XOM Call Control (XCC)
XOM Call Control (XCC) Specification
About This Manual
This is Edition 7.20141001, last updated 2014-10-25, of
The XOM Call Control (XCC) Specification, for Version
1.1 release 7.20141001 of the
OpenSS7 package.
Preface
Notice
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This document is released under the FDL (see GNU Free Documentation License) with no invariant
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Abstract
This document is a Specification containing technical details concerning the implementation of
the XOM Call Control (XCC) for OpenSS7. It contains recommendations on software architecture as well
as platform and system applicability of the XOM Call Control (XCC).
This document specifies a XOM Call Control (XCC) Specification in support of the OpenSS7 Call Control
(CC) protocol stacks. It provides abstraction of the Call Control interface to these
components as well as providing a basis for Call Control control for other Call Control protocols.
Purpose
The purpose of this document is to provide technical documentation of the XOM Call Control (XCC).
This document is intended to be included with the OpenSS7 STREAMS software package released
by OpenSS7 Corporation. It is intended to assist software developers, maintainers and users
of the XOM Call Control (XCC) with understanding the software architecture and technical interfaces
that are made available in the software package.
Intent
It is the intent of this document that it act as the primary source of information concerning the
XOM Call Control (XCC). This document is intended to provide information for writers of OpenSS7
XOM Call Control (XCC) applications as well as writers of OpenSS7 XOM Call Control (XCC) Users.
Audience
The audience for this document is software developers, maintainers and users and integrators of the
XOM Call Control (XCC). The target audience is developers and users of the OpenSS7 SS7 stack.
Revision History
Take care that you are working with a current version of this documentation: you will not be
notified of updates. To ensure that you are working with a current version, check the
OpenSS7 Project website for a current version.
A current version of this specification is normally distributed with the OpenSS7
package, openss7-1.1.7.20141001.1
Version Control
Although the author has attempted to ensure that the information in this document is complete and
correct, neither the Author nor OpenSS7 Corporation will take any responsibility in it.
OpenSS7 Corporation is making this documentation available as a reference point for the
industry. While OpenSS7 Corporation believes that these interfaces are well defined in this
release of the document, minor changes may be made prior to products conforming to the interfaces
being made available. OpenSS7 Corporation reserves the right to revise this software and
documentation for any reason, including but not limited to, conformity with standards promulgated by
various agencies, utilization of advances in the state of the technical arts, or the reflection of
changes in the design of any techniques, or procedures embodied, described, or referred to herein.
OpenSS7 Corporation is under no obligation to provide any feature listed herein.
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Acknowledgements
The OpenSS7 Project was funded in part by:
Thanks to the subscribers to and sponsors of The OpenSS7 Project.
Without their support, open software like this would not be possible.
As with most open source projects, this project would not have been possible without the valiant
efforts and productive software of the Free Software Foundation, the
Linux Kernel Community, and the open source software movement at large.
1 Introduction
1.1 Overview
The XOM Call Control Programming Interface (abbreviated XCC) defines an
Application Program Inteface (API) to call control services. It is referred to as the
interface throughout this specification.
The interface is designed to offer services that are consistent with, but not limited to, the ITU-T
Recommendation Q.761, Q.931, H.225.0 and IETF SIP-T standards. These standards were published in 1997 and have
been stable for many years.
The interface is also designated to offer services that are consistent with the 3GPP TS 28.001
standards for GSM mobile networks.
All of the above standards are referred to in this document as the Standards.
Access to other call control services through the API is not prohibited, but has not been
explicitly considered.
The interface is designed to be used and implemented in conjunction with the use and implementation
of the general-purpose XOM API (reference XOM).
A brief introduction to Call Control Services is given in Introductory Concepts.
Following this is an overview of OSI-Abstract-DATA Manipulation OM, which provides the Data
Abstraction service as defined in the XOM specification (reference XOM). Then the optional features of
this specification are described, and the chapter closes with a list of abbreviations. In all cases
the reader should refer to the Standards (reference ISUP, reference ISDN, reference H.323, or to the XOM Specification
(reference XOM) for further authoritative details.
