jamal,
you have to look at it from " service provider " angle. If you are client 1 and I allocate private ip, and since private ips' are not routable publicly, how will I support your connection? If you want private ips, then a separate router added to eg port 2 ( further subnetting ) will do the natting but reverse routes will be a problem unless router at port 2 passes the table to wan router.
secondly, WAN router connects to other routers on its Ethernet ports.
What if im client 1 and dont want to pay for a public IP.I simply want connection to the internet.If you assign private IP's on the WAN to Client 1 router.Should work?
How does WAN router connect to the Client routers ??