing and Switching (2023) — Question 42

You configured a GRE tunnel that traverses a path using default MTU settings. You want t o ensure that packets are not dropped or fragmented. In this scenario, what is the maximum packet size that would traverse the GRE tunnel?

Answer options

Correct answer: A

Explanation

The maximum packet size for a GRE tunnel is 1476 bytes, which accounts for the standard 20 bytes of the IP header and 8 bytes of the GRE header, keeping the total under the typical Ethernet MTU of 1500 bytes. The other options exceed this calculated limit, which would lead to fragmentation or dropping of packets in the GRE tunnel.