The structure of the remaining chapters and appendices are described in the Preface.
1.2 Format of the Specification
This specification describes a programming language-independent interface to the Call Control
Services together with a specific C language binding of that interface. Several conventions are
used to identify particular items. The general conventions are described in the Preface,
while the C language binding conventions are described in C Language Binding.
1.3 Introductory Concepts
1.3.1 Relationship to Call Control Protocols
The interaction between call control programs acting in a call control entity role are
realized through the exchange of call control service information. The general
communications service for the call control applications is the Call Control Protocol. Call
control protocols define the following operations:
This communication may be accomplished using the ITU-T or ANSI Message Transfer Part protocol.
1.3.2 XCC and the Call Control Provider
The XCC interface provides access to the CC service provider, which offers all of the facilities
defined in the Standards. It also provides facilities such as automatic association management and
automatic session handling. The interface is designed not to restrict the services offered to those
of specific service packages of ISUP.
The interface defined in this specification is “symmetrical” in the sense that it can be used to
implement call control programs acting in any of the CC producer or consumer roles (e.g. MSC,
BSC). The interface supports:
- a call control program acting as a consumer of call control services. This is
done by submitting service operation requests and receiving service operation responses.
- a call control program acting as a producer of call control services. This is
done by receiving service operation requests and sending back service operation responses.
The interface provides the ability to send requests on the consumer side and to receive
indications on the producer side within a call control interaction. Furthermore, if the
service is confirmed, the producer will be able to send back responses that will be received
as confirmations by the consumer.
1.4 Relationship to ISUP, ISDN, H.323 and SIP-T
The API is essentially based on the abstract services of the ITU-T ISUP and ISDN, but is
independent of the underlying communications stack. The API allows the manipulation of ITU-T and
ANSI call control service information. Thus this API does not preclude and does not force the
use of either the ITU-T ISUP protocol or the ANSI ISUP protocol.
The XCC API offers several abstract call control service views: the on of ISUP, the one of ISDN,
the one of H.323, the one of GSM BSSAP, and that of SIP-T.
The contents of ITU-T ISUP messages are described in ITU-T Recommendation Q.761. These messages
implicitly define the ITU-T ISUP services. The mapping between ITU-T ISUP services and various
service primitives and parameters of the XCC API are described below.
The services offered by the XCC API are a superset of those defined by ITU-T and ANSI.
The general communication protocol for ANSI ISUP is the MTP as specified in ANSI T1.113.4/200. The
general communication protocol for ITU-T ISUP is the MTP as specified in ITU-T Recommendation series
Q.761 through Q.764.
The abstract call control views of XCC (ITU-T and ANSI, ISUP, ISDN, H.323, BSSAP or SIP-T) are
independent of the underlying protocol. However, the ITU-T view on top of ANSI MTP requires that an
appropriate mapping of ITU-T ISUP services over ANSI MTP is widely available.
1.5 Relationship to Data Abstraction Services
XCC is dependent on standard data abstraction services to ensure portability of call control software
written to the XCC specification. XCC functions pass most arguments by reference. The data
referenced by these arguments is modelled and manipulated in an object-oriented fashion. Call
application data abstraction services are provided by the XOM API (reference XOM).
The definitions below introduce the various concepts that are used by Call Control data
abstraction services.
- Syntax
A syntax is the classification and representation of values in OSI-Abstract-Data Manipulation.
Examples of syntaxes are Boolean, Integer, Real, String(Octet),
String(Object-Identifier) and Object.
- Value
A value is a single datum, or piece of information. A value may be as simple as a Boolean
value (for example, True), or as complicated as an entire OM object (for example, a
Message).
- OM Attribute
An OM attribute type is an arbitrary category into which a specification places some values.
An OM attribute is an OM Attribute Type, together with an ordered sequence of one or more
values. The OM Attribute Type can be thought of as the name of the OM attribute.
- OM Object
An OM object is a collection of OM attributes.
