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Periods of Snow in the Northern Rockies and Great Lakes

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FORMAT FOR THE TEXT OF ADDRESSED MESSAGES

ATTACHMENT II-6

AND A GENERAL EXAMPLE OF EACH TYPE

GENERAL FORMAT FORM
(only alphabet 5 is shown)

The abbreviated heading format for addressed messages consists of two lines of information. It is important to note that this bulletin is constructed where the first line tells the routing tables of the GTS where the message is to be sent.

The form of the abbreviated heading:

T1 T2 A1 A2 ii   CaCaCaCa   YYGGgg
CCCC

where,

T1T2 =
  BM designator for message in alphanumeric form
  BI designator for addressed message in binary form (use on X.25 links only)

A1A2 = type of addressed message

    options:
   AA - administrative message (to be passed to a person for information or action)
   BB - service message (to be passed to a person for action)
   RR - request for a GTS message by heading or sequence number
   RQ - request-to-database for data (request format TBD) intended for GDPS action
   DA - the returned data response to the RR or RQ addressed message

ii = always 01 (no exceptions allowed)

CaCaCaCa = location indicator of the center on the GTS
to whom the message is addressed

YYGGgg = time of insertion on the GTS

CCCC = the international location indicator of the center originating the message


TYPE 1

A1 A2 = AA - Administrative message

The contents of this type message is a simple character free flowing text, intended for human readability. This message type should be sent to a computer display or a printer. This type text message should be about general operational and/or administrative matters or discussions and GTS coordination topics. The T1 T2 option to use is BM only, as the text is character data.

Example:

345
BMAA01 EDZW 261215
EGRR ATTN OFFENBACH DATA MANAGER
THE BULLETINS YOU REQUESTED WILL BE RELAY TO YOUR CENTER
BEGINNING THE FIRST OF THE MONTH
SMVG01 TVSV
SMTD01 TTPP
REGARDS, BMO DATA MANAGER SUPERVISOR=

Note: EDZW is the center the message is addressed to; EGRR is the originating center of the message


TYPE 2

A1A2 = BB - Service message

The contents of this type message is a simple character free flowing text, intended for human readability. These message types should be sent to a display or printer. These are text messages about operational status and/or problem resolution matters. The T1 T2 option to use is BM only, as the text is character data.

Example:

321
BMBB01 EGRR 281425
KWBC
ATTN BRACKNELL COMMUNICATIONS SUPERVISOR
THE GTS LINK BETWEEN WASHINGTON AND BRASILIA IS DOWN FOR
6 HOURS DUE TO LINE RECONFIGURATION AT BRASILIA.
REGARDS, WASHINGTON COMMS SUPERVISOR=

Note: EGRR is the center the message is addressed to; KWBC is the originating center of the message


TYPE 3

A1A2 = RR - Request/Reply message

The structure of the text for this type message has two specific classes using two different formats in the request text. This addressed message type is for use between nodes of the GTS. To use the CLASS 1 formatted request form, the nodes of the GTS must be adjacent nodes. To use the CLASS 2 formatted request form, the nodes of the GTS do not have to be adjacent to each other. The request / reply type message is for the acquisition of data at the bulletin level and the bulletin is assumed to already exist. If it is sent on an X.25 virtual channel established for the exchange of alphanumeric data, then the T1 T2 option of BM is recommended; and if, the X.25 virtual channel was established for binary data exchange, then the T1 T2 option of BI is recommended. If there is only one virtual channel between nodes for both alphanumeric and binary data exchange, it is recommended to use the T1 T2 option of BI as a default. The use of the T1 T2 option of BM would be used on all GTS links using character protocols (i.e. BAUDOT or ERROR CONTROL PROCEDURES), as all addressed messages and request / reply responses are alphanumeric.


  • CLASS 1. Request for Repetition - to be sent between adjacent centers only. There can be three choices in the text of the request. The choices are:
    1. for requesting only one message by its transmission sequence number,
    2. for requesting a range of consecutive transmission sequence numbers, or
    3. for requesting a group of specific messages by their transmission sequence numbers.

    There will be only one request line per message.

    The response to the request/reply CLASS 1 message will consist of two parts. The first part will be the construction and transmission of a status message using the TYPE 5 - data message format, indicating that action has been taken. This will be called a status of action message. The second part will be the transmission of the requested message(s). This will be a repeat of the originally sent message, including the original sequence number(s). The resulting transmission will most likely put the on going sequence numbers out of order. This should confirm, for the requesting center, the receipt of the needed message(s).

    • Choice 1 - Requesting only one (previously received) message
      1. Format for and alphanumeric virtual channel or for any non-X.25 GTS link.

        (SOH)(CR)(CR)(LF) nnn

        (CR)(CR)(LF) BMRR01 CaCaCaCa YYGGgg

        (CR)(CR)(LF) CCCC

        (CR)(CR)(LF) SQN nnn =                       [one bulletin]

        (CR)(CR)(LF)(ETX)
         
      2. Format for and binary virtual channel on X.25 GTS links.

        (SOH)(CR)(CR)(LF) nnn

        (CR)(CR)(LF) BIRR01 CaCaCaCa YYGGgg

        (CR)(CR)(LF) CCCC

        (CR)(CR)(LF) SQN nnn =                        [one bulletin]

        (CR)(CR)(LF)(ETX)
         
    • Choice 2 - Requesting a continuous series of (previously received) messages
      1. Format for an alphanumeric virtual channel or for any non-X.25 link.

