What are some of the characteristics of Nokia's implementation of non-stop routing? (Choose two)

What are some of the characteristics of Nokia’s implementation of non-stop routing? (Choose two)

What are some of the characteristics of Nokia’s implementation of non-stop routing? (Choose two)
A . No protocol extensions required
B . Only supported by OSPF and IS-IS
C . Transparent to routing neighbors
D . Uses Graceful Restart to inter-operate with other vendors

Answer: A,C