RFC3018 - Unified Memory Space Protocol Specification

Network Working Group A. Bogdanov
Request for Comments: 3018 NKO "ORS"
Category: EXPerimental December 2000
Unified Memory Space Protocol Specification
Status of this Memo
This memo defines an Experimental Protocol for the Internet
community. It does not specify an Internet standard of any kind.
Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
This document specifies Unified Memory Space Protocol (UMSP), which
gives a capability of immediate Access to memory of the remote nodes.
Conventions used in this document
The key Words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [2].
The following syntax specification uses the augmented Backus-Naur
Form (ABNF) as described in RFC-2234 [3].
Table of Contents
1. IntrodUCtion...................................................4
2. The UMSP Model.................................................5
2.1 128-bit Address Space.......................................5
2.2 Computing Model.............................................7
2.3 System Architecture.........................................9
3. Instruction Format............................................11
3.1 Instruction Header.........................................12
3.2 Extension Headers..........................................15
3.3 Instruction Operands.......................................17
3.4 Address Formats............................................17
4. Response of the Instructions..................................19
4.1 RSP, RSP_P.................................................20
4.2 SND_CANCEL.................................................20
5. Jobs Management...............................................21
5.1 Job Initiate...............................................23
5.1.1 CONTROL_REQ............................................24
5.1.2 CONTROL_CONFIRM........................................25
5.1.3 CONTROL_REJECT.........................................26
5.2 Task Initiate..............................................26
5.2.1 TASK_REG...............................................26
5.2.2 TASK_CONFIRM...........................................27
5.2.3 TASK_REJECT............................................28
5.2.4 TASK_CHK...............................................28
5.3 Establishment of session connection........................29
5.3.1 SESSION_OPEN...........................................29
5.3.2 SESSION_ACCEPT.........................................31
5.3.3 SESSION_REJECT.........................................31
5.3.4 Connection Profile.....................................32
5.4 Session Closing............................................33
5.4.1 SESSION_CLOSE..........................................34
5.4.2 SESSION_ABEND..........................................35
5.5 Task Termination...........................................35
5.5.1 TASK_TERMINATE.........................................36
5.5.2 TASK_TERMINATE_INFO....................................36
5.6 Job Completion.............................................37
5.6.1 JOB_COMPLETED..........................................37
5.6.2 JOB_COMPLETED_INFO.....................................38
5.7 Activity Control of Nodes..................................38
5.7.1 _INACTION_TIME.........................................39
5.7.2 STATE_REQ..............................................40
5.7.3 TASK_STATE.............................................41
5.7.4 NODE_RELOAD............................................42
5.8 Work without session connection............................42
6. Instructions of Exchange between VM...........................44
6.1 Data Reading/Writing Instructions..........................45
6.1.1 REQ_DATA...............................................45
6.1.2 DATA...................................................46
6.1.3 WRITE..................................................46
6.1.4 WRITE_EXT..............................................47
6.2 Comparison Instructions....................................47
6.2.1 CMP....................................................47
6.2.2 CMP_EXT................................................48
6.2.3 Response to Comparison Instructions....................48
6.3 Control Transfer Instructions..............................48
6.3.1 JUMP, CALL.............................................48
6.3.2 RETURN.................................................49
6.4 Memory Control Instructions................................50
6.4.1 MEM_ALLOC..............................................50
6.4.2 MVCODE.................................................50
6.4.3 ADDRESS................................................51
6.4.4 FREE...................................................51
6.4.5 MVRUN..................................................51
6.5 Other Instructions.........................................52
6.5.1 SYN....................................................52
6.5.2 NOP....................................................53
6.6 Work with Objects..........................................53
6.6.1 Reading/Writing of the Objects Data....................54
6.6.1.1 OBJ_REQ_DATA.......................................54
6.6.1.2 OBJ_WRITE..........................................55
6.6.1.3 OBJ_WRITE_EXT......................................56
6.6.2 Comparison Instructions of the Objects Data............56
6.6.2.1 OBJ_DATA_CMP.......................................56
6.6.2.2 OBJ_DATA_CMP_EXT...................................57
6.6.3 Execution of the Objects Procedures....................57
6.6.3.1 CALL_BNUM..........................................57
6.6.3.2 CALL_BNAME.........................................58
6.6.3.3 GET_NUM_PROC.......................................59
6.6.3.4 PROC_NUM...........................................59
6.6.4 The Objects Creation...................................59
6.6.4.1 NEW, SYS_NEW.......................................60
6.6.4.2 OBJECT.............................................61
6.6.4.3 DELETE.............................................61
6.6.5 The Objects Identification.............................61
6.6.5.1 OBJ_SEEK...........................................62
6.6.5.2 OBJ_GET_NAME.......................................62
7. Chains........................................................62
7.1 Sequence...................................................63
7.2 Transaction................................................64
7.2.1 _BEGIN_TR..............................................64
7.2.2 EXEC_TR................................................65
7.2.3 CANCEL_TR..............................................66
7.3 Fragmented instruction.....................................66
7.4 Buffering..................................................67
7.5 Acknowledgement of chains..................................69
7.6 Base-displacement Addressing...............................70
8. Extension Headers.............................................71
8.1 _ALIGNMENT.................................................71
8.2 _MSG.......................................................71
8.3 _NAME......................................................72
8.4 _DATA......................................................72
8.5 _LIFE_TIME.................................................72
9. Search of resources...........................................73
9.1 VM_REQ.....................................................75
9.2 VM_NOTIF...................................................75
10. Security Consideration.......................................77
11. Used Abbreviations...........................................78
12. References...................................................79
13. Author"s Address.............................................80
14. Full Copyright Statement.....................................81
1 Introduction
UMSP is the network connection-oriented protocol. It corresponds to
session and presentation layers of model OSI. The protocol is
designed for implementation in a wide class of systems, from simple
devices based on the dedicated processors, up to universal computers
and clusters.
