(Page 12 of 14 in this chapter) Version

Status Request

Direction

Layer 3 -> MTP 2

Description

The STATUS REQUEST is used to request one of a number of special functions supported by the MTP 2 layer. They are:

MTP 2 returns a STATUS CONFIRM message containing the current BSN (last acknowledged sequence number) for a link to the application in response to a "retrieve BSN" status request. MTP 2 may also return a STATUS CONFIRM message in response to a "retrieve messages" status request, but only if there are no unacknowledged messages to be retrieved. If there are unacknowledged messages to be retrieved, a DATA CONFIRM indicating a status of "unacknowledged [more | last]" is sent to the application for each message (the last indicates that it is the last). In this case, no STATUS CONFIRM is returned to the application.

Format

Service Provider ID MTP 2's reference number for this link on this TX board. Must be 0-15.

Action The action to take. Possible values are:

 
   0  No Action; indicate change in status
      to MTP 2 as specified in status field
   1  Retrieve backward sequence number
   2  Retrieve unacknowledged messages
   3  Drop all queued transmit messages
Status The status change being indicated to MTP 2, when Action = 0. Possible values are:

   
   0  Local processor is down
   1  Local processor is up
   2  Emergency condition
   3  Emergency ceases
when Action = 2; only possible value is the starting sequence number, usually retrieved from an MTP3 COO or COA, to retrieve unacknowledged messages from the board


(Page 12 of 14 in this chapter) Version

tech_support@nmss.com
Copyright © 2000, Natural MicroSystems, Inc. All rights reserved.