Queueing networks in wich the stations have finite buffers are found in models of complicated communications and manufacturing systems where an exact analysis is often formidable. We consider various queueing medels that can be used as building blocks in the approximate amlysis of some feed forward queueing networks. The basic model is a tandem configuration of queues with finite buffers in between. The arrivals to the first queue are a Poisson stream and the service times at the queues are expoentially distributed. There are finite buffers in between the queues and hence a blocking mechanism has to be enforced. We obtain approximatiom for average queue lengths at each queue and the stability condition for the network, We then consider severed extenions. Numerical examples comparing the approximate solutions to those obtained via simulation and exact methods show that the approximation is good for a broad range of parameters.