For the data exchange, the protocol uses transport layer service with
reliable delivery. It is possible to use not providing reliable
delivery protocol for the transmission of not requiring
acknowledgement data. This document describes use TCP and UDP.
The creation of network environment for the organization 128-bit
address space of memory distributed between Internet nodes is the
basic purpose of the protocol UMSP. The protocol defines algorithm
of the connections management and format of network primitives. It
doesn"t control local memory on the node.
As against the traditional network protocols, the user applications
on different nodes interact not by the network primitives exchanging
or working with the dataflows, but by immediate data reading/write or
control transfers to the code in virtual memory of the remote node.
The user"s application can know nothing about existence of the
protocol and network, and simply use the instructions with 128-bit
addresses.
Firstly, it is supposed to use UMSP in systems based on the virtual
machines (VM), executing the pseudo-code. However, the protocol may
be used in systems executing a processor code, for example, in
clusters or in universal operational systems, for the organization of
the distributed virtual address space. Besides, the minimal profile
of the protocol may be used in simple devices, which do not have the
operational system.
The protocol gives various means for set the connection parameters
and allows building systems with a high protection level without
restriction applications functionalities.
UMSP can essentially simplify the distributed systems development
process. It gives an opportunity to unite not only information, but
also calculating resources of the large number of polytypic computers
without significant expenses for the programs standardization and
development.
2 The UMSP Model
2.1 128-bit Address Space
UMSP is based on the 128-bit distributed address memory space model.
The 128-bit address contains the information about the network type,
network node address and local memory address. It has the following
format:
Octets
0 1 16
+------+--------------+--------------------+----------------+
Header FREE NODE_ADDR MEM_ADDR
+------+--------------+--------------------+----------------+
Complete address length is fixed and is equal to 16 octets.
Header
1 octet. Address header field completely defines the address
format. The header has the following format:
Bits
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
ADDR_LENGTH NET_TYPE ADDR_CODE
+-----+-----+-----+-----+-----+-----+-----+-----+
ADDR_LENGTH
4 bits. The length of the network address. This field
contains the number of octets in the NODE_ADDR field. The
value 0 is not allowed.
NET_TYPE
2 bits. The network type. This field specifies a type of
network, in which the node is.
ADDR_CODE
2 bits. The length code of the local memory address. The
value of this field specifies the length of the local memory
address. The following values of the field and appropriated to
them length of the field MEM_ADDR are defined:
%b00 - 16 bit
%b01 - 24 bit
%b10 - 32 bit
%b11 - 64 bit
The values combination of the three fields of heading is named
address format number. These fields unequivocally define a
network, in which the node is located. Format number writes as
follows:
N <ADDR_LENGTH> - <NET_TYPE> - <ADDR_CODE>
For example, N 4-0-2 defines the address with length of the node
network address 4 octets and memory address with the length 32
bits. The network type 0 for such address format is defined for
the network IPv4 in the presented document. If the network type
is equal to zero, it may be missed during the writing of the
address format number. For example, format N 4-0-2 and 4-2 are
equivalent. If both fields NET_TYPE and ADDR_CODE are set to
zero, they may be omitted. Thus, a format number writes as one
figure.
One or several address format numbers must be assigned for each
global network, included in unified system.
FREE
0 - 12 octets. This field is unused by the protocol. It may
contain any additional information, which is necessary for the
control system of the node memory. If this field is not used, the
zero value must be set in all octets. Using of this field results
that the network instructions must contain only complete 16 -
octet address and the short address of local memory cannot be
used.
NODE_ADDR
1 - 13 octets. The node address. The format of this field is
defined separately for each address format number. The field of
the node address should not necessary precisely correspond to the
real network address. If the real network address is longer than
this field, it is necessary to organize in the network a subset of
supporting the protocol UMSP addresses.
MEM_ADDR
16/24/32/64 bits. The address of local memory. This field is the
memory address in system, which is set by a field NODE_ADDR. The
node completely responds for its memory control. The protocol
does not define the order of using and format of this field.
128-bit address for the user applications is one field. The user
code cannot know about a physical arrangement of addressed memory.
The 128-bit memory address may be transmits between nodes, as the
data, for example, in the buffer of function parameters, or in the
instruction of copying the data. Therefore, it must identify the
given node from any other nodes unequivocal.
Any certain algorithm, connecting real network and 128-bit address,
does not exist. All used address formats must be known beforehand.
As UMSP has its own address space, it can unite several global
networks. The nodes can have internal local networks or subordinated
addressable devices connected with the node by the not-network
communications. Any node by address format number must have an
opportunity to define the gateway respond for routing of this
address.
2.2 Computing Model
Computing model is three-layer:
(1) Job
(2) Task
(3) Thread of control
The job corresponds to the user application. The job is distributed
and can simultaneously be executed on many nodes. The job control is
carried out centralize, from the node named as Job Control Point
(JCP). One JCP can control the some jobs. JCP can be located on the
same node, on which the job is created, or on any other addressed net
point.
The task is the job presentation on the separate node. The task
includes one or several computing threads of control. The job has
only one task on each node.
The job is finished, when the appropriate user application is
finished. At the end of the job all tasks of this job on all nodes
are finished.
The job has its isolated 128-bit address space. The address space is
segmented. A segment is the local memory of one node. Besides, the
protocol allows working with objects. The objects are separate
associative memory of the node.
The task thread represents the concrete control thread, which are
executed by VM in the certain node. The thread can read and write to
any address of 128-bit address space of the job. The control
transfer to the address from other (remote) node, results to the
creation of the new thread on the remote node. The continuous code
segment cannot be distributed on several nodes. In addition, it is
impossible to receive continuous memory area distributed on several
nodes.
The protocol does not demand to support the different tasks of not-
crossed memory space from the separate VM node. The supporting of
multi-thread is not also the obligatory requirement.
The 128-bit Global Job Identifier (GJID) is defined by protocol. It
is assigned on JCP, which will control the job. All active GJID have
the unique values in the unified system at each moment of time.
