International Guideline

From Digital Traffic System
Revision as of 11:51, 3 August 2019 by DL4FN (talk | contribs) (Useful links)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Introduction

Traffic handling is a part of amateur radio most popular in the United States and Canada. In recent years interest in traffic handling grew in other parts of the world as well mainly driven by emergency communications needs. Today, regularly operated traffic links are established between North America, Europe, and Oceania.

The nucleus for this evolvement was the extension of the US digital traffic system (formerly known as NTSD) to Europe in 2013 which is mainly thanks to David Struebel (WB2FTX) the RRI Eastern Area Digital Coordinator.

Both technical and operational standards are needed to successfully operate international traffic links and we therefore discuss the following three main topics in the subsequent sections:

  • regulatory aspects - which traffic is allowed to be exchanged
  • message formats - different customs and practices are in place in different regions
  • operations - technical and operational aspects of traffic exchange.


The big picture

Before we dig into the details we give a coarse overview to understand the main ideas first. Our basic philosophy is:

Be conservative in what you do, be liberal in what you accept from others. (Jon Postel, RFC 761, 2.10)


What is international traffic?

International traffic literally means messages the originator and recipient of which are located in different countries. However, most traffic handlers will not regard a message from the US to Canada as "international" because the same traffic system (RRI/ NTS) and operating procedures are used in both countries.

Those geographical areas with their own traffic system(s), message routing, and operating procedures are called Traffic System Areas in the remainder of this document. They do not necessarily follow continental boundaries, think e.g. of Hawaii and Guam. Currently we have three such traffic system areas: RRI/ NTS in North America, the European traffic system, and the Oceania traffic system.

Thus international traffic is merely the exchange of traffic between different traffic system areas. Most traffic handlers are confident that their own system works but are uncertain about the interplay with the others. Therefore:

Be friendly. Service messages back frequently in particular to stations originating low levels of international traffic.


Which traffic to send

Please send amateur to amateur traffic only and refrain from sending third-party traffic except for emergencies.

This rule is to be obeyed for all international traffic and the control operator at the station of origin is responsible for enforcing it. Messages violating this rule may be discarded and serviced back accordingly. However, if you encounter the rare case of receiving a message for a third party check whether this particular piece of traffic is in accordance with your local regulations.


Message forms

The IARU message form which is akin to the NTS/ RRI message form is the IARU standard for international traffic and most NTS/ RRI radiograms comply with it anyway. For the subtle details see below. However, there are traffic nets on the world which prefer to use different message forms (think of a group of former maritime radio officers). Best follow these two rules:

  • when originating a message use the IARU format whenever possible
  • when interfacing with manual nets convert messages to the local form only if absolutely necessary.

It is recommended that traffic handlers involved with international traffic know and support the IARU message form as the lowest common denominator.


Routing international traffic

Traffic Systems inter-communicate with each other through dedicated gateway stations which have mutual skeds either for manual or unattended automatic operation. Each Traffic System has its own way to route international traffic to it's gateway stations. Submitting your message to a Digital Traffic Station is the easiest way to send international traffic as we now have a (flexible and easily extensible) international address scheme and your message will find it's way without any further work from your side.


Manual operations

Nets usually come with a set of standard operating procedures published by the net manager. This also holds true for international traffic nets. Just play by the rules.

If you have an international traffic sked either in telegraphy or phone best use the Q signals and abbreviations defined in the ITU Radio Regulations and it is recommended to employ the operating procedures for traffic exchange in the maritime mobile radio service.

In particular do not use QN signals unless you are absolutely sure that your partner station is able to operate by them.

Before you send any international traffic make sure that it is compliant with your local regulations. Amateur-to-amateur traffic is always permitted.


Digital operations

If you operate a Digital Traffic Station (DTS) submit all your international traffic to your home MBO which knows where to route it. When in doubt get in contact with your MBO sysop or an official of your digital traffic system.

When submitting an international message to your MBO first check that the message is compliant with your local regulations. Amateur-to-amateur traffic is always permitted. Then double check that the digital address is correct.