- OM Class
An OM class is a category of OM objects set out in a specification. It determines the OM
attributes that may be present in the OM object, and details the constraints on those OM attributes.
- Package
A Package is a set of OM classes that are grouped together by the specification, because tey
are functionally related (for example, ISUP service package).
- Package Closure
A Package-Closure is the set of classes that need to be supported to be able to create all
possible instances of all classes defined in the package. Thus an OM Class may be defined to have
an OM Attribute whose value is an OM Obejct of an OM Class that is defined in some other package,
but within the same Package-Closure.
- Workspace
A workspace is allocated storage that contains one or more Package-Closures, together
with an implementation of the Call Control data abstraction services, that supports all the OM
classes of OM objects in the Package-Closures.
- Descriptor
A descriptor is a defined data structure that is used to represent an OM Attribute Type and a
single value. The structure has three components: a type, a syntax and a value.
- Public Object
Public Objects are represented by data structures that are manipulated directly using
programming language constructs. Use of Public Objects therefore simplifies programming by this
direct access and by enabling objects to be statically defined, when appropriate. Programs can
efficiently access public objects.
- Private Objects
Private Objects are held in data structures that are private to the service and can only be
accessed from programs indirectly using interface functions. They are of particular use for
structures that are infrequently manipulated by programs, being passed by reference to the service,
which can then manipulate them efficiently. An example of such objects in XCC is the session
object.
1.6 Mandatory and Optional Features
The interface defines an Application Program Interface (API) that application programs can use to
access the functionality of the underlying Call Control Services. The interface does not
define or imply any profile of that service.
Note that nothing in this specification requires that the implementation of the interface or the
Call Control Services itself acutally makes use of TCAP or other parts of the model, just so
long as it provides the defined service. Also, the scope of the Call Control Services
to which an application has access is not determined; it is not restricted to ITU-T ISUP operations.
Some OM attributes are optional: these are marked (Optional Functionality) in the OM class
definitions. They are:
- File-Descriptor in a Session object.
Some items of behaviour of the interface and a number of aspects of the Call Control Services
provider are implemetnation-defined. These are:
- the maximum number of oustanding asynchronous operations
- whether an asyncrhonous function call returns before the operation is submitted to the Call
Control Services provider
- the text and language of error messages
- the OM classes permitted as values of the
Address and Title argument to
interface functions.
The default values of some OM attributes on OM object Session are locally administered.
This API assumes the provision of automatic association management and automatic session handling by
the CC provider.
The interface enables negotiation of the use of the various defined features of the CC provider and
those of the interface.
1.7 Packages
The specification defines three Call Control packages (Common CC package, ITU-T CC package and
ANSI CC package), Interface Class Definitions. These packages define the OM classes required
by the interface functions to perform ITU-T CC or ANSI CC services. The Common CC package, which
also includes the errors defined (see Errors), is mandatory. The ITU-T CC package and the ANSI
CC package are optional, but at least one of them must be supported by the implementation. The
ITU-T service view and the ANSI service view assume the support of the corresponding ITU-T CC or ANSI
CC package by the implementation.
The use of the optional packages is negotiated using the Negotiate() function.
1.8 Terminology
The terms implementation-defined, may, should, undefined, unspecified,
and will are used in this document with the meanings ascribed to them in reference XPG4,
see also Glossary.
1.9 Abbreviations
| API | Application Program Interface |
| ANS.1 | Abstract Syntax Notation One |
| ANSI | American National Standards Institute |
| BER | Basic Encoding Rules |
| GSM | Global Services Mobile |
| ISO | International Organisation for Standardisation |
| ITU-T | Internation Telecommunications Union - Telecom Sector |
| MAP | Mobile Application Part |
| OM | OSI-Abstract-Data Manipulation |
| OSI | Open Systems Interconnect |
| ROSE | Remote Operations Service Element |
| TCAP | Transaction Capabilities Application Part |
| XMAP | XOM Mobile Application Part API |
| XOM | X/Open: OSI-Abstract-Data Manipulation API |
2 C Language Binding
This chapter sets out certain characteristics of the C language binding to the interface. The
binding specifies C identifiers for all the elements of the interface, so that application programs
written in C can access the Mobile Application Services. These elements include function names,
typedef names and constants. All of the C identifiers are mechanically derived from the
language independent names as explained below. There is a complete list of all the identifiers in
C Headers. For ease of use, some of these identifiers are defined in the specification
alongside the language-independent name.