The job can contain VM code of different types. Different types VM
can be situated on one or different nodes. The mechanism of
association of different VM types in groups on one node is
stipulated, so to the non-uniform code can be executed on one node in
a context of one job. The groups are described in details in section
9. VM, incorporated in groups, must work in common memory space (to
have a common subsystem of memory control).
2.3 System Architecture
System structure, based on using Virtual Machines, is given in the
following figure:
Node 1 Node 2
-------- --------
+--------------------+ +--------------------+
User Application 1 User Application 1
+-----------------------+ +-----------------------+
User Application N User Application N
+--------------------+ +--------------------+
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
VM1 VM2 . . . VMn VM1 VM2 . . . VMn
+--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+

+--------------------------+ +--------------------------+

+-----+ U M S P U M S P
JCP
+-----+ +-------------+------------+
+-------------+------------+
+-----+-----+
+-----+-----+ TCP
TCP +-----+-----+
+-----+-----+

+-----------------/
/------------------+
/

+-----+-----+
Node N TCP
-------- +-----+-----+

+------------+------------+
+-----+
JCP U M S P
+-----+
+-------------------------+
Figure 1. Structure of the system based on use VM.
One or several VM are working on upper level for UMSP. The VM layer
is not network level. Last network level is UMSP. Therefore, VM
layer has no its own network primitives and uses together with UMSP
the same field of operation code.
The end services user of the protocol is the user code, which is
executed by the virtual machine. It has the instructions with the
128-bit address. VM translates these instructions to network
commands, which are transmitted through the UMSP protocol for the
executing by the remote machine. Internal organization VM, command
system and API can be anyone. The protocol defines only format of
primitives, which the virtual machines exchange through a network.
The protocol does not control the jobs memory. Control of memory
should realize VM. If a few VM works on one node, they may have the
common memory space or may be completely isolated.
UMSP uses the transport layer with reliable delivery for the data
exchange. This document defines of using TCP. For the transfer of
not requiring acknowledgement data may be used UDP. Thus, the
connection through TCP is obligatory. Use of multiple connections
TCP with multiplexing is supposed. The control of transport
connections is not the part of the UMSP protocol.
The UMSP instructions do not contain network addresses of the
receiver and sender. The protocol requires that one address UMSP
must correspond to the one transport layer address. Accordingly, it
is necessary to define unequivocal the node address on transport
layer by the 128-bit address of memory.
Except the TCP, it is possible to use other transport protocols or
not network communications. The following requirements are showed to
them:
o Reliable delivery. The transport layer must inform about
delivery or its impossibility;
o The violation of a sequence of transmitted segments is allowed;
o The duplication of segments is not allowed;
o At emergency reload of nodes it is necessary to guarantee
identification of segments concerning session connections,
assigned up to reload;
o Use connectionless-mode is possible.
VM is the independent program and the interaction with the protocol
is necessary for it only when it executes the instructions with the
128-bit address, concerning to other node. VM can execute several
user tasks. Each task can contain several threads of control. VM
must be able to interpret the application instructions with the 128-
bit address to one or several instructions of the UMSP protocol.
The session connection opens between nodes for the data exchange.
One connection is relational only with one job. There may be several
session connections for the different jobs simultaneously between two
nodes. Besides, the protocol provides the connectionless data
exchange.
The exchange between UMSP nodes can include the instructions of the
following type:
o Immediate reading/write in memory;
o Requests of allocation/free memory;
o Comparison instructions;
o Call-subroutine and unconditional jump instructions;
o Synchronization instructions;
o Work with objects instructions - reading / writing in memory of
objects and execution of objects procedures.
UMSP does not trace the user control threads. VM must provide itself
the necessary order of performance of the instructions.
The length of UMSP instructions does not depend on segment length of
the transport layer. The segmentation is provided for transfer of
the long instructions. The packing of the short instructions in one
segment with a possibility of compression of headings is used for its
transfer. The minimal size of necessary for work segment is 6
octets. For realization of all functions, it is necessary 54 octets.
3 Instruction Format
The UMSP instruction includes the basic header, extension headers and
operands. All fields have variable length.
+----------------+----------------------+------------------------+
Header Extension headers Operands
+----------------+----------------------+------------------------+
The header contains operation code and the information necessary for
the instruction interpretation.
The optional extension headers contain the additional information,
not defined in basic header.
The operands contain instructions data.
The instruction format allows calculating common instruction length,
without knowing definition of separate operation code.
The instructions headers provide for the short and extended format
for maintenance of the effective protocol work in wide range of
network speeds. Besides, there is a simple algorithm of the headers
compression.
The all instructions and extension headers the identifiers are given
which enter the name by upper case symbols. The identifiers of the
instructions begin with the letter. The identifiers of the extension
headers begin with underlining symbol.
3.1 Instruction Header
The header has the following format:
Octets:
+0 +1
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
0: OPCODE ASK PCK CHNEXT OPR_LENGTH
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
2: OPR_LENGTH_EXT
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
4: CHAIN_NUMBER
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
6: INSTR_NUMBER
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
8:
+ SESSION_ID +

+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
12:
+ REQ_ID +

+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
OPCODE
1 octet. The operation code. Value of this field is identified by
the instruction. Values of operation codes are divided into the
following intervals:
1 - 112 management instructions
113 - 127 reserved
128 - 223 instructions of exchange between VM
0, 224, 255 reserved
ASK
1 bit. The flag of response necessity. This flag defines
presence of field REQ_ID in header. If ASK = 1, there is field
REQ_ID in the instruction. If EXT = 0, the field REQ_ID in the
instruction are absent.
PCK
2 bits. The Header compression attribute. These bits are used
for packing instructions headers transmitted on one connection TCP
or for sending of the several instructions in one package UDP.
Use of these bits is based on the assumption that two following in
succession instructions concern to one session connection, or one
chain, with a high probability. The PCK bits have one of the
following values:
%b00 - The instruction does not belong to the definite session.
