MTPBK Back to Index page
Control Block Contents 
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.

  MTPBK Prolog Top of page
              This copy file contains:
              MTPBK DSECT which maps a Member Topology Packet (MTP)
              MTRTABLE MACRO that is used to define the synchronization
              request router table
              MTRTABL DSECT which maps a router table entry
 FUNCTION   : Used to transmit Relocation Domain topology to other members
              of the SSI. The MTPBK is used in four circumstances:
              1) To propagate a DEFINE DOMAIN request from the member that
              receives the user's command to other members of the SSI.
              2) To propagate notification of a concurrent upgrade to
              members of the SSI.
              3) For resynchronization purposes when a member rejoins the
              SSI following a transition out of safe mode.
              4) For synchronization purposes when a member first joins the
              SSI cluster.
              Each of these four uses requires different processing on the
              receiving system. Therefore a router worker ID is included in
              the MTP to allow the receiving thread to route the MTP
              Router table entries comprise the worker routine address
              with a flag to indicate whether they are invoked synchronously
              or asynchronously using a deferred call.
              Synchronous calls return an MTP from the receive in the
              SEND_REPLY message.
              Asynchronous calls return a SEND_REPLY VOTE=YES as soon as
              the worker has been scheduled.  No MTP response is sent back.
              The worker routines are responsible for freeing their input
 LOCATED BY : In the message buffer portion of an MBHBK
 DELETED BY : Synchronization worker routines once they are
              finished their work.
 SERIALIZED : The VAAXLK will be held during processing that uses MTPBKs.
  MTPBK Control Block Content Top of page

 MTPBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure MTPBK MEMBER TOPOLOGY PACKET 0000 0 Signed 4 MTPLEN Length of MTPBK in bytes 0004 4 Signed 4 MTPSNDX Sending member's index 0008 8 Signed 4 MTPCVN Comms Version for domain sync operations MTPCVN is used to identify the communications protocol version used by cross-SSI Domain and ARD synchronization. The VAACVN is stored in the Member Topology Packet in MTPCVN to alert a remote member of the version of the comms structures and protocols in use by the CP. When a MTPBK is created MTPCVN is populated with MTPCVER. 00000001 MTPCV1 1 Comms Version 1 00000002 MTPCV2 2 Comms Version 2 00000003 MTPCV3 3 Comms Version 3 00000004 MTPCV4 4 Comms Version 4 00000005 MTPCV5 5 Comms Version 5 00000006 MTPCV6 6 Comms Version 6 00000007 MTPCV7 7 Comms Version 7 00000008 MTPCV8 8 Comms Version 8 00000009 MTPCV9 9 Comms Version 9 00000001 MTPCVER MTPCV1 Comms Version supported by this CP 000C 12 Signed 4 MTPRID Router Worker Id (or Request ID) 0010 16 Signed 4 MTPSEQ State sequence number for this request. For synchronization requets this will be set to the sender's VAASEQ. For new DEF RELO requets this will be set to the sender's next state (VAASEQN) 0014 20 Signed 4 MTPDCT Number of Domain Entries in Packet 0018 24 Bitstring 1 MTPFLAGS Flags for the message 1... .... MTPGLOCK X'80' MTPGLOCK Indicates that the requester has acquired the VAAXLK lock globally. If this bit is OFF, the receiver(s) of this packet must get the lock locally before doing the necessary processing. If it is ON, the receiver must call HCPXLKUU to inform the lock manager it will release the lock. 0019 25 Bitstring 3 * Reserved for future IBM use 001C 28 Signed 4 MTPXLUNQ Value of XLKUNQ after the global lock was obtained. This is passed to the remote system which then passes it to HCPXLKUU to register that the remote worker routine is now responsible for releasing the lock on that system 00000020 MTPHLEN *-MTPBK MTP Header length The rest of the MTPBK is variable length depending on the number of domains in the member's topology. There is one MTPENT for each domain in the member's topology. They are appended here as an array of MTPENTs one after the other. MTPDCT contains the count of entries appended in the packet. 0020 32 Bitstring 12 MTPENT Domain Entry 0020 32 Character 8 MTPDNM Domain Name 0028 40 Bitstring 4 MTPDMM Domain Membership Mask. Zero mask signals domain deletion. 0000000C MTPENTL L'MTPENT Length of a domain entry (bytes) 00000004 MTPHDDWL (MTPHLEN+7)/8 Length of an MTP header (DWs) Mapping DSECT for the MTP Router Table
  MTPBK Storage Layout Top of page
*     +---------------------------+---------------------------+
*   0 |          MTPLEN           |         MTPSNDX           |
*     +---------------------------+---------------------------+
*   8 |          MTPCVN           |          MTPRID           |
*     +---------------------------+---------------------------+
*  10 |          MTPSEQ           |          MTPDCT           |
*     +------+--------------------+---------------------------+
*  18 |:FLAGS|////////////////////|         MTPXLUNQ          |
*     +------+--------------------+---------------------------+
*  20 |                        MTPENT                         |
*     |                           +---------------------------+
*     |                           | 2C
*     +---------------------------+
*** Overlay for MTPENT in MTPBK
*     +-------------------------------------------------------+
*  20 |                        MTPDNM                         |
*     +---------------------------+---------------------------+
*  28 |          MTPDMM           | 2C
*     +---------------------------+
*** Overlay for MTPENT in MTPBK
  MTPBK Cross Reference Top of page
Symbol         Dspl Value
-------------- ---- -----
MTPCVER        0008 00000001
MTPCVN         0008
MTPCV1         0008 00000001
MTPCV2         0008 00000002
MTPCV3         0008 00000003
MTPCV4         0008 00000004
MTPCV5         0008 00000005
MTPCV6         0008 00000006
MTPCV7         0008 00000007
MTPCV8         0008 00000008
MTPCV9         0008 00000009
MTPDCT         0014
MTPDMM         0028
MTPDNM         0020
MTPENT         0020
MTPENTL        0028 0000000C
MTPFLAGS       0018
MTPGLOCK       0018 80
MTPHDDWL       0028 00000004
MTPHLEN        001C 00000020
MTPLEN         0000
MTPRID         000C
MTPSEQ         0010
MTPSNDX        0004
MTPXLUNQ       001C
This information is based on z/VM 6.3.0 Last updated on 22 May 2013 at 13:55:00 EDT.
Copyright IBM Corporation, 1990, 2013