HIERARCHICAL ADDRESSING
Your Packet Address

Introduction to Packet Radio Part 7.

W0RLI, N6VV, and VE3GYQ devised a scheme called HIERARCHICAL ADDRESSING for message forwarding on packet. With hierarchical routing designators traffic routing is greatly improved. No longer will a missing call in a BBS forwarding file cause a message to remain unforwarded, sysops will no longer have to burn the midnight oil trying to keep their forward files up to date, and messages will move much more directly toward their destination.

The format for hierarchical routing is:

addressee-call @ BBS-call.#local area.state-province.country.continent

Example: W6FFF @ N6CKS.#SOCA.CA.USA.NA

It might look complicated, but it's not. First, note that each section of the format is separated by a period. State and province codes are the recognized two-character codes established by the US and Canadian Post Offices. These may be found in the Callbook, your phone directory, or any zip code listing. Don't guess on the state and province code if you aren't sure what it is, and make sure you use only the two-letter abbreviation.

You could send the message to the wrong state or province or keep it from being forwarded altogether. Codes used for the countries and continents are standards, now accepted throughout the world. You should be able to find a list of them in the file section of your BBS. The code for the local area is optional, since you probably have no idea what code is being used in upper New York state or in Iowa City, IA, for example. If you do know the local code, please use it, since it will help get the message closer to where it's going much more directly. The code for Northern California is #SOCAL, the code for Central California is #CENCA and the code for Southern California is #SOCA. For messages going outside of the US or Canada, the local area is again optional and the state-province is not used.

Using the hierarchical format, here are some examples:

KB6LQV @ N6ZGY.#NOCAL.CA.USA.NA KC6NVL @ K6VE.#SOCA.CA.USA.NA KC3XC @ N4QQ.MD.USA.NA VE3XYZ @ VE3RPT.ON.CAN.NA JA1ABC @ JA1KSO.#42.JPN.AS VK4AHD @ AX4BBS.AUS.OC

You'll note that the local area code is preceded by the octothorpe (now, how's that for a $5 word?), better known as the number or pound sign. The reason is that in Great Britain, Japan, and possibly other areas, they use routing numbers for the local area, which could get confused with zip and postal codes. Using the # on all local area codes will eliminate forwarding problems.

We need to emphasize two very important points: hierarchical addressing DOES NOT indicate a forwarding PATH, and ONLY ONE BBS call should be included in the address. A list of BBS calls separated by periods will not get your message to its destination. In fact, it can cause your message to loop between BBSs and your message probably won't be delivered. The addressing scheme is said to be one area inside another area.

Using a hierarchical address as an example, W6FFF @ N6CKS.#SOCA.CA.USA.NA, here's how you would describe the address: "W6FFF at N6CKS which is in Southern California which is in California which is in the USA which is in North America".

USING THE HIERARCHICAL ADDRESS: This section explains how the BBS soft-ware uses the hierarchical addressing scheme. For an example, let's say that we send a message to my friend Richard, KA7FYC, who uses the KD7HD BBS in Missoula, MT as his home BBS. We would enter: SP KA7FYC @ KD7HD.#MSL.MT.USA.NA

If the only entries in the forward file are California BBSs plus a list of state abbreviations, country and continent codes, let's see how this message would be forwarded. The the BBS software will attempt to find a match between the items in the BBS forward file and the various parts of the hierarchical address starting with the left-most item in the address field.

In our case, it would not find a match for KD7HD. If there isn't a match, it then moves to the next section to the right. It wouldn't find a match for #MSL, so it would again move to the right. Since all of the state abbreviations are listed in the forward file, it would find MT and that match would allow the message to be forwarded. The forward file would indicate the call of the next BBS in line to receive a message addressed to MT. Once the message is received at the next BBS, the process would start all over again until the message is finally delivered to its destination.

Here are some comments from the ones who devised the hierarchical addressing:

"There is another added benefit to this scheme. It involves Gatewaying between the BBS world and other networks, such as TCP/IP via SMTP. Much of the pioneer work in setting up the gatewaying protocols has been done by NN2Z, N3EUA, and PA0GRI, amongst others. The W0RLI BBS package allows for the forwarding of mail between the BBS world and the SMTP world. Of note is the fact that the WA7MBL package has allowed such message exporting and importing for some time now. This means that we can take advantage of the the TCP/IP host-names and their domain or hierarchal format for forwarding.

Thus it is possible to send mail from the BBS to VE3BTZ as [email protected] or from SMTP to [email protected] and not have any ambiguity.

"The authors hope that this paper will serve as a starting place for improved message routing by means of implicit routing. Low-level (VHF) BBSs need only maintain state or province or country codes for distant BBSs, and route such traffic to their nearest HF Gateway. In turn, the HF station routes it to the desired state, where the receiving Gateway station would have a detailed list of the BBSs it serves."


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