pease solve this question please!! really stuck on this for a long time!! thank you

Q9 The two main functions of an Internet Protocol router are the forwarding of individual packets ("switching") and the maintenance of routing tables ("routing") (a) How and when are other routers involved in the internal forwarding decisions and actions of a router when it processes an individual packet (switching)? (4 marks) (b) Explain the behaviour of the class of routing protocols described as distance vector protocols (4 marks)