        (SOH)(CR)(CR)(LF) nnn

        (CR)(CR)(LF) BMRR01 CaCaCaCa YYGGgg

        (CR)(CR)(LF) CCCC

        (CR)(CR)(LF) SQN nnn-nnn =                       [a sequence of bulletins]

        (CR)(CR)(LF)(ETX)
         
      2. Format for and binary virtual channel on X.25 GTS links.

        (SOH)(CR)(CR)(LF) nnn

        (CR)(CR)(LF) BIRR01 CaCaCaCa YYGGgg

        (CR)(CR)(LF) CCCC

        (CR)(CR)(LF) SQN nnn-nnn =                       [a sequence of bulletins]

        (CR)(CR)(LF)(ETX)
         
    • Choice 3 - Requesting specific (previously received) messages
      1. Format for an alphanumeric virtual channel or for any non-X.25 link.

        (SOH)(CR)(CR)(LF) nnn

        (CR)(CR)(LF) BMRR01 CaCaCaCa YYGGgg

        (CR)(CR)(LF) CCCC

        (CR)(CR)(LF) SQN nnn/nnn/nnn =                       [a selected number of bulletins]

        (CR)(CR)(LF)(ETX)
         
      2. Format for and binary virtual channel on X.25 GTS links.

        (SOH)(CR)(CR)(LF) nnn

        (CR)(CR)(LF) BIRR01 CaCaCaCa YYGGgg

        (CR)(CR)(LF) CCCC

        (CR)(CR)(LF) SQN nnn/nnn/nnn =                       [a selected number of bulletins]

        (CR)(CR)(LF)(ETX)
         

      Note: limit restriction - only one SQN line in a request

    Example - CLASS 1

    788
    BMRR01 LFPW 301215
    DAMM
    SQN 212-217=

    Where: LFPW is the center the message is addressed to; and, DAMM is the originating center of the message


  • CLASS 2. Request for a bulletin - can be sent to any center on the GTS. There is only one choice for the form of the text of the request. The form is always alphanumeric, however, the T1 T2 option of BM is to be used for all requests for alphanumeric messages, and the T1 T2 option of BI is to be used for all requests for binary messages, as all returned responses will use the same T1 T2 for the heading type to facilitate proper routing when X.25 or equivalent links are required.

    Format for the request:

    • Requests for messages (alphanumeric message request)

      (SOH)(CR)(CR)(LF) nnn

      (CR)(CR)(LF) BMRR01 CaCaCaCa YYGGgg

      (CR)(CR)(LF) CCCC

      (CR)(CR)(LF) AHD T1T2A1A2ii CCCC YYGGgg =

      (CR)(CR)(LF) AHD T1T2A1A2ii CCCC YYGGgg BBB =

      (CR)(CR)(LF)(ETX)
       

      Note: limit restriction - no more than eight headings in a request

    Examples - CLASS 2

    • Used for a non-binary X.25 virtual channel

      051
      BMRR01 AMMC 081220
      KWBC
      AHD SNAU55 AMMC 081100 RRA=
      AHD SMID20 WIIX 081200=

      Where: AMMC is the center the message is addressed to; and, KWBC is the originating center of the message

    • Used for a binary X.25 virtual channel only

      110
      BIRR01 KWBC 081220
      AMMC
      AHD HTAC30 KWBC 081200 =
      AHD HHBC85 KWBC 081200 =

      Where: KWBC is the center the message is addressed to; and, AMMC is the originating center of the message


TYPE 4

A1 A2 = RQ - Request-to-Database message

The format for this type message will be in a specific format. The intent is for automatic computer processing. There is one type of request message to a data base (for GDPS use).

  • Format for the request:

    (SOH)(CR)(CR)(LF) nnn

    (CR)(CR)(LF) BIRQ01 CaCaCaCa YYGGgg

    (CR)(CR)(LF) CCCC

    (CR)(CR)(LF) [TBD]                       [WG/DM will define]

    (CR)(CR)(LF)(ETX)
     

TYPE 5

A1A2 = DA Data message

This is the returned data message type. The purpose of this heading is to insure that if the requested data message is a bulletin containing a WMO abbreviated heading, the heading of the requested message heading is not used in the routing of the response back to the requesting center. To insure proper routing the T1 T2 for either BM or BI must reflect the code type in the returning data message. The data message has four different response forms. The response can be:

  1. the requested message,
  2. message not found,
  3. message heading not recognized, or
  4. status message of action taken on RR CLASS 1 request.

There is only one bulletin or meta-data-file in a responding data message. In the examples below, assume the data massage can either be BM or BI for the CLASS 1 depending on which virtual channel. If both the alphanumeric and binary messages are transmitted on only one virtual channel the use of BI will be the default.

  • Example of a requested message:

    543
    BMDA01 KWBC 081550
    AMMC
    SIID20 WIIX 081500
    AAXX 08151
    58424 42975 02203 10297 20251 40037 52008=

    Where: KWBC is the center the message is addressed to; and, AMMC is the originating center of the message

  • Example of the message not found (NIL response):

    189
    BMDA01 KWBC 081250
    AMMC
    NIL SNAU55 AMMC 081100 RRB=
     

    Where: KWBC is the center the message is addressed to; and, AMMC is the originating center of the message

  • Example of the message not recognized (ERR response):

    154
    BMDA01 KWBC 081250
    AMMC
    ERR SIID20 WIIX 081200=

    Where: KWBC is the center the message is addressed to and, AMMC is the originating center of the message

  • Example of the reply message to the RR type CLASS 1 request (STATUS response):

    264
    BMDA01 RJTD 101255
    KWBC
    RETRANSMISSION ACTIVATED FOR 212-218=

    Where: RJTD is the center the message is addressed to; and, KWBC is the adjacent originating center of the message.

Note: limitation - circuits or virtual channels with priority queues must guard against confusion when selecting and responding to sequence number requests for transmission.

WHERE: (CR) = Carriage Return
                (LF) = Line Feed
                (SOH) = Start of header control character
                (ETX) = End of text control character