I just wonder that we can design a simple router or even bridge with the 8051 base microcontroller.
May be we can put simple bios and TCP/IP protocol and put the UTP port. We can configure it from the remote PC via TCP/IP.
serial
Example application that transfers data from the serial line over TCP/IP. Uses a higher version of the library with compiled serial line, "telnet" client and HTTP server support.
The result is an ETHERNET to RS232 converter, configurable over a WWW interface, with complete TCP/IP implemented - see "Telnet" Setup example.