The fineprint

Which traffic to send

Rules all the way

An international message makes its way through several intermediate stations and it is subject to all the regulations on its way. Think for example of a message from a radio amateur in Canada to another radio amateur in Great Britain which is typically subject to regulations in Canada, the USA, Germany, and Great Britain.

The below section on international regulations explains how it is possible to have international traffic under these conditions.

Except for emergencies the FCC requires a special agreement between the US and the other country to allow for traffic with non-amateurs usually referred to as third parties. Third-party traffic (i.e. traffic on behalf of third parties) is generally not allowed in international communications.

You can find a list of countries having a third-party traffic agreement with the US on the ARRL website. Please note: Although this shows a third party agreement with the UK it is restricted to those stations with a GB callsign. Those are usually special event stations. Hence these are the only UK stations allowed to exchange third party traffic with the US.

However, virtually all countries (in particular including the US and Germany) allow for international amateur to amateur traffic. This is due to international regulations described below.


Details on FCC rules

The FCC rules define third-party traffic as "a message from the control operator (first party) of an amateur station to another amateur station control operator (second party) on behalf of another person (third party)." (FCC 97.3, Definition 47). Note that being a "control operator" is FCC speech for having a valid amateur radio license.

The FCC rule on third-party traffic (FCC 97.115a) is a bit lengthy and says in a nutshell that

  • international third-party traffic requires a special agreement between the US and the other country except for emergencies
  • international amateur to amateur traffic is not third-party but second-party traffic

Find the full text (bold font by the page author) below.

97.115 Third party communications.
(a) An amateur station may transmit messages for a third party to:
(1) Any station within the jurisdiction of the United States.
(2) Any station within the jurisdiction of any foreign government when transmitting emergency or disaster relief communications and any station within the jurisdiction of any foreign government whose administration has made arrangements with the United States to allow amateur stations to be used for transmitting international communications on behalf of third parties. No station shall transmit messages for a third party to any station within the jurisdiction of any foreign government whose administration has not made such an arrangement. This prohibition does not apply to a message for any third party who is eligible to be a control operator of the station.

Thus amateur to amateur messaging/ communication is clearly defined as second party communications. Together with the statement that the prohibition of third party traffic does not apply for any third party who is eligible as a control operator (i.e. has a valid amateur radio license) clearly shows that any amateur to amateur communications is second party and does not depend on the location or jurisdiction of any station. Any direct amateur to amateur communications is clearly not third party.


Background on international regulations

With every country establishing her own rules on the operation of communication systems the regulations of two countries will hardly ever match and allow for international communications. Mutual agreements between some hundred countries are obviously not a good idea to mitigate this. Therefore international communications (except for the internet) have been governed by international conventions since the 1860s. Today the Constitution and Convention of the ITU are common ground for the national administrations to establish regulations on international communications. The ITU "Member States are bound to abide by the provisions of this Constitution, the Convention and the Administrative Regulations in all telecommunication offices and stations established or operated by them which engage in international services" (Constitution and Convention of the ITU, Nr. 37, 2011 ed.).

One of these "Administrative Regulations" alluded to above are the Radio Regulations (RR) which "shall be binding on all [ITU] Member States" (Const. and Conv., Nr. 31, 2011 ed.). They contain all international rules on radio and define the amateur radio service as "a radiocommunication service for the purpose of selftraining, intercommunication and technical investigations carried out by amateurs" (RR 1.56, 2004 ed.).

The key term here is intercommunication which means that radio amateurs are communicating with each other only. Non-amateurs are referred to as third parties although this term is not defined by the Radio Regulations. According to the RR "Amateur stations may be used for transmitting international communications on behalf of third parties only in case of emergencies or disaster relief." (RR 25.3, 2004 ed.).

Summing up the standard on international communications in the amateur radio service is amateur to amateur traffic which should be allowed for by all ITU member states. You are expected to find this rule (or an even less restrictive version) in all national regulations on amateur radio.


The IARU message form

The IARU message form is the preferred form to exchange international traffic. Convert to a local message form only if absolutely needed and as late as possible in the message path i.e. retain the original message (form) as long as possible.

