Status-Acknowledge(Ack)

The Status-Acknowledge(Ack) message flows from the node to the application and from the application to the node, and is used with both SSCP and PLU connections.

The following structure shows the message format for all SSCP messages and for PLU messages flowing from the node to the application.

struct Status-Acknowledge(Ack) {
    PTRBFHDR  nxtqptr;
    PTRBFELT  hdreptr;
    CHAR      numelts;
    CHAR      msgtype;
    CHAR      srcl;
    CHAR      srcp;
    INTEGER   srci;
    CHAR      destl;
    CHAR      destp;
    INTEGER   desti;
    CHAR      sfhdr.stackhdr.akstat;
    CHAR      sfhdr.stackhdr.akqual;
    INTEGER   sfhdr.stackhdr.akmsgkey;
    CHAR      sfhdr.stackhdr.akflags1;
    CHAR      sfhdr.stackhdr.akflags2;
    INTEGER   sfhdr.stackhdr.aknumb1;
    INTEGER   sfhdr.stackhdr.aknumb2;
    INTEGER   sfhdr.stackhdr.akseqno;
}; 
 

LUA only (see Remarks):
Element

struct Status-Acknowledge(Ack) {
    PTRBFELT   hdreptr->elteptr;
    INTEGER    hdreptr->startd;
    INTEGER    hdreptr->endd;
    CHAR       hdreptr->trpad;
    CHAR[268]  hdreptr->dataru;
}; 
 

Members

nxtqptr
Pointer to next buffer header.
hdreptr
Pointer to buffer element (NIL if not using LUA).
numelts
Number of buffer elements (0x00 if not using LUA).
msgtype
Message type STATFMI (0x21).
srcl
Source locality.
srcp
Source partner.
srci
Source index.
destl
Destination locality.
destp
Destination partner.
desti
Destination index.
sfhdr.stackhdr.akstat
Status type ACK (0x01).
sfhdr.stackhdr.akqual
Acknowledgment type ACKPOS (0x02).
sfhdr.stackhdr.akmsgkey
Message key.
sfhdr.stackhdr.akflags1
Application flag 1.
sfhdr.stackhdr.akflags2
Application flag 2.
sfhdr.stackhdr.aknumb1
Undefined.
sfhdr.stackhdr.aknumb2
Reserved.
sfhdr.stackhdr.akseqno
SNA sequence number.

LUA only (see Remarks):
Element

hdreptr–>elteptr
Pointer to buffer element (NIL).
hdreptr–>startd
Start of data in this buffer element

13 or
10 for second and subsequent segments of outbound segmented RUs

hdreptr–>endd
End of data in this buffer element.
hdreptr–>trpad
Reserved.
hdreptr–>dataru
Data RU.

The message format for PLU messages flowing from the application to the node is identical to the preceding format, except that the application flag 1 and application flag 2 fields are not used. They are replaced by the following INTEGER field:

sfhdr.stackhdr.akmsgtim
Last host response time

0xFFFF - no response time measured
0xnnnn - last response time measured, in units of 0.1 second

Remarks