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SEMI E37-0303 © SEM 1995, 2003 3 unconfirmed service (HSMS) — a n H S M S s e r v i c e requested by sending a message from the initiator to the responding entity which requ ires no indication of completion from the resp…

SEMI E37-0303 © SEMI 1995, 2003 2

IP Address — Internet Protocol Address. A logical

address which uniquely identifies a particular

attachment to a TCP/IP network.

local entity — relative to a particular end point of a

connection, the local entity is that entity associated with

that endpoint.

local entity-specific — general qualifier to any

procedure, option, issue, or other implementation

matter which is not a subject of this standard and left to

the discretion of the individual supplier.

message — a complete unit of communication in one

direction. An HSMS Message consists of the Message

Length, Message Header, and the Message Text. An

HSMS Message can be a Data Message or a Control

Message.

message length — a 4-byte unsigned integer field

specifying the length of a message in bytes.

open transaction — a transaction in progress.

port — an endpoint of a TCP/IP connection whose

complete network address is specified by an IP Address

and TCP/IP Port number.

port number — (or TCP port number). The address of

a port within an attachment to a TCP/IP network which

can serve as an endpoint of a TCP/IP connection.

primary message — an HSMS Data Message with an

odd numbered Function. Also, the first message of a

data transaction.

published port — a TCP/IP IP Address and Port

number associated with a particular entity (server)

which that entity intends to use for receiving TCP/IP

connection requests. An entity' s published port must be

known by remote entities intending to initiate

connections.

receiver — the HSMS Entity receiving a message.

remote entity — relative to a particular endpoint of a

connection, the remote entity is the entity associated

with the opposite endpoint of the connection.

reply — an HSMS Data Message with an even-

numbered function. Also, the appropriate response to a

Primary HSMS Data Message.

responding entity (HSMS) — the provider of an HSMS

service. The responding entity receives a message from

an initiator requesting the service. In the event of a

confirmed service, the responding entity indicates

completion of the requested service by sending an

appropriate HSMS response message to the initiator of

the request. In an unconfirmed service, the responding

entity does not send a response message.

session — a relationship established between two

entities for the purpose of exchanging HSMS messages.

session entity — an entity participating in an HSMS

session.

session ID — a 16-bit unsigned integer which identifies

a particular session between particular session entities.

stream (TCP/IP) — a sequence of bytes presented at

one end of a TCP/IP connection for delivery to the

other end. TCP/IP guarantees that the delivered

sequence of bytes matches the presented stream.

HSMS subdivides a stream into blocks of contiguous

bytes - messages.

T3 — reply timeout in the HSMS protocol.

T5 — connect Separation Timeout in the HSMS

protocol used to prevent excessive TCP/IP connect

activity by providing a minimum time between the

breaking, by an entity, of a TCP/IP connection or a

failed attempt to establish one, and the attempt, by that

same entity, to initiate a new TCP/IP connection.

T6 — control Timeout in the HSMS protocol which

defines the maximum time an HSMS control

transaction can remain open before a communications

failure is considered to have occurred. A transaction is

considered open from the time the initiator sends the

required request message until the response message is

received.

T7 — connection Idle Timeout in the HSMS protocol

which defines the maximum amount of time which may

transpire between the formation of a TCP/IP connection

and the use of that connection for HSMS

communications before a communications failure is

considered to have occurred.

T8 — network Intercharacter Timeout in the HSMS

protocol which defines the maximum amount of time

which may transpire between the receipt of any two

successive bytes of a complete HSMS message before a

communications failure is considered to have occurred.

TCP/IP — Transmission Control Protocol/Internet

Protocol. A method of communications which provides

reliable, connection-oriented message exchange

between computers within a network.

TLI — Transport Level Interface. One particular API

provided by certain implementations of TCP/IP which

provides a transport protocol and operating system

independent definition of the use of any Transport

Level protocol.

transaction — a Primary Message and its associated

Reply message, if required. Also, an HSMS Control

Message of the request (.req) type, and its response

Control Message (.rsp), if required.

SEMI E37-0303 © SEM 1995, 2003 3

unconfirmed service (HSMS) — an HSMS service

requested by sending a message from the initiator to the

responding entity which requires no indication of

completion from the responding entity.

5 HSMS Overview and State Diagram

High-Speed SECS Message Services (HSMS) defines a

communication interface suitable for the exchange of

messages between computers in a semiconductor

factory using a TCP/IP environment. HSMS uses

TCP/IP stream support, which provides reliable two

way simultaneous transmision of streams of contiguous

bytes. It can be used as a replacement for SECS-I

communication as well as other more advanced

communications environments.