A Function() is indicated as shown.
A CONSTANT is in Roman font.
The names of [[ERRORS]] and other return codes are surrounded by square brackets.
The definitions of the C identifiers appear in four headers:
- <xom.h>
This header file contains definitions for the associated OM interface.
- <xcc.h>
This header file contains common definitions for the access to the Mobile Application Part service
(see Interface Functions, and ‘Common CC Package’). A listing of this header file is
provided in xcc.h.
- <xcc_gsm.h>
This header file contains specific definitions that reflect the Abstract Services of the ITU-T Mobile
Services along with the ASN.1 productions of the related protocol (ITU-T CC), See ‘ITU-T CC Package’.
A listing of this header file is provided in ‘xcc_gsm.h’.
- <xcc_ansi.h>
This header file contains specific definitions that reflect the Abstract Services of the ANSI Mobile
Services allong with the ASN.1 productions of the related protocol (ANSI CC), See ‘ANSI CC
Package’. A listing of this header file is provided in ‘xcc_ansi.h’.
- <xcc_gsm_sm.h>
This header file contains specific definitions that reflect the Short Message ITU-T services along
with ASN.1 productions of the related services (ITU-T CC Short Message services), See ‘ITU-T Short
Message Service Package’. A listing of this header file is provided in ‘xcc_gsm_sm.h’.
2.1 C Naming Conventions
The interfaces uses part of the C public namespace for its facilities. All identifiers start with
the letters cc, CC or OCC, and more detail of the conventions used are given in the following
table. Note that the interface reserves all identifiers starting with the letters ccP
for private (i.e. internal) use by implementations of the interface. It also reserves all
identifiers starting with the letters ccX or CCX for vendor-specific extensions of the
interface. Application programmers should not use any identifier starting with these letters.
The OSI-Abstract-Data Manipulation API uses similar, thorugh not identical, naming conventions, that
are described in XOM (reference XOM). All its identifiers are prefixes by the letters OM or
om.
| reserved for implementors | ccP |
| reserved for interface extensions | ccX |
| reserved for interface extensions | CCX |
| reserved for implementors | OCC |
| |
| functions | cc_ |
| error problem values | CC_E_ |
| enumeration tags (except errors) | CC_T_ |
| OM classs names | CC_C_ |
| OM value length limits | CC_VL_ |
| OM value number limits | CC_VN_ |
| other constants | CC_ |
A complete list of all identifiers used (except those beginning ccP, ccX, CCX
or OCC) is given in C Headers. No implementation of the interface will use any other
public identifiers. A public identifier is any name except those reserved in section 4.1.2.1
of the ISO C Standard, and the public namespace is the set of all possible public identifiers.
The C identifiers are derived from the langauage-independent names used throughput this
specification by a purely mechanical process which depends on the kind of name:
2.2 Use and Implementtion of Interfaces
Each of the following statements applies unless explicitly state otherwise in the detailed
descriptions that follow:
If an argument to a function has an invalid value (such as a value outside the domain of the
function, or a pointer outside the address space of the program, or a null pointer), the behvaiour
is undefined.
Any function declared in a header may be implemented as a macro defined in the header, so a library
function should not be declared explicitly if its header is included. Any macro definition of a
function can be suppressed locally be encoding the name of the function in parentheses, because the
name is not then followed by the left parthesis that indicate expansion of a macro function name.