We assume that you are already familiar with either the RRI/ NTS or the IARU message form. The latter is more or less a subset of the first so a valid IARU message is also a valid RRI/ NTS message. Therefore the following sections describe the slight differences between both forms mainly from the perspective of the RRI/ NTS form.


Preamble

The preamble is the part of the message hat differs most between the two message forms.

The parts of the preamble are: prosign (optional), message number, precedence, handling instructions (RRI/ NTS only), station of origin, check, place of origin, time (optional in RRI/ NTS), month, and day.


Prosigns and message numbers

NR is an optional prosign in both the RRI /NTS and the IARU message form. However, no other prosigns are defined for the latter form which implies in particular that international service messages are not sent as SVC. Send them as regular messages instead. It will be clear from the message text anyway that your message is a service message. You may use SVC (or the seldomly used ITU signal XQ if you want to confuse the recipient) in the text part if you like.

It is recommended to issue message numbers on a per-year basis. This avoids confusion when tracking individual messages.


Handling instructions

Handling instructions (HX codes) are not part of the IARU standard. They are optional in the RRI/ NTS form and the ubiquitous HXG is rarely useful in international traffic. The most needed and useful instructions are HXC and HXE. Either use op notes following the recipient's address or the message text itself to replace theme e.g. "OP NOTE REPORT BACK TIME OF DELIVERY".

The official (five-character) codes for the public telegram service defined in ITU-T recommendation F.1 come in handy here but they are not used in the amateur radio service.


Message precedence

Only the three precedences R(outine), P(riority), and E(mergency) are defined in the IARU standard. Therefore international welfare traffic has to be either sent as R or P. Furthermore, although the IARU standard defines the single letter E for emergency we recommend to spell out the word completely (EMERGENCY) in the preamble as it might easily be missed or mis-interpreted with weak CW signals.

Note that TEST precedences are not in the IARU standard which means that it must be made very clear by using the word TEST or EXERCISE at the start and end of the text part in those messages this this is practice traffic.


Callsign and word count

The callsign field is for the callsign of the station of origin, the first station that puts the message into the traffic system. Service messages go to this callsign. This is identical in both message form standards.

The word count (check) is the number of words in the text part of the message regardless of their length (commercial telegrams had a different count for words with 10 characters and more). Groups of characters separated by spaces are considered as words. If you receive a message the check of which is much larger than expected consider that the sender may have included the address part in the word count.

On reception of a message the word count has to be checked by the receiving station. Although there is no statement in the IARU standard about the correction of the check we recommend to use the RRI/ NTS procedure which leaves the original (wrong) check and amends a slash and the corrected word count.

Note that since ARL codes are not internationally recognized the word count in international messages is always a number (not ARL followed by a number).


Place of origin

In both message form standards the place of origin is the location of the party for whom the message is created which is not necessarily the location of the station of origin. In the US and Canada the city name and state/ province abbreviation is used for the place of origin e.g. CONCORD MA.

City names may contain slashes e.g. FRANKFURT/MAIN for the city of Frankfurt at the river Main in Germany and FRANKFURT/ODER for the city with the same name at the river Oder.

Stations outside the US and Canada are requested to use the city name and the ISO 3166 3-letter country code for this field, e.g. FRANKFURT/MAIN DEU. The section on digital messaging below has a table with popular country codes.


Time and date

The time field is optional in the RRI/ NTS form and mandatory in the IARU form where it contains the UTC time of the message creation with four digits from 0000 to 2359, e.g. 1234. Note that UTC is always implied and that there is no indication of whatever time zone (Z, L, etc.).

The date field is the same for both formats with the three-letter abbreviation of the month (JAN, FEB, etc.) and the day number (with no leading zeroes) separated by a space.


Address

Punctuation and special characters

Punctuation is not used in the address part of a message with the exception of /. All other characters are either to be omitted or replaced with their literal tokens (DASH, COMMA, COLON etc.)