The procedure for HSMS communications parallels the

more familiar SECS-I communications it replaces. The

following steps are followed for any communications

(HSMS or otherwise):

1. Obtain a communications link between two

entities. In SECS-I, this is the RS232 wire

physically connecting host and equipment. In

HSMS, the link is a TCP/IP connection obtained by

the standard TCP/IP connect procedure. Note that

the abstract term “entity” is used instead of “host”

or “equipment.” This is because, while HSMS is

used for SECS-I replacement, it has more general

applications as well. In a SECS-I replacement

application, the “host” is an “entity” and the

“equipment” is an “entity.”

2. Establish the application protocol conventions to

be used for exchanging data messages between two

entities. For SECS-I, this step is implicit in the fact

that semiconductor equipment is physically

connected on the two ends of the wire: the protocol

is SECS-II.

In the case of HSMS, the communications link is a

dynamically established TCP/IP connection on a

physical link which may be shared with many other

TCP/IP connections using protocols other than

HSMS or connections using non TCP/IP protocols.

HSMS adds a message exchange (called the Select

procedure) which is used to confirm to both entities

that the particular TCP/IP connection is to be used

exlusively for HSMS communications.

3. Exchange Data. This is the normal intended

purpose of the communications link. In both

SECS-I and HSMS, the procedure is to exchange

SECS-II encoded messages for the control of

semiconductor equipment and/or processes. Data

exchange normally continues until one or both of

the entities are taken off-line for equipment-

specific purposes, such as maintenance.

4. Formally end communications. In SECS-I, there is

no formal requirement here; the equipment to be

taken off-line stops communicating.

In HSMS, a message exchange (either the

“bilateral” Deselect procedure or the “unilateral”

separate procedure) is used for both parties to

confirm that the TCP/IP connection is no longer

needed for HSMS communications.

5. Break the communications link. In SECS-I, this is

done by physically unplugging the host or

equipment from the communications cable, which

only occurs during repair or physical

reconfiguration of the factory network

environment.

In HSMS, since it uses the dynamic connection

environment of TCP/IP, the TCP/IP connection is

logically broken via a release or a disconnect

procedure without any physical disconnect from

the network medium.

Two additional procedures, of a diagnostic nature, are

supported in HSMS, which are generally not required

by a simple SECS-I link or a SECS-I direct

replacement. These follow:

1. Linktest. This procedure provides a simple

confirmation of connection integrity.

2. Reject. Because HSMS is intended to be extended

to protocols other than just SECS-II (by means of

subsidiary standards), it is possible that two entities

can be connected (due to a configuration error)

which use incompatible subsidiary standards. Also,

during initial implementation, incorrect message

types may be sent, or they may be sent out of order

due to software bugs. The reject procedure is used

to indicate such an occurrence.

5.1 HSMS Connection State Diagram — The HSMS

state machine is illustrated in the diagram below. The

behavior described in this diagram defines the basic

requirements of HSMS: subsidiary standards may

further extend these or other states.

5.2 State Descriptions

5.2.1 NOT CONNECTED — The entity is ready to listen for or initiate TCP/IP connections but either has not yet

established any connections or all previously established TCP/IP connections have been terminated.

5.2.2 CONNECTED — A TCP/IP connection has been established. This state has two substates, NOT SELECTED

and SELECTED.

5.2.2.1 NOT SELECTED — A substate of CONNECTED in which no HSMS session has been established or any

previously established HSMS session has ended.

5.2.2.2 SELECTED — A substate of CONNECTED in which at least one HSMS session has been established. This

is the normal “operating” state of HSMS: data messages may be exchanged in this state. It is highlighted by a heavy

outline in the state diagram.

5.3 State Transition Table

Table 1

# Current State Trigger New State Actions Comment

1 ... Local entity-specific

preparation for TCP/IP

communication.

NOT CONNECTED Local entity-specific Action depends on

connection procedure to be

used: active or passive.

2 NOTCONNECTED A TCP/IP connection is

established for HSMS

communication.

CONNECTED -

NOT SELECTED

Local entity-specific none

3 CONNECTED Breaking of TCP

connection.

NOT CONNECTED Local entity-specific See Section 6.4.

4 NOT SELECTED Successful completion of

HSMS Select Procedure.

SELECTED Local entity-specific HSMS communication is

now fully established: data

message exchange is

permitted.

5 SELECTED Successful completion of

HSMS Deselect or

Separate.

NOT SELECTED Local entity-specific This transition normally

indicates the end of HSMS

communication and so an

entity would immediately

proceed to break the TCP/IP

connection (transition 3

above).

6 NOT SELECTED T7 Connection Timeout. NOT CORRECTED Local entity-specific per Section 9.2.2