Question & Answer: From the above we can conclude that S2 must be directly connected to both S1 and S3 as its table lists them as next_h…..

Suppose we have switches S1 through S4; the forwarding-table destinations are the switches themselves. The tables for S2 and S3 are as below, where the next_hop value is specified in neighbor form:

S2: 〈S1,S1〉 〈S3,S3〉 〈S4,S3〉

S3: 〈S1,S2〉 〈S2,S2〉 〈S4,S4〉

From the above we can conclude that S2 must be directly connected to both S1 and S3 as its table lists them as next_hops; similarly, S3 must be directly connected to S2 and S4. (a). The given tables are consistent with the network diagrammed in exerise 4.0. Are the tables also consistent with a network in which S1 and S4 are not directly connected? If so, give such a network; if not, explain why S1 and S4 must be connected. (b). Now suppose S3’s table is changed to the following. Find a network layout consistent with these tables in which S1 and S4 are not directly connected. S3: 〈S1,S4〉 〈S2,S2〉 〈S4,S4〉 While the table for S4 is not given, you may assume that forwarding does work correctly. However, you should not assume that paths are the shortest possible; in particular, you should not assume that each switch will always reach its directly connected neighbors by using the direct connection.