RFC 3018
Unified Memory Space Protocol Specification
Pages: 81
Experimental
Experimental
Part 1 of 4 – Pages 1 to 21
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 |CHN|EXT| 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: |HSL|HOB|HRZ| 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 0|0 0|0 0| Free |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4: | Free |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8: | Free | IP address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12:| IP address | Local memory address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0: |0 1 0 0|0 0|0 1| Free |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4: | Free |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8: | Free | IP address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12:| IP address | Local memory address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0: |0 1 0 0|0 0|1 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.
(page 21 continued on part 2)