The fields CHAIN_NUMBER, INSTR_NUMBER and SESSION_ID are
absent in header of such instruction.
%b01 - The given instruction concerns to the same session
connection, as previous. The field SESSION_ID in the
instruction header is absent.
%b10 - The given instruction belongs to the same connection and
same chain, as previous. The fields CHAIN_NUMBER,
INSTR_NUMBER and SESSION_ID in header of such instruction
are absent. The INSTR_NUMBER value of the current
instruction calculates by addition of one to INSTR_NUMBER
value of the previous instruction.
%b11 - The given instruction may does not concern to the same
session, as previous. The field SESSION_ID is present at
it. The presence of fields CHAIN_NUMBER and INSTR_NUMBER
is defined by CHN flag.
CHN
1 bit. The flag of chain. Transmitted on one session connection
and concerning one job instructions, may be unified in a chain.
Chains are considered in details by section 7. If SEQ = 1, the
instruction is connected with chain and there are fields
CHAIN_NUMBER and INSTR_NUMBER (if PCK is not set to %b10) at it.
If bit CHN = 0, the instruction is not connected with chains and
there are no fields CHAIN_NUMBER and INSTR_NUMBER in it.
EXT
1 bit. The flag of extension headers presence in the instruction.
If EXT = 1, there is one or more extension headers in the
instruction. If EXT = 0, the extension headers in the instruction
are absent.
OPR_LENGTH
3 bits. The number of 32 bit words in the operands field. The
value 0 defines absence of operands field. The value %b111
specifies use of the extended header format. In the extended
format, the length of operands is defined by the field
OPR_LENGTH_EXT, and the field OPR_LENGTH is not used.
OPR_LENGTH_EXT
2 octets. The number of 32 bit words in the operands field. The
field OPR_LENGTH_EXT is present in header, only if OPR_LENGTH =
%b111. If OPR_LENGTH < > %b111, the field OPR_LENGTH_EXT is
absent. If OPR_LENGTH_EXT = 0, the field of operands is absent.
There are following reasons, on which it is necessary to use field
OPR_LENGTH_EXT instead of OPR_LENGTH:
(1) If operands length must be more than 24 octets
(2) If making the fields alignment of 4 octets is more
effective, than compression of header of 2 octets.
CHAIN_NUMBER
2 octets. The number of chain. This field contains number of
chain, to which the given instruction concerns. The values %x0000
and %xFFFF are reserved.
INSTR_NUMBER
2 octets. The instruction number. This field contains the serial
number of instruction in a chain. The numbering begins with zero.
Value %xFFFF is reserved.
SESSION_ID
4 octets. It is the identifier of the session connection assigned
by the instruction receiver. During the session connection
opening, each side sets its own identifier to connection and
informs it to other side. The zero value of this field specifies
that the instruction does not concern to the definite session.
The value %xFFFFFFFF is reserved.
REQ_ID
4 octets. The request identifier. It is uses for establishment
of correspondence between requests and responds to it.
Further, the identifier OPR_LENGTH is used at the description of the
instructions format. It means using of OPR_LENGTH_EXT field, if
OPR_LENGTH = %b111. The instruction with length of operands, which
are not exceeding 24 octets, may be transmitted with header in the
short format (OPR_LENGTH < > %b111) or in the extended format
(OPR_LENGTH = %b111). Both forms are equivalent.
Minimal header length in the short format is 2 octets, in the
extended format - 4 octets. Maximal header length is 16 octets.
3.2 Extension Headers
If the EXT flag in the instruction header set to 1, the instruction
contains from one up to thirty extension headers. The extension
headers are used for the following purposes:
o For sending of the service information which were not provided in
the basic header.
o For sending of the data of length more than 262240 octets in one
instruction.
The extension headers have the following common format:
Octets:
+0 +1
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
0: HXT HEAD_LENGTH HEAD_LENGTH_EXT
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
2: continued HEAD_LENGTH_EXT
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
4: HSLHOBHRZ HEAD_CODE HEAD_CODE_EXT
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
6: RESERVED
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
8:
/ DATA /
/ /

+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
HXT
1 bit. Specify length of the field of data length. If HXT = 0,
length of the extension header is defined by a field HEAD_LENGTH.
The field HEAD_LENGTH_EXT in this case is absent. If HXT = 1,
length of header is defined by unification of fields HEAD_LENGTH
and HEAD_LENGTH_EXT.
HEAD_LENGTH
7 bit. The number of 16 bit words in DATA field. If HXT = 0,
this is independent field. If HXT = 1, it is the senior bits of
complete length field.
HEAD_LENGTH_EXT
3 octets. The number of 16 bit words in DATA field. If HXT = 0,
this field is absent. If HXT = 1, it is the younger bits of
complete length field.
HSL
1 bit. The flag of last header. It is set to 1 for last
extension header in the instruction. In other extension headers,
this flag is set to 0.
HOB
1 bit. The flag of obligatory processing. It defines the order
of the instruction processing, if the receiving node does not know
purpose of the extension header or cannot process it by any
reason. If HOB = 1, instruction must not be carried out. If HOB
= 0, it does not influence on the instruction processing. The
protocol must process all extension headers, irrespective of
errors presence.
HRZ
1 bit. The field is reserved for the future expansions. This
field must not be analyzed by the protocol on receiving. It must
be set to 0 at sending.
HEAD_CODE
5 bits. If HXT = 0, the field contains the extension header code.
If HXT = 1, this field joins the field HEAD_CODE_EXT. It is the
senior bits of the header code.
HEAD_CODE_EXT
1 octet. If HXT = 0, this field is absent. If HXT = 1, it is the
younger bits of the header code.
RESERVED
2 octets. If HXT = 0, this field is absent. If HXT = 1, this
field is reserved for further use. The field RESERVED must not be
analyzed by the protocol during the receiving in the current
realization of the protocol. It must be set to 0 at sending.
DATA
The data field of the extension header. If HXT = 0, the length of
field is 0 - 254 octets, if HXT = 1, the length is 0 - 4 * 10^9
octets. The format of this field is defined separately for each
value of the header code.
