Hello,Enclosed is rather straightforward diagram of square network design.R-1 - R-2 |..........|R-3 - R-4Note: Please ignore the dots, since blanks/spaces are being removed.Addressing scheme:R1/R2: .0/30R1/R3: .4/30R2/R4: .8/30R3/R4: .12/30OSPF is ru...