Could someone help with 4 please

Give forwarding tables for switches S1 to S4 in Figure 3.46. Each switch should have a default routing entry, chosen to forward packets with unrecognized destination addresses toward OUT any specific destination table entries duplicated by the default entry should then be eliminated. Consider the virtual circuit switches in Figure 3.47. Table 3.15 lists, for each switch, what (port, VCI) (or (VCI, interface)) pairs are connected to what other. Connections are bidirectional. List all endpoint-to-endpoint connections. In the source routing example of Section 3, 1.3, the address received by B is not reversible and doesn't help B know how to reach A. Propose a modification to the delivery mechanism that does allow for reversibility. Your mechanism should not require giving all switches globally unique names. Give forwarding tables for switches S1 to S4 in Figure 3.46. Each switch should have a default routing entry, chosen to forward packets with unrecognized destination addresses toward OUT any specific destination table entries duplicated by the default entry should then be eliminated. Consider the virtual circuit switches in Figure 3.47. Table 3.15 lists, for each switch, what (port, VCI) (or (VCI, interface)) pairs are connected to what other. Connections are bidirectional. List all endpoint-to-endpoint connections. In the source routing example of Section 3, 1.3, the address received by B is not reversible and doesn't help B know how to reach A. Propose a modification to the delivery mechanism that does allow for reversibility. Your mechanism should not require giving all switches globally unique names