On the receiving side, the extension headers must be processed in
that order, in what they follow in the instruction. If the
instruction contains more than 30 extension headers, it is considered
erroneous. It is necessary to break off the session connection, on
which it was transmitted, after the reception of such instruction.
The identifiers HEAD_LENGTH and HEAD_CODE are used further in the
text at the description of the extended headers format. It assumes
using of fields HEAD_LENGTH + HEAD_LENGTH_EXT and HEAD_CODE +
HEAD_CODE_EXT, if HXT = 1. The headers with the code 0 - 30 can be
sent in short (HXT = 0) and in extended (HXT = 1) format.
3.3 Instruction Operands
The operands field contains the instruction data. The length of
operands field is showed in OPR_LENGTH or OPR_LENGTH_EXT and it is
multiple to four octets. If necessary, 1 - 3 zero-value octets are
padded in the end of a field. Maximal length of operands is 262140
octets. The extension headers are used, if the instruction must
contain longer data.
The format of the operands field is defined separately for each
instruction.
3.4 Address Formats
The following address format numbers are definite for nodes,
immediately connected to the global IPv4 network:
N 4-0-0 (4)
N 4-0-1 (4-1)
N 4-0-2 (4-2)
The appropriate formats of 128-bit addresses:
Octets:
+0 +1 +2 +3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0: 0 1 0 00 00 0 Free
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4: Free
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8: Free IP address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12: IP address Local memory address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0: 0 1 0 00 00 1 Free
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4: Free
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8: Free IP address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12: IP address Local memory address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0: 0 1 0 00 01 0 Free
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4: Free
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8: IP address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12: Local memory address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Free
It is not used by the protocol.
IP address
It sets the node address in the global IPv4 network.
Local memory address
It is described in section 2.1.
IP-address defines the nodes of the given type unequivocally. The
TCP is used for the interaction with such nodes. For sending of not
requiring response instructions, using UDP is allowed. IANA has
assigned ports TCP and UDP 2110. This port must be open for the
listening (receiving). TCP node, initialing the connection opening,
or the UDP node, carrying out the package sending, can use any port.
Using several TCP connections with multiplexing is supposed.
4 Response of the Instructions
The protocol instructions are divided into two types:
(1) The management instructions transmitted on UMSP layer (OPCODE
= 1 - 112).
(2) The instructions of the exchange between VM (OPCODE = 128 -
223).
The processing of two types of the instructions differs as follows:
o The field of the identifier of request REQ_ID is formed by the
protocol in the instructions of the first type, and it is formed
by VM for the instructions of the second type.
o The protocol must analyze the field REQ_ID and compare it with the
instructions, transmitted earlier, after receiving of the response
instruction of the first type.
o The protocol must not analyze the field REQ_ID after receiving of
the response instruction of the second type. This instruction is
simply sent to VM.
The response instructions have the field ASK equal to 1. It means,
that the header have the field REQ_ID. The value taken from the
confirmed instruction is written into the field REQ_ID. The response
instruction does not require response.
A few VM can be connected to the protocol on the node. Everyone VM
can work in its own address space. The identifiers of requests for
different VM can coincide. Therefore, instruction is identified by
two fields:
o The session identifier SESSION_ID, which is connected with
definite VM.
o The request identifier REQ_ID.
4.1 RSP, RSP_P
"Response" (RSP) and "Response of the protocol" (RSP_P) instructions
have the identical format. The difference is only in the operation
code:
OPCODE = 129/1 ; correspondingly to RSP/RSP_P
ASK = 1
PCK = %b01/11
EXT = 0/1
CHN = 0
OPR_LENGTH = 0/1
SESSION_ID and REQ_ID - The values is taken from the confirmed
instruction.
Operands:
2 octets: The basic return code.
2 octets: The additional return code.
The optional extension header:
_MSG - contains the arbitrary error description.
The instruction without operands is used for the positive response.
It is equivalent to zero values of the field of the basic and
additional return codes.
The zero basic return code is used for positive response. The
additional return code may have non-zero value.
The instruction with non-zero basic return code is used for negative
response. The basic return code defines the error category. The
additional return code identifies an error.
The instruction RSP is formed upon the VM request. The return codes
must be received from VM. If the protocol cannot deliver the
requiring response instruction to VM, it forms negative response RSP
independently.
The instruction RSP_P is always formed at the UMSP layer. If the
protocol cannot define on what instruction the RSP_P is transmitted,
nothing actions is executed.
4.2 SND_CANCEL
There can be a necessity to cancel sending after the part of the data
have been already transmitted and have occupied the buffer on the
reception side, by sending of the long fragmented instructions or
transactions. The protocol provides the instruction "The sending is
canceled" (SND_CANCEL) for this purpose. This instruction has the
following fields value:
OPCODE = 2
ASK = 0
PCK = %b01/10/11
EXT = 0/1
CHN = 1
OPR_LENGTH = 1
SESSION_ID - The value is taken from the cancelled chain.
CHAIN_NUMBER - Number of the chain, which sending is cancelled.
INSTR_NUMBER - Always has zero-value.
Operands:
2 octets: The basic return code.
2 octets: The additional return code.
The optional extension header:
_MSG - contains the arbitrary error description.
The instruction SND_CANCEL is used for the cancel of the partially
transmitted transaction or fragmented instruction. At the receiving
the SND_CANCEL instruction, all the earlier received data in the
chain are rejected.
5 Jobs Management
The jobs management includes the following functions:
o Initiation and completion of jobs;
o Initiation and completion of tasks;
o Opening and closing of session connections;
o Activity control of nodes.
The instructions with OPCODE = 1 - 112 are used for jobs management.
These instructions must be sent through TCP. Use UDP is not allowed,
even if the instructions do not demand response.
UMSP bases on model with the centralized control of the separate job.