For the same syntactic reason, it is permitted to take the address of a library function even if it
is also defined as a macro. The use of #undef to remove any macro defintion will also
ensure that an actual function is referred to. Any invocation of a library function that is
implemented as a macro will expand to code that evaluates each of its arguments exactly once, fully
protected by parentheses where necessary, so it is generally safe to use arbitrary expressions as
arguments. Likewise, those function-like macros described in the following sections may be invoked
in an expression anywhere a function with a compatible return type could be called.
2.3 Function Return Values
The return value of a C function is always bound to the result of the language-independent
description. Functions return a value of CC_status, which is an error indication. If and
only if the function succeeds, its value will be success, expressed in C by the constant
CC_SUCCESS. If a function returns a status other than this, then it has not updated the
return parameters. The value of the status, in this case, is an error as described in Errors.
In most cases the integer returned in Status is sufficient for error processing. However, in a
few cases additional information is available if desired.
Since C does not provide multiple return values, functions must return all other results by writing
into storage passed by the application program. Any argument that is a pointer to such storage has
a name ending with _return. For example, the C parameter declaration ‘OM_sint
*invoke_id_return’ in the Service-Req() function indicates that the function will return an
signed integer Invoke-Id as a result, so the actual argument to the function must be the address
of a suitable variable. This notation allows the reader to distinguish between an input parameter
that happes to be a pointer, and an output parameter where the * is used to simulate the
semantics of passing by reference.
2.4 Compilation and Linking
All applications programs that use this interface include the <xom.h> and <xcc.h>
headers in that order, and at least one of the <xcc_gsm.h> and <xcc_ansi.h> headers.
3 Description
The interface comprises a number of functions together with many OM classes and OM objects that are
used as the arguments and results of the functions. Both the functions and the OM objects are based
closely on the Abstract Service that is specified in the Standards (references ITU-T ISUP and
ANSI ISUP).
The interface models mobile application interactions as service requests made through a number of
interface functions, which take a number of input arguments. Each valid request causes
an operation within the producer which eventually returns a status and any result
of the operation.
All interactions between a Consumer and a Producer belong to a session, which is represented
by an OM object passed as the first argument to most interface functions.
The other arguments to the function include a context and various service-specific arguments.
The context includes a number of parameters that are common to many functions and that seldom
change from operation to operation.
Each of the components of this model is described below, along with other features of the interface
such as asynchronous function calls and security.
3.1 Services
As mentioned above, the Standards define Abstract Services that Consumers and Producers use.
Each of these Absract Services maps to a single function call with the same name. The services are
Service-req and Service-rsp.
These are three functions called Receive(), Wait(), and Abandon() which have no
counterpart in the Abstract Service. Receive() is used to receive indications and results of
asynchronous operations, and is explained in Interface Functions. Wait() is used to
suspend execution until indications are available for specified sessions. Abandon() is used to
abandon locally the result of a pending asyncrhonous operation. Two additional functions
Bind()2 and Unbind() are used to open and close a user-session.
There are also other interface specific functions called Get-Assoc-Info(), Get-Last-Error(),
Validate-object(), Error-Message(), Initialize(), Shutdown() and Negotiate().
The detailed specifications are given in Interface Functions.
3.1.1 Negotiation Sequence
The interface has an initialize and shutdown sequence that permits the negotiation of optional
features. This involves the functions Initialize(), Negotiate(), and Shutdown().
Every application program must first call Initialize(), that returns a workspace. This
workspace supports only the standard Common ISUP package, See Interface Class Definitions.
The workspace can be extended to support either the ITU-T ISUP or ANSI ISUP package or both (see
Interface Class Definitions, and any combination of the optional Mobile Application Services
packages), or any vendor extensions. Vendor extensions may include additional packages, and may
also include additional or modified functionality. All such packages or other extensions are
identified by means of OSI Object Identifiers, and the Object Identifiers are supplied to the
Negotiate() function to incorporate the extensions into the workspace. Features defined by this
specification are described and assigned Object Identifiers in Interface Functions. A feature
represents any package or any additional or modified functionality that is subject to negotiattion.
The Negotiate() function allows some particular features to be made available.
