World of Ham Radio 1994 January/AMSOFT_1994.iso/packet/docs/packet07.doc

Text File | 1993-12-31 | 5.8 KB | 107 lines

INTRODUCTION TO PACKET - PART 7 - by Larry Kenney, WB9LOZ

W0RLI, N6VV, and VE3GYQ have devised a scheme called HIERARCHICAL
ADDRESSING.  With hierarchical routing designators we have an opportunity
to improve traffic routing.  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 @ BBScall.#local area.state-province.country.continent.

It might look complicated, but it's not.  First, note that each section of
the format is separated by a period.  Codes used for the continents and
countries are standards, now accepted throughout the world.  You should be
able to find a list of them in the file section of your BBS.  State and
province codes are the recognized two-character codes established by the
American 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.  The code for the
local area is optional, since most of you have no idea what code is being
used in upper New York state or in Iowa City, IA.  If you do know it,
please use it, since it will help get the message closer to where it's
going.  The code for Northern California is #NOCAL, and the code for
Southern California is #SOCAL.  You should use the appropriate one in the
signature line at the end of each message you send.  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 routing examples:
    WB9LOZ @ W6PW.#NOCAL.CA.USA.NA
    WB6LYI @ K6VE.#SOCAL.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 the Japanese network, and possibly other areas, 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 my
hierarchical address as an example, WB9LOZ @ W6PW.#NOCAL.CA.USA.NA, here's
how you would describe the address: "WB9LOZ at W6PW which is in Northern
California which is in California which is in the USA which is in North
America".

There are several BBS programs that implement hierarchical addressing now,
including the W0RLI, WA7MBL, AA4RE, MSYS and WD6CMU software.  Check the ID
block you receive when you log into your BBS.  If it has an H in it, such
as [RLI-11.11-CH$] or [4RE-02.10-HM$], your system supports it.

USING THE HIERARCHICAL ADDRESS: This next section explains how the BBS
software uses the hierarchical addressing scheme.  We first have to
understand how the software goes about matching items in the "@ BBS"
address with items in the forward file.  For an example, let's say that we
send a message to Tom, W3IWI, who operates his own BBS and is located near
Baltimore, Maryland.  We would enter:
     SP W3IWI @ W3IWI.MD.USA.NA
If the only entries in the forward file are California BBSs plus a list of
state abbreviations, let's see how the message would be forwarded.  The
first thing the software does is attempt to find a match between the items
in the forward file and the left-most item in the address field.  In our
case, it would not find W3IWI.  If there isn't a match, it then moves to
the next section to the right.  It would find MD and that match would allow
the message to be forwarded.  If it had found the call W3IWI, that entry
would take precedence (because it is more left in the field than MD) and
would of course also ensure delivery.

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
[e-mail] or from SMTP to [e-mail] 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."

Comments from W0RLI, N6VV and VE3GYQ.

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