The reason is that the pointers control is not obviously possible in
the decentralized system. Any task can be finished at any moment or
the node can be reloaded. There is no way guaranteeing the
notification about in the decentralized system all other nodes, on
which the job works. As the job continues to exist - the task
concerning the job can be initiated on the same node again. This
task can allocate new dynamic resources. The addresses for the again
allocated resources can be crossed with addresses of resources, which
existed on the node before the task restart. The old pointers can be
kept on other nodes. It may be the formally correct pointers, but
they will actually specify other objects. The uncontrollable work of
the application can be consequence of such situation.
UMSP solves this task as follows:
o It allows defining the node, on which the task was completed,
precisely.
o If the task on the node is finished before end of the job, all
nodes, on which the job is executed, are notified of it.
o The repeated task initialization on the node is allowed, while all
nodes will receive the message about the first task end.
The protocol does not control the pointers. VM supervises the
pointers correctness. VM must have architecture, in which 128 - bit
pointers are stored in special memory areas, for this purpose. The
protocol informs VM about the nodes, on which task have finished the
work. VM must make all pointers concerning such tasks, invalid. It
results in exclusive situations at the access under these pointers.
If the application provides processing exceptions, it keeps the
capacity for work, or it is finished emergency. Such decision allows
excluding unguided applications working.
For the decision of the specified questions at UMSP level, the
control job node is defined for each job. It names Job Control Point
(JCP). It may be the same node, on which the job is initiated, or it
can be another dedicated node. The basic JCP function is to trace
the initialization and the end of the job tasks. Besides, the
dedicated JCP node may be used for the centralized users
identification and the attack protection.
The following identifiers are definite for the jobs and tasks
control:
o Locally Task Identifier (LTID) is assigned to each active task on
the node. LTID length is equal to the length of local memory
address defined for the node. All LTID on the node must give
unique values at each moment of time. It is allowed to establish
LTID, used earlier in the already completed tasks, for the again
initiated tasks.
o JCP assigned the Control Task Identifier (CTID) to each task of
the job. Its length is equal to length of the local address
memory on the node JCP. All CTID on the JCP must give unique
values at each moment of time. As against LTID, the CTID value is
chosen with some restrictions.
o Globally Task Identifier (GTID) is assigned to each task. GTID
has the same format, as the 128 - bit address of node memory has.
The address of local memory is replaced on LTID in it.
o Globally Job Identifier (GJID) is assigned to the each job. GJID
is defined on the JCP node. It has the same format, as the 128 -
bit address of node JCP memory has. The address of local memory
is replaced on CTID of the first (initial) task of the job in it.
GJID is used in the procedure of session connection opening for
the definition JCP, which controls the job.
LTID and CTID are written at the instructions in the field of length
2/4/8 octets. If the allocated for identifier field in the
instruction is longer than identifier, LTID (CTID) writes in the last
octets. In the initial octets, the value 0 must be written. If
received LTID (CTID) is shorter than the local memory address, it is
necessary to pad it with the zero octets in the beginning.
GTID and GJID are written at the instructions in the field of length
4-16 octets. The field FREE is not present at these identifiers (see
section 2.1). It is considered, that it contains the zero-value
octets. Length of the identifier is defined in header of the
address.
By sending of instructions CONTROL_REQ, TASK_REG and SESSION_OPEN,
the protocol uses timeout. The value of timeout is assigned by node
and must be more than three intervals of the maximal time of delivery
at the transport layer. The timeout is not influenced the waiting
period in queue to the transport layer.
5.1 Job Initiate
The job concerns to the user application executed on VM. The UMSP
job initialization can be made simultaneously with the application
user start or during its working.
The task, appropriated to its job, is initialized on the node
together with the job. LTID is binding to this task.
If the node, on which the user application was loaded, is chosen for
JCP, the question of the job initialization lays beyond the scope of
the network protocol.
Other node can be chosen as JCP for the following reasons:
o The job initialization node is connected to network by slow-speed
or overloaded channel. It is undesirable to send the managing
traffic.
o The node has no computing possibilities for conducting the
managing tables.
o The authentication on the detailed node is necessary.
If the other node is chosen for JCP, the node, that initiates the
job, must register the job at JCP.
5.1.1 CONTROL_REQ
The instruction "To request a control" (CONTROL_REQ) is sending from
the node, initial the job, to JCP of other node. The instruction has
the following values of fields:
OPCODE = 3
PCK = %b00
CHN = 0
ASK = 1
EXT = 0/1
OPR_LENGTH = 2/3 ; Depends on LTID length.
REQ_ID - The value is assigned by the sender node protocol and
then will be sent in the response.
Operands:
4 octets: The control parameters profile. This field has the
following format:
bits
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+

+ JOB_LIFE_TIME +

+-----+-----+-----+-----+-----+-----+-----+-----+
CMT Reserved VERSION
+-----+-----+-----+-----+-----+-----+-----+-----+
Reserved
+-----+-----+-----+-----+-----+-----+-----+-----+
JOB_LIFE_TIME
2 octets. The job lifetime in seconds. The zero-value
signifies that the restriction of the job lifetime is
unused.
CMT
1 bit. The flag of several JCP using. This field is
reserved for the future expansion of the protocol.
VERSION
1 octet. The number of the UMSP version. It must
contain the value 1.
Reserved
3 + 8 bits. All bits must be set to 0.
4/8 octet: LTID of task of the job, assigned on the node, which
initiate the job (by the sender of this
instruction).
The optional extension headers:
_JOB_NAME - This header contains the name of the Job. Is
assigned once and must not change further.
_INACT_TIME - This header contains the inaction time (see
section 5.7).
At reception of the CONTROL_REQ instruction JCP checks the LTID value
from the received instruction and makes the following:
(1) If the node, which has sent CONTROL_REQ, already has registered
on JCP the active job with such LTID, the notification about
abnormality end of the registered job is sent, as is described in
section 5.5.2 (it is considered, that the node was reloaded).
After that, the sanction to an initiation of the new job is sent.
(2) If the node has no registered job with received LTID, it allows
the new job initiation at once.
