The potential for heavy snow at higher elevations in the western U.S. will continue for many spots through the weekend. In the meantime, the eastern half of the continental U.S. will transition to above normal temperatures ahead of a pair of cold fronts next week that will bring readings back to closer to normal as we approach Thanksgiving Day. Read More >
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
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
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
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.
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).
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
Format for the request:
Note: limit restriction - no more than eight headings in a request
Examples - CLASS 2
Where: AMMC is the center the message is addressed to; and, KWBC is the originating center of the message
Where: KWBC is the center the message is addressed to; and, AMMC is the originating center of the message
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).
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:
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.
Where: KWBC is the center the message is addressed to; and, AMMC is the originating center of the message
Where: KWBC is the center the message is addressed to; and, AMMC is the originating center of the message
Where: KWBC is the center the message is addressed to and, AMMC is the originating center of the message
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