After a worksapce with the required features has been negotiated in this way, the application can
use the workspace as required. It can create and manipulate OM objects using the OM functions, and
can start one or more management sessions using Bind().3 All the sessions on a given workspace
share the same features.
Eventually, when it has completed its tasks, terminated all is mobile application sessions using
Unbind(), and released all its OM objects using OM-Delete(), the application should ensure
that resources associated with the interface are freed by calling Shutdown().
A miscellaneous error arises if an attempt is made to use an unavailable feature. If an instance of
a class that is not in an available package is supplied as a function argument, the bad-class
error arises.
3.1.2 Names, Addresses and Titles
To address a wide variety of mobile application transport protocols the interface is capable of
accepting various forms of object names, system addresses and program or system titles.
- Name is an “abstract class” that contains various subclass types used to define specific
subscribers or systems responsible for producing mobile application services.
- Address is an “abstract class” that contains various subclass types used to define the
specific location to contact a particular consumer or producer of mobile services. For example, the
SCCP-Address subclass is typically used to define the location of a producer or consumer.
- Title is an “abstract class” that contains various subclass types used to define a
specific subscriber or system name reponsible for producing mobile application services.
All three abstract classes participate in an implementation-specific name resolution scheme. It is
assumed that given a Name, an implementation can determine the Title responsible for that
Name. It is also assumed that given a Title, an implementation can determine the
Address of that Title.4
The producer of an invoked operation may be explicitly designated at the interface boundary using
the following precedence rules:
- A default Title or Address may be supplied as parameters to a bound “session”. If both
are provided, the implementation will verify that the Title resolves to the Address.
- If automatic association management is used, a provider Title or Address may be supplied
as parameters within the “context” or a specific operation request. If both are provided, the
implementation will verify that the Title resolves to the Address. The “context” Title or or
Address takes precedence over the “session” Title or Address for unassociated session objects.
- A consumer address may be supplied as a parameter within the “argument” of a specific
operation request. The “argument” Address takes precedence over either the “session” Title or
Address or the “context” Title or Address.
- If the producer of an invoked operation is not explicitly designated at the interface
boundary, the implementation will resolve the Name to the appropriate Title or Address.
3.2 Session
A session identifies to which mobile application entity a particular operation will be sent. It
contains some Bind-Arguments, such as the name of the consumer. The session is passed as the
first argument to most interface functions.
A session is described by an OM object of OM class Session. It is created, and appropriate
parameter values may be set, using the OSI-Abstract-Data Manipulation functions. A mobile
application session is then started with Bind()5 and later is terminated with Unbind(). A
session with default parameters can be started by passing the constant Default-Session
(‘(OM_object)CC_DEFAULT_SESSION’) as the Session argument to Bind().
Bind() must be called before the Session can be used as an argument to any other function in
the interface. After Unbind() has been called, Bind() must be called again if another
session is to be started.
The interface supports multiple concurrent sessions, so that an application implemented as a single
process, such as a server in a client-server model, can interact with the Mobile Application
Services using several identities; and so that a process can interact directly and concurrently with
different mobile application services.
Detailed specifications of the OM class Session are given in Interface Class Definitions.
A session can be used either acting as a consumer of mobile application services, or acting as a
producer of mobile application services, or both.
A session acn be restricted for use only with a designated program called the responder. When the
responder is omitted and automatic association management is used, the session can be used to
exchange mobile application service information with all processes.
The responder (title and address) parameters of an opened session, if present, specifies the
producer of the requested operation. The precedence rules on address and title of the responder are
described in Names.
Other OM attributes (vendors’ implementation extensions) may be included to specify characteristics
of the underlying protocol used.
There are three type of session objects:
3.2.1 AAM Enabled Session
The Session collects together all the information that described a particular management
interaction. The parameters that are to control such a session are set up in an instance of this OM
class, which is then passed as an argument to Bind().6 This sets the OM attributes that describe
the actual characteristics of the session, and starts the session. Such a started session can be
passed as the first argument to interface functions.
No attribute of a bound or connected session may be changed. The result of modifying a started
session is unspecified.