If JCP confirms the control, it will send the instruction
CONTROL_CONFIRM, or else CONTROL_REJECT.
5.1.2 CONTROL_CONFIRM
The instruction "To confirm the control" (CONTROL_CONFIRM) is sent
from JCP as the positive response to CONTROL_REQ instruction.
CONTROL_CONFIRM has the following values of fields:
OPCODE = 4
PCK = %b00
CHN = 0
ASK = 1 ; The instruction does not need to be responded. This flag
specifies presence of the REQ_ID field.
EXT = 0/1
OPR_LENGTH = 1-4 ; Depends of length of the GJID.
REQ_ID - The value is taken from the instruction CONTROL_REQ
Operands:
4-16 octets: The GJID assigned to the job on the JCP.
The sending of the instruction CONTROL_REQ means request of control
and request of task initiation. Assigned to the task CTID is part
GJID (field of the local memory address).
5.1.3 CONTROL_REJECT
The instruction "To reject the control" (CONTROL_REJECT) is sent from
JCP as the negative response to CONTROL_REQ instruction.
CONTROL_REJECT has the following values of fields:
OPCODE = 4
PCK = %b00
CHN = 0
ASK = 1. The instruction does not need to be responded. This flag
specifies presence of the REQ_ID field.
EXT = 0/1
OPR_LENGTH = 1/2 ; Depends on presence of the control parameters
profile field.
REQ_ID - The value is taken from the instruction CONTROL_REQ
Operands:
2 octets: The basic error code. The zero-value is not
available.
2 octets: The additional error code.
4 octets: The control parameters profile (see section 5.1.1),
that is allowed by JCP. This is optional field.
The optional extension headers:
_INACT_TIME - This header contains the inaction time (see
section 5.7).
_MSG - contains the arbitrary error description.
5.2 Task Initiate
The job is executed on several nodes simultaneously. The task,
appropriate to it, must be initialized on each node. There is
corresponding only one task to one job on the node. Each task must
be connected only with one job.
The task is initiated together with the job on the node, which had
created the job. On the other nodes, the task is initiated during
the receiving of the first request on the opening of the session
connection, which is appropriate to the job. The request about
openings of session connection contains GJID. GJID contains the JCP
address. It is necessary to receive the sanction from JCP for the
task start. If the request about the opening of session has been
received from JCP node, it is not necessary to request the sanction.
5.2.1 TASK_REG
The instruction "To register a task" (TASK_REG) is sent from the
node, which initials the task, to JCP of the remote node. The
instruction has the following values of fields:
OPCODE = 6/7/8 ; For length CTID of 2/4/8 octets.
PCK = %b00
CHN = 0
ASK = 1
EXT = 0/1
OPR_LENGTH = 2-8 ; Depends on length of the GTID and LTID.
REQ_ID - The value is assigned by the sender node protocol and
then will be sent in the response.
Operands:
2/4/8 octets: CTID of the task initiated the job. It CTID is a
part GJID from the instruction SESSION_OPEN.
4-16 octets: GTID, assigned on the node, initialed session
connection. GTID is formed of sender addresses (at
transport layer) and field LTID of the instruction
SESSION_OPEN.
2/4/8 octets: LTID, assigned on the node, initialed the task
(by the sender of this instruction).
The optional extension headers:
_INACT_TIME - This header contains the inaction time (see
section 5.7).
The instruction TASK_REG must be sent only if the task with given
GJID was not initiated on the node.
JCP confirms initiation of a task at observance of the following
conditions:
(1) Task with received GTID already has registered on JCP.
(2) Task with LTID for the node requesting for initiation has not
registered.
In all other cases, JCP will not confirm a task.
If JCP confirms the task, it will send the instruction TASK_CONFIRM,
differently TASK_REJECT.
5.2.2 TASK_CONFIRM
The instruction "To confirm the task" (TASK_CONFIRM) is sent from JCP
as the positive response to TASK_REG. TASK_CONFIRM has the following
values of fields:
OPCODE = 9
PCK = %b00
CHN = 0
ASK = 1. The instruction does not need to be responded. This flag
specifies the field REQ_ID presence.
EXT = 0/1
OPR_LENGTH = 1/2 ; Depends on length of the CTID.
REQ_ID - The value is taken from the instruction TASK_REG.
Operands:
4/8 octets: The CTID assigned to the task on the JCP.
The optional extension headers:
_JOB_NAME - This header contains the name of the Job.
5.2.3 TASK_REJECT
The instruction "To reject the task" (TASK_REJECT) is sent from JCP
as the negative response to TASK_REG instruction. TASK_REJECT has
the following values of fields:
OPCODE = 10
PCK = %b00
CHN = 0
ASK = 1. The instruction does not need to be responded. This flag
specifies presence of the REQ_ID field.
EXT = 0/1
OPR_LENGTH = 1
REQ_ID - The value is taken from the instruction CONTROL_REQ
Operands:
2 octets: The basic error code. The zero-value is not
available.
2 octets: The additional error code.
The optional extension headers:
_INACT_TIME - This header contains the inaction time (see
section 5.7).
_MSG - contains the arbitrary error description.
5.2.4 TASK_CHK
With the purposes of a safety the node, which have received request
about the opening of session connection, may check up at JCP the
node, which has initialed connection, even if the task was already
initiated.
The instruction "To check up the task" (TASK_CHK) is sent from the
node, which has received the instruction of the establishment of
session connection SESSION_OPEN, to JCP. The task with given GJID,
must have existed on the node already. The instruction TASK_CHK
format coincides with TASK_REG. OPCODE = 11. The response to the
instruction TASK_CHK JCP forms instructions TASK_REG similarly.
JCP confirms the instruction TASK_CHK if a task with received GTID
and LTID already has registered on JCP.
The sending of the TASK_CHK is optional.
5.3 Establishment of session connection
The session connection is established between two tasks of one job.
The connection is established under the VM initiative and it is used
for the exchange of the instructions between VM.
