TRANSFER Programming Manual

P1 Messages—General Message Handling
X400 Services
6–4 069138, Update 1 to 040970 Tandem Computers Incorporated
Mail service elements include a wide range of mail features that can be used for X.400
or TRANSFER messages. For example, you can request the following services:
Receipt notification—notify the originator when a recipient reads a message.
Sensitivity—assign a relative security to the message. Values include personal,
private, company-confidential, and default (no security).
Blind copy—do not display selected recipient names to primary and courtesy copy
recipients.
Your TRANSFER client performs a portion of the work of the X.400 mail service when
you specify recipients, add message contents, and request service elements. The
TRANSFER delivery system and the X400 Gateway perform the remainder of the mail
service work.
P1 Messages—
General Message Handling
The MTL uses a protocol called P1 to format and route X.400 messages. P1 service
elements (delivery features) can be requested for all X.400 messages.
A P1 message consists of an envelope and its content. The envelope contains delivery
information including recipient names and addresses, priority, delivery notification
requirements, and other information. The content is the actual information to be
transmitted, such as a P2 mail message or a report.
The combination of an envelope and its content is functionally equivalent to a
TRANSFER package.
Figure 6-3 illustrates the format of a P1 message.
Figure 6-3. A P1 Message
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Envelope
Content
When you submit an X400 mail message, the UAL generates the P2 protocol and
submits the P2 message to the MTL, which in turn embeds the P2 message into the
content portion of a P1 message. The MTL then forwards the message to the X400
network.