Defining an internet gateway can be confusing to some folks - there is some new terminology, and before we go further, we had best define what a gateway is and it's close cousins.
An interactive gateway allows users to connect to the internet through packet radio and utilize the many services found there. In some cases, access is limited to "Amateur Only" sites, still others will allow full access (well, all except the sites that are not appropriate for the air). This gateway also will go "the other way". Users can log in via the Internet, and have access to the radio network. Potential packeteers can get a taste of this mode before they lay out money for this equipment. This type of gateway usually greets the logged-on user with a conventional BBS interface. Most of these gateways use TNOS or JNOS to perform the linkage to the Internet.
Aside from the BBS commands you are used to seeing (like Send, Read, Kill, List, etc.), there will be a few unfamiliar ones (like telnet). Most interactive gateways will support AX.25, Net/Rom (TheNet), TCP/IP and round-table discussions, similar to the "Internet Relay Chat". You may send and receive E-Mail through the internet, through the BBS network, connect up to distant Amateur sites on the internet, and use it as a conventional Network Node on radio or the internet. In that sense, the commands mirror the nodes that you are used to.
Some of these interactive gateways also provide this "wormhole" service that treats a distant node as just another node on the network. New York becomes just as local to the network as "the next town over" when using a wormhole in this manner.
Another type of gateway is the dedicated point-to-point wormhole gateway. Unlike a fully interactive gateway, it is limited to providing this "wormhole" service only and is not intended to provide users with full access to the internet. It becomes a bridge to complete a radio network. For example, there could be a wormhole between a system in Milwaukee and one in Florida. The goal is a seamless linkage between two user LANs in different parts of the country. This has generated a bit of controversy, as the Tuscon Amateur Packet Radio Association (TAPR) has been promoting the idea of using the internet to complete the national packet radio network in this manner.
Mail Forwarding Gateways do not provide real-time access to the internet, and it does not complete a radio network on a real-time basis. Rather, it is used by two BBS's to exchange mail via the internet. Most often, this is used when radio paths are unreliable or unavailable. This practice has been the subject of controversy as well. While we will not attempt to enter the controversy in this column, the explanation should help you understand what each service is and may help you understand the debate better.
Now that we know what types of gateways have found use, we can talk about how they are constructed. It is not too hard to understand, but it is not your typical packet station. Let's talk about the first case, a fully interactive internet gateway.
Any type of gateway is constructed with two or more "ports". One will go to the internet and may well be a phone modem, or it could be a network "ethernet" card hooked up to some kind of network that eventually reaches the internet. In any case, this port allows an interface with the internet. The other ports are connected to a node stack, or become a node stack.
It is possible for one of these computers to act as a full node and network router. In the case of the machine being tied to a node stack, the serial port of the computer is "multiplexed" into the serial ports of the TNC's. This is the same situation as a normal node stack - the computer is just treated as another TNC. In the case of the computer performing the task of a node stack, the TNC's are connected to serial ports of the computer. The TNCs operate in KISS mode and the computer software does all of the work normally reserved for the node firmware. From there, the rest of the node stack - radios, antennas, etc - are the same as in a conventional node stack. So the internet gateway can either replace the normal node firmware, or augment it.
Now that we have our look at gateways, we will further explore how to use them in the next installment of "Using the Wisconsin Network".
On to Part 36 - Internet Gateways - Part 2
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