The network consists of four loops connected in series. Each loop consists of two 1Ω resistors in series connected in parallel with two 2Ω resistors in series. Thus the effective resistance R of each loop is given by R1=21+41
giving R=(4/3)Ω.
Therefore, the equivalent resistance of the network = resistance of four loops connected in series, each having an effective resistance of (4/3)Ω=4×(4/3)=(16/3)Ω