One session connection must be connected only with one task on the
node. The task may have several connections with different nodes.
Between two nodes must be only one session connection with one GJID.
The request about the establishment of session connection contains
the global identifier of the job GJID. If the node receives the
request about the establishment of connection with GJID, which is not
presented on the given node, VM must create a new task. If the task
has been already initialized, the new task is not created.
The session connection needs to be established over TCP. After the
connection is established, the sending of the instructions, which are
not require of execution response, is possible through UDP. One TCP
connection may be used by several session connections. One session
connection may use several TCP connections.
The protocol allows working without the establishment of session
connection. The node must have VM by default, which must execute the
instructions without the establishment of connection.
At the establishment of session connection, the sides agree about the
used VM type and the subset of the protocol functions. The session
connection UMSP may be asymmetrical. It means, that two sides of one
connection can be connected with VM of the different type and provide
the different subset of the protocol functions.
If at an establishment of session connection the zero-type VM is
used, it specifies group VM (see section 9). The zero-value of
realization VM is not allowed.
The procedure of the establishment of session connection may contain
from 2-way up to 8-way handshakes.
5.3.1 SESSION_OPEN
The instruction "To open a session" (SESSION_OPEN) is used for the
initiation of session connection and for the specification of
connection parameters during handshake. It has the following values
of fields:
OPCODE = 12
PCK = %b00/11. In the first instruction (initial) the value of
this field is set to %b00. In all subsequent -
%b11.
CHN = 0
ASK = 1
EXT = 0/1
OPR_LENGTH = 6 - 10 ; Depends on length GJID and LTID.
SESSION_ID - In the first instruction this field is absent. In all
subsequent, it contains the identifier of sessions,
assigned by the instruction receiver.
REQ_ID - This field contains the session connection identifier,
assigned by the instruction sender.
Operands:
2 octets: The VM type required from the addressee.
2 octets: The VM version required from the addressee.
4 octets: The profile of connection required from the
instruction addressee.
2 octets: The VM type of the sender.
2 octets: The VM version of the sender.
4 octets: The profile of connection given by the instruction
sender.
2 octets: The number of 256 octet blocks in the buffer,
allocated for session ("window"), on the side of the
sender of this instruction (see section 7.4). The
zero-value specifies absence of the buffer.
4-16 octets: GJID.
4/8 octets: LTID of the sender task, assigned on the node -
sender of the instruction. It is used in the
instruction TASK_REG (as a part of the field GTID).
If the VM type and version, required from the addressee, have the
value 0, the receiving node independently chooses the VM type and
reports it in the response. The establishment of connection without
binding to VM or VM group is not allowed.
Totally, it can be transmitted up to 7 instructions SESSION_OPEN at
the establishment of connection. The instruction SESSION_ACCEPT is
used for the response of the establishment of connection. For the
refusal of connection the instruction, SESSION_REJECT is used.
It is possible to refuse connection on any step. It is necessary
either to confirm connections, or to refuse it on the eighth step.
During the establishment of connection the following parameters may
be changed:
o VM type and VM version;
o profiles of connection.
If the repeated request about opening of session connection is
received from the definite node, while one connection with received
GJID have been already established, the following variants are
possible:
(1) If the request has arrived from the node JCP, it is necessary:
o To finish the existing task emergency and to deallocate all
dynamic resources belong to it.
o To initiates a task without request of the JCP sanction again.
o To confirm the establishment of connection.
(2) If the request arrived not from the JCP node, it is necessary to
refuse the establishment of new session connection. The existing
task does not need to be changed.
5.3.2 SESSION_ACCEPT
The instruction "To accept the session" (SESSION_ACCEPT) is used for
positive response to the establishment of session connection. It has
the following values of fields:
OPCODE = 13
ASK = 1
PCK = %11
EXT = 0/1
CHN = 0
OPR_LENGTH = 0
SESSION_ID - This field contains the session connection identifier
of assigned by the node of the addressee of the
instruction.
REQ_ID - This field contains the session connection identifier,
assigned by the instruction sender.
5.3.3 SESSION_REJECT
The instruction "To reject the session" (SESSION_ACCEPT) is used for
negative response to the establishment of session connection. It has
the following values of fields:
OPCODE = 14
ASK = 0
PCK = %b11
EXT = 0/1
CHN = 0
OPR_LENGTH = 1
SESSION_ID - This field contains the session connection identifier
of assigned by the node of the addressee of the
instruction.
Operands:
2 octets: The basic error code. The zero-value is not
available.
2 octets: The additional error code.
The optional extension headers:
_MSG - contains the arbitrary error description.
5.3.4 Connection Profile
The profile of connection is defined in 4-octet field of flags. The
flags have identifiers S0 - S31. The number in the identifier is
defining the serial number of bit. If the flag is set to 1, the
function, connected with it, is provided. If the flag is set to 0,
the function, connected with it, is not provided (not required). The
list of functions, determined at the establishment of session
connection, are described further.
Work with chains:
S0 - Use of fragmented instructions.
S1 - Use of sequences.
S2 - Use of transactions.
Establishment of connection:
S3 - Use the exchange of the data without the establishment of
connection.
S4 - Use the exchange of the data with the establishment of
connection.
The instructions format:
S5 - Reserved. Must have set to 0.
S6 - Use of 16-octet address in the exchange instructions.
S7 - Use of the compressed form of header of the instruction
(OPR_LENGTH < > %b111) is allowed
S8 - Use of the extension form of header of the instruction
(OPR_LENGTH = %b111) is allowed
S9 - Use of the extension headers with the data field up to 254
octets of length.
S10 - Use of the extension headers with the data field up to 4 *
10^9 octets of length.
S11-S15 Maximal length of the data field in operands in the 4
octet words. These bits are the common field. Maximal
length in octets is computed under the formula:
<max length> = (<value of this field> + 1) * 4.
If the value is equal %b1111, maximal length of the data
is defined by the instruction format.
S16-S19 These bits are the common field. In the profile required
from the addressee of the i