Many foreign languages have additional characters besides A...Z. Diacritic characters are to be replaced with their stem characters respectively except for German umlauts which are transliterated according to the following table.

Umlaut Transliteration
ä Ä AE
ö Ö OE
ü Ü UE
ß SS

So the address line "Straße zum Löwen 16" becomes "STRASSE ZUM LOEWEN 16".


Callsign

Please always mention the recipient's callsign after the name to assure those handling your message that it is destined to a radio amateur. The above section on acceptable traffic explains why this is important.

Name and callsign e.g. "PETER DL4FN" are often sufficient to reach well-known traffic handlers outside North America. When in doubt try to find out a postal address with qrz.com or one of the callbooks accessible through the NG3K website.

In case you route your message through some other station mention its callsign at the end of the first address line with c/o, e.g. PETER DL4FN C/O KW1U and send your message to KW1U who will forward it to DL4FN.


Phone numbers and email addresses

Address data other than the postal address (phone, email) is always placed after the postal address and an indicator of the address type may be used for clarity, e.g. TEL (telephone), FAX (FAX machine), or EMAIL (electronic mail).

The notation of international phone numbers is defined in ITU-T recommendation E.123 but it is usually sufficient to place numbers into groups of 3 or 4 numbers each.

For messages to the US and Canada always try to find out the recipient's phone number and put in the last line in the form 012 345 6789. Use the token NO PHONE if you cannot find out a phone number.

For messages destined elsewhere do not waste your time to figure out phone numbers. They are often not publicly available for privacy reason and the delivering station best knows how to find out.

In email addresses replace @ with ATSIGN, a dot with the word DOT, and concatenate the parts with spaces. Thus james.bond@mi5.gov.uk becomes JAMES DOT BOND ATSIGN MI5 DOT GOV DOT UK.


Op note

An op note may follow the address part with useful information for handling operators e.g. message routes or details on delivery. Be concise in op notes and use well-known signals and abbreviations for brevity and clarity.


Text

The parts of the message text are to be separated with the letter X . The use of the English word STOP may cause confusion in some messages and should be avoided. Because the ARRL message form has a maximum of 25 words this is often considered to be the limit for messages to the US and Canada.

Although the IARU message form does not specify a maximum limit of words in the text part be concise and do not use unnecessary words.

English is a foreign language for most people on the world. Therefore use simple words when you are not sure about the language capabilities of the message recipient.

For test and exercise messages use the words TEST MESSAGE or EXERCISE at least at the start of the text part.

Note that ARL codes are not known outside the US and Canada and avoid them in international messages.


Signature

The signature is the name of the person for whom the message was created. As this person's location is the place of origin in the preamble no location needs to be specified in the signature. Add the callsign of the signing party if it is a radio amateur.

When sending traffic from the US to international destinations keep in mind that abbreviations related to the ARRL field organization (SM, STM, OO etc.) are rarely known outside the US. Use longer explanatory versions instead e.g. "SECTION TFC MGR" instead of STM.


Example messages

A message from the US to Europe

Consider the following international sample message:

    NR 1234 R KD3QV 13 GRANTHAM NH 1300 DEC 24
    PETER DL4FN C/O KW1U
    CONCORD MA 01742
    OP NOTE REPORT BACK TIME OF DELIVERY
    =
    WISHING YOU AND YOUR FAMILY
    A MERRY CHRISTMAS AND A
    HAPPY NEW YEAR
    =
    FRITZ KD3QV

Remarks:

  • in the preamble note the time field without the Z
  • the first address line has a C/O and the address is the one of KW1U
  • the op note replaces the HXC handling instruction
  • no ARL code is used in the message text
  • the signature contains the callsign of the sender

Associated service messages for this may be:

    SVC 345 R KW1U 9 CONCORD MA DEC 24
    FRITZ KD3QV
    GRANTHAM NH 03753
    =
    UR NR 1234 DL4FN SENT
    DB0NTS DEC 24 1600Z
    =
    KW1U

As a message from KW1U to KD3QV is inside the US the RRI/ NTS form is used here. When DL4FN receives the message he reports back using the IARU form:

