A network diagram is given below. AS3 and AS2 use OSPF as the intra-AS routing protocol. AS1 and AS4 use RIP as the intra-AS routing protocol. EBGP and iBGP protocols are used for Inter-AS routing throughout the entire network. Answer the options a, b, c and d considering this diagram. There is no physical connection between AS4 and AS2.

a) With what protocol does the 3c router learn the existence of the x network?

b) With what protocol does router 1c learn the existence of network x?

c) Assume that the physical connection between AS4 and AS2 is established. Should AS2 necessarily report this newly formed alternative route to other neighbors to reach x? Explain.

d) Assume that the physical connection between AS4 and AS2 is still established. If the Hot Potato Routing method is used, which of the routes offered over 3a and 3c will the 3b router choose? Explain. (Assume the cost of link 3b-3c is 10, and the cost of link 3b-3a is 3.)

4b 4a 36 AS4 20 3b 10 2b 1b AS3 1a AS2 1d 12 AS1