X400: How MS-DOS and Windows Priorities Convert to X.400

The information in this article applies to:

• Microsoft Mail Gateway to X.400, version 3.2

SUMMARY

This article explains how priorities chosen in the MS-DOS and Windows client are converted to those within X.400 messages. The behavior is the same for both selectable X.400 profiles (NIST and A311).

MORE INFORMATION

The most commonly used priority setting fields in X.400 are the P1 UMPDU Envelope Priority and the P2 IM-UAPDU Heading Importance field. These fields are generated by MS-DOS client priorities 1 and 5, and by Windows client priorities low and high. Priorities 2 through 4 (for the MS-DOS client), or normal (for the Windows client) do not generate the Priority or Importance fields.

The Priority field (part of the P1 UMPDU Envelope) affects the delivery time of the message within the X.400 system. MTAs favor high priority to lower ones when forwarding messages to the next MTA.

The Priority field can have these values:

   0 (normal)
   1 (non urgent)
   2 (urgent)

The Importance field can have these values:

   0 (low)
   1 (normal)
   2 (high)

MS-DOS client   P1 Priority field     P2 Importance field
-------------   -----------------     -------------------
   1            1 (non urgent)          0 (low)
   2            - (not generated)      - (not generated)
   3            - (not generated)      - (not generated)
   4            - (not generated)      - (not generated)
   5            2 (urgent)             2 (high)

WIN client   P1 Priority field     P2 Importance field
----------   -----------------     -------------------
low          1 (non urgent)          0 (low)
normal       - (not generated)       - (not generated)
high         2 (urgent)              2 (high)