Network topology and Smart cards

Current technology credit cards make a call to the clearing bank.  What does that call giet them? It checks the card against a valid card list to reduce fraud.  It then records the transaction, and the clearing bank likely clears all transactions at the end of the day. The store owner only needs a few gig of memory to store all the valid cards he/she is likely to see.  So why not move the clearing house software down to the store owners terminal machine?   Walmart should, for example, simply run their own clearing function at each store, then batch them up to headquarters at the end of the day.

The fraud detection is just as secure, the store owner need only update his valid list every so often.  If he has a suspicious customer then simply hit the connect button, or take the risk.

Companies like WalMart do not even need a clearing function, they can locally transfer sales gross to their own card and use that to make payments on inventory. Whether paper of plastic, eventually someone goes to the bank.  Smart cards allow the store owner to vary the number of trips to the bank to suit their needs. Smart card is a functionality, it disconnects the bank inventory cycle from the store owners inventory cycle. Hence the store owner is much more accurate because his money rates match his inventory cycle and he knows, almost instantaneously,  what his current net becomes.