You need a protocol gateway that accepts data carried by one protocol and forwards it using another protocol. There are a number of ways to proceed and which is best depends on the problem you are trying to solve. For example, if you want to connect two geographically separated IPX/SPX LANs over the Internet, the method described in RFC1234 is easy to implement, particularly in Linux which has its own IPX/SPX stack. Novell also supports this, as does Cisco and others.
If you want to make an SNA-speaking mainframe available to PCs operating in a TCP/IP LAN, you can approach the problem from the LAN end using a product such as NetManage's RUMBA, or you can approach the problem from the mainframe end using IBM products as described, for example, in Internetwork Packet Exchange Support.
Finally, if you are looking for a general solution, there are standalone protocol gateways, such as the IDEA Concert Series from Argecy, that can convert among several protocols.
This was first published in October 2006