    3456 R DL4FN 8 ERBACH/ODW DEU 1630 DEC 24
    FRITZ KD3QV
    GRANTHAM NH 03753
    =
    UR NR 1234 RCVD DEC
    24 1600 UTC
    =
    PETER DL4FN
  • the prosign SVC is not used as it is not part of the IARU form
  • the three-letter country code DEU for Germany is used with the place of origin
  • the UTC time of message creation is part of the preamble


A message from Europe to Oceania

Consider the following message from a Simulated Emergency Test:

    NR 456 P ZL1XYZ 27/22 AUCKLAND NZL 0600 OCT 4
    GREG MOSSOP G0DUB
    CHESTER
    ENGLAND
    OP NOTE ROUTE VIA WB8WKQ
    =
    TEST MSG X THANKS FOR
    YOUR NR 313 X FUEL
    COSTS ARE GOING UP BUT
    STOCKS ARE HOLDING HERE X
    TEST MSG
    =
    SOME ONE ZL1XYZ

Those test messages are typically sent with priority TEST P when using the RRI/ NTS form but as this priority is not available in the IARU form the message text starts and ends with the words TEST MSG.

The message originator included the address part in the check (27) which was later corrected to only consider the message text (22) and the original check was kept (strictly speaking the IARU form does not specify what to do with corrected checks).

When the message was received at the European message hub a service message was issued:

    3457 R DL4FN 20 ERBACH/ODW DEU 2035 OCT 7
    SOME ONE ZL1XYZ
    AUCKLAND
    NEW ZEALAND
    =
    REF UR 456 X RCVD
    AT DF0NTS FM WB8WKQ OCT
    5 2035 UTC X SENT
    G4KUJ OCT 7 1937 UTC
    =
    PETER DL4FN SYSOP DB0NTS/ DF0NTS

REF references a(nother) message which is usually sufficient to indicate a service message.

There may be additional service messages from stations handling the original message. Be generous with issuing service message to foster confidence in international traffic handling.


Routing and handling international traffic

Routing international traffic

Message exchange between traffic systems is performed through dedicated gateway stations which have mutual skeds with each other and it is the responsibility of each traffic system to route messages to suitable gateway stations. Within digital messaging this is achieved with pre-defined routes.

Dedicated target stations may be assigned to take international traffic and put it on the digital system. A target station for your return traffic may be named in an op note following the signature, e.g.

    3456 R DL4FN 8 ERBACH/ODW DEU 1630 DEC 24
    FRITZ KD3QV
    GRANTHAM NH 03753
    =
    UR NR 1234 RCVD DEC
    24 1600 UTC
    =
    PETER DL4FN
    OP NOTE REPLY OR SERVICE
    MESSAGE TO DL4FN VIA KW1U
    CONCORD MA 01742

This instructs handling stations to send return traffic C/O KW1U. A reply message may have this route in either the first address line as we have already seen above or in an op note following the address as in

    NR 1235 R KD3QV 12 GRANTHAM NH 1600 DEC 25
    PETER DL4FN
    CONCORD MA 01742
    OP NOTE ROUTE VIA KW1U MA 01742
    =
    HAPPY TO HEAR THAT MY
    MESSAGE ARRIVED SO QUICKLY
    X KIND REGARDS
    =
    FRITZ KD3QV

Any digital station should know how to handle international traffic. Options to route an international message include: send your message to...

  • ... a known target station with C/O
  • ... a known target station named in an op note
  • ... any (preferably the nearest) digital station for handling.

Message paths may include both manually operated circuits and unattendendly operating digital systems.


Manually handling international traffic

When handling traffic inside your traffic system use the established operating procedures. For a sked with a station in a different traffic system best use the operating procedures defined for the maritime mobile and fixed radio services in the Radio Regulations.

