//gateway
document.writeln('<DIV> 	<dd>A device or a computer or a combination of special hardware and software that interconnects   <a href="../n/default.asp?name=network"> networks</a> with   the same or different incompatible communications <a href="../p/default.asp?name=protocol">protocols</a>. A gateway performs   protocol conversion to    translate one set of <a href="../p/default.asp?name=protocol"> protocols</a> to another,   for example, <a href="../t/default.asp?name=tcp_ip"> TCP/IP</a> to NetWare <a href="../i/default.asp?name=ipx"> IPX</a> and vice versa, from <a href="../a/default.asp?name=appletalk"> AppleTalk</a> to    DECnet, from SNA to AppleTalk and so on.   Gateways between <a href="../e/default.asp?name=email"> e-mail</a> systems allow users on different e-mail systems to exchange messages.   When a gateway connects two or more <a href="../n/default.asp?name=network"> networks</a> with the same   <a href="../p/default.asp?name=protocol">protocols</a>, it functions as an entry/exit point to the network. Transport protocol conversion may not be   required but some form of processing is typically   performed, see <a href="../p/default.asp?name=proxy_server"> proxy server</a>. Sometimes   <a href="../r/default.asp?name=router"> routers</a> can perform gateway functions.   In fact, gateway was an earlier name for <a href="../r/default.asp?name=router">router</a>.   </dd> </DIV>');