Consistent means that, "If All the propositional formula in the system can be true simultaneously then that system is called Consistent."
Now Comes to the Questions, We can take,
P : The router send packets to the edge system
Q : Router supports the new address space
R : The latest software release is installed in the router.
Now we will get the following propositional formula
1) The router can send packets to the edge system only if it supports the new address space, ( P --> Q)
2) For the router to support the new address space it is necessary that the latest software release be installed. ( Q-->R )
3) The router can send packets to the edge system if the latest software release is installed. (R-->P)
4) The router does not support the new address space. (~Q).
Here, Take (P=F),(Q = F) and (R = F), All the Formula will be True. Hence This system is Consistent.