Here is a transcript of a CW sked between WB8WKQ and DF0NTS:

    WB8WKQ: DF0NTS DF0NTS DE WB8WKQ WB8WKQ K
    DF0NTS: WB8WKQ DE DF0NTS = QRK 4 = QTC 1 K
    WB8WKQ: QSA 4 QRV K
    DF0NTS: WB8WKQ DE DF0NTS
            (ka)
            98 R G0DUB 17 CHESTER GBR 2012 SEP 4
            LOUIS SZONDY VK5EEE (aa)
            93 CRITTENDEN ROAD (aa)
            FINDON SA 5023 (aa)
            AUSTRALIA
            =
            ... ... ...
            =
            GREG G0DUB CHESTER GBR (aa)
            OP NOTE REPLY VIA NTSD TO G0DUB ATSIGN NTSEU
            +
            QSL? = WB8WKQ DE DF0NTS K
    WB8WKQ: QSL QRU = GN PETER = DF0NTS DE WB8WKQ (sk)
    DF0NTS: GN JEFF = TKS TKNG TFC = WB8WKQ DE DF0NTS (sk) CL

Only Q signals defined in the Radio Regulations (QOA -- QUZ) are used. Note that QN signals are usually not known outside the US and Canada. Although signal reports are normally given with the RST system both operators prefer Q signals (QRK, QSA) instead.

Particular attention should be payed to the use of telegraphy prosigns. Besides the standard prosigns (ka), =, +, and (sk) we used (aa as the American Morse comma) to separate the address lines. However, this is not widely known internationally and the comma should be used instead.

Furthermore you may encounter a = sign between the preamble and the address part. So be prepared to hear something like:

    (ka)
    98 R G0DUB 17 CHESTER GBR 2012 SEP 4
    =
    LOUIS SZONDY VK5EEE --..--
    93 CRITTENDEN ROAD --..--
    FINDON SA 5023 --..--
    AUSTRALIA
    =
    ... ...


Digital international traffic

Messages addresses in the international digital traffic system are based on the three-letter country codes defined in ISO 3166. Either callsigns (preferred) or zip codes may be used in the TO part of the address and the AT part consists of a dash followed by the country code.

Here are some examples. NOTE THAT THESE ARE FOR INTERNATIONAL MESSAGES AND THAT YOUR LOCAL ADDRESS SCHEME HAS TO BE USED FOR MESSAGES INSIDE YOUR OWN TRAFFIC SYSTEM.

    Postal address          Digital traffic address(es)
    --------------------------------------------------------
    PETER DL4FN              DL4FN @ -DEU
    64711 ERBACH             64711 @ -DEU
    GERMANY

    GREG G0DUB               G0DUB @ -GBR
    CHESTER CH3 7NT         CH37NT @ -GBR
    GREAT BRITAIN

    MARCIA KW1U              01742 @ -USA  (see notes below)
    CONCORD MA 01742
    USA

    GLENN VE3GNA            K0K3G0 @ -CAN  (see notes below)
    TAMWORTH ON K0K 3G0
    CANADA

    LOUIS VK5EEE            VK5EEE @ -AUS
    FINDON SA 5023            5023 @ -AUS
    AUSTRALIA

Remember that the same three-letter country codes are also used in message preambles which makes it relatively easy to determine the digital address of a station:

    3456 R DL4FN 8 ERBACH/ODW DEU 1630 DEC 24
            |                  |
            +------- DL4FN @ -DEU


    98 R G0DUB 17 CHESTER GBR 2012 SEP 4
           |               |
           +---- G0DUB @ -GBR

The old address scheme based on the routing domains @NTSEU (for Europe) and @NTSOC (for Oceania) is still supported.

For international traffic destined to the US and Canada (i.e. originating e.g. in Europe) use the same address scheme with the country codes -CAN for Canada and -USA for the USA. These will be translated to the NTSxy routing designators before entering the US DTN. Thus 01742@-USA will change to 01742@NTSMA before the message enters the US DTN. Note that message routing based on callsigns (e.g. KW1U@-USA) is not supported by the US DTN.

Besides the digital address the subject field has to be filled. For traffic to the US and Canada use the city name, the first two groups of the recipient's phone number (or the words NO PHONE) and the callsign. For messages to other destinations you may leave out the phone part. Thus "ERBACH DL4FN" is sufficient.


