After the recent implementation of a new design that incorporated GRE tunnels into the network, the network operations staff is seeing the following syslog message in multiple routers on the network - %TUN-5-RECURDOWN: Tunnel0 temporarily disabled due to recursive routing.
From a design perspective, what was not taken into account prior to implementing the solution?
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A. B. C. D. E.D.
The syslog message %TUN-5-RECURDOWN indicates that a tunnel interface on the router has been temporarily disabled due to recursive routing. Recursive routing occurs when a router receives a packet with a destination address that matches the IP address of a tunnel interface, and the router routes the packet back out of the same tunnel interface. This results in a loop, which can cause network instability and connectivity issues.
To prevent recursive routing, the router should not learn routes to the tunnel destination address through the tunnel interface. This can be achieved by implementing a static route to the tunnel destination address, or by using a dynamic routing protocol that advertises the tunnel destination address out of a different interface.
Therefore, from a design perspective, option D, "The router is learning the route to the tunnel destination address using the tunnel interface" was not taken into account prior to implementing the solution. The router needs to be configured to learn the route to the tunnel destination address through a different interface to avoid recursive routing and prevent the tunnel interface from being temporarily disabled.