There's a clear upper limit simply based on the logic limitations for IP addressing - an IP address today nearly always consists of four octets (8-bit numbers), represented by 'a.b.c.d'. The maximum number that can be represent by 8 bits is 255. So the last octet, 'd' above, can address 256 devices. 0 is reserved, and the router uses one of those addresses, so 253 addresses can be generated by the router's DHCP service, i.e., 192.168.1.1 through 192.168.1.253. The router is most commonly at 192.168.1.254, while 192.168.1.255 is reserved for other functions (that i don't think are really used much any more, but no one uses them as addresses for devices.) Of course, traffic, MAC authorization tables mentioned elsewhere, and other things will likely kill your performance and growth capability long before you add a couple hundred devices. Too many connections will make your router slow-down, drop packets, refuse connections, and generally act in unhappy-making ways.