Callsign prefixes and country codes

The following table lists callsign prefixes and country codes for popular countries in international traffic. You will find a complete list of country codes in the Wikipedia article on ISO 3166-1 alpha-3.

Country Prefixes Country Code
Australia VI, VK AUS
Austria OE AUT
Belgium ON -- OT BEL
Canada VA -- VE CAN
Czech OK, OL CZE
Fiji 3D FJI
France F, FA -- FF, FV, TM FRA
Germany DA -- DR DEU
Great Britain G, M, 2E GBR
Iceland TF ISL
Ireland EI, EJ IRL
Israel 4X, 4Z ISR
Italy I ITA
Netherlands PA -- PI NLD
New Zealand ZK -- ZM NZL
Portugal CR -- CU PRT
Russia R, U RUS
Slovakia OM SVK
Slovenia S5 SVN
Spain EA -- EH ESP
Sweden SA -- SM, 7S, 8S SWE
Switzerland HB, HE CHE
USA AA -- AL, K, N, W USA


Background on digital traffic routing

The rather unusual dash character at the start of the AT address part has been chosen to indicate international traffic because it does not seem to conflict with any of the existing digital traffic systems. Digital traffic stations and (regional) MBOs may simply route all addresses of the form @-* to central message hubs.

Those central hubs have to decide where to further route international messages. To this end each of the digital traffic systems is assigned a two-letter designator. For the European traffic system this is EU and for a message to DL4FN@-DEU the AT part -DEU is aliased to the virtual routing domain _EU at a central message hub and subsequently forwarded to the gateway MBO responsible to exchange traffic with the European digital traffic system.

Eventually the gateway MBOs know their partner MBOs in the other traffic systems and exchange traffic with them.

Here is the path of a potential message from K6HTN in California to G0DUB in England showing how Digital Traffic Stations, MBOs, and gateway stations play together.

station and role                  msg address     msg route
----------------------------------------------------------------
K6HTN   Digital Traffic Station
    originates a message to       G0DUB@-GBR
    and submits all traffic to
    WS6P                                          *>>WS6P

WS6P    regional MBO
    forwards all international
    traffic (@-*) to W5KAV                        @-*>>W5KAV

W5KAV   central MBO
    aliases -GBR to the virtual
    routing domain _EU and
    forwards all @_EU traffic
    to KW1U                                       @_EU>>KW1U

KW1U    gateway to Europe
    forwards all messages for
    @_EU to DB0NTS (using the
    same alias list as W5KAV)                     @_EU>>DB0NTS

DB0NTS  gateway to US
    assigns the message to GBR
    DTS                                           @-GBR>>G4KUJ

G4KUJ   Digital Traffic Station
    retrieves the message to      G0DUB@-GBR
    and delivers it to the
    recipient

For a return message the translation to the local US address scheme NTSxy is performed at the European gateway station DB0NTS:

station and role                  msg address     msg route
----------------------------------------------------------------
G4KUJ   Digital Traffic Station
    originates a message for
    KK6AHZ addressed to           92345@-USA
    and submits it to DB0NTS                      @-USA>>DB0NTS

DB0NTS  gateway to US
    rewrites this to the
    appropriate US DTN routing
    domain                        92345@NTSCA
    and queues it for KW1U                        @NTS*>>KW1U

KW1U    gateway to Europe
    receives the message and
    forwards it to W5KAV                          @NTSCA>>W5KAV

W5KAV   central MBO                               @NTSCA>>WS6P
    forwards the message to
    the regional MBO WS6P

WS6P    regional MBO
    assigns the message to
    the K6HTN DTS                                 92*>>K6HTN

K6HTN   Digital Traffic Station
    retrieves the message to      92345@NTSCA
    and delivers it to the
    recipient

From the user perspective message addressing is based on three-letter country codes and never changes. However, the two-letter designators for the individual traffic systems allow for easy changes in the background and for rather simple traffic routes. Additionally changes in message routing do not effect all MBOs in a traffic system.

Useful links

Conceptual Documents

Operational Documents