Finally, Unbind() is used to terminate the sesion, after which the parameters can be modified an
a new session started using the same instance, if required. Multiple concurrent sessions can be
run, by using multiple instances of this OM class.
A session allows a requesting program (the requestor) to exchange mobile application information
with another program designated (the responder) or by default to all programs.
An AAM enabled session thus allows a mobile application entity to access either a portion of
the mobile application services (that is, that are accessible via the designated responder) or all
mobile application services. In the later case, the producer mobile application entity resolution
is performed by the Mobile Application Service provider, according to the mobile application
services invoked.
This type of session object can not be used to receive or send ACSE related primitives or
operations explicitly. The use ACSE explicitly, see AAM Disabled Session.
3.2.2 AAM Disabled Session
A session object can have Automatic Association Management disabled when it belongs to a workspace that has
Automatic Association Management disabled via Negotiate(), which allows the user to explicitly send and
receive ACSE operations to build and tear down associations. It gives explicit control over
associations to the user. The Mobile Application Service provider does no ACSE operations on behalf
of the user.
When the user creates and binds a session object in a workspace with AAM disabled, only the
following attributes within the session object can be specified:
- requestor-Address
- requestor-Title
The session object is then passed as an argument to Bind(),7 which binds
the session. This bound session can only be used to send ACSE related operations an to receive ACSE
related primitives. The following can be sent/received using this type of bound session:
- Receive() (
cc_receive()/‘CC_ASSOC_IND’)
- Receive() (
cc_receive()/‘CC_ASSOC_CNF’)
- Assoc-req() (
cc_assoc_req())
- Assoc-rsp() (
cc_assoc_rsp())
The other attributes that relate to ACSE are specified within an Assoc-Argument or
Assoc-Result object that is passed to, or returned from, Assoc-req(), Assoc-rsp(), or
Receive().
3.2.3 Associated Session
Once a user has created a bound session that has AAM disabled, an association can be created. An
association is represented by an associated or partially associated session object. An
associated session is returned as the result of building a new association. The associated
session is used, like a bound session, by sending and receiving mobile application dialog handling
or service operations. The major difference is that an associated session object can only be used
to send and receive operations to, or from, a single remote mobile application entity. After a
session is associated, the user can abort the association, which implicitly unbinds the associated,
or partialyl associated, session.
The precedence rules for common parameters within the Session and the Context objects are
different for associated session objects. Once a session is in the associated state; the
responder-Address and responder-Title cannot be overridden by the context object.
To terminate this type of session, the user should either abort the session, which implicitly
unbinds the session. If the user unbinds the associated session prior to aborting the association,
the service provider will abort the association.
3.2.4 ADH Enabled Session
The ADH enabled session allows a mobile application entity to invoke and respond to mobile
application services requests and indications without regard for dialog handling. The Mobile
Application Service provider provides all dialog handling.
This type of session cannot be used to send dialog handling primitives or operations explicitly.
To use dialog handling explicitly, see ADH Disabled Session.
3.2.5 ADH Disabled Session
A session object can have Automatic Dialog Handling disabled when it belongs to a workspace that has
Automatic Dialog Handling disabled using the Negotiate() function. This allows the user to
explicitly send and receive dialog handling operations to establish and tear down dialogs. It gives
explicit control over dialogs to the user. The Mobile Application Service provider does no dialog
handling operations on behalf of the user.
Once the session object is bound (AAM enabled) or associated (AAM disabled) and has ADH disabled,
the session must explicitly issue dialog handling operations for each mobile application service
request or response. This bound or associated session can only be used to send dialog handling
primitives. The following can be sent/received using this type of bound or associated session:
- Receive() (
cc_receive()/‘CC_OPEN_IND’)
- Receive() (
cc_receive()/‘CC_ACCEPT_CNF’)
- Receive() (
cc_receive()/‘CC_REFUSE_CNF’)
- Open() (
cc_open())
- Accept() (
cc_accept())
- Refuse() (
cc_refuse())
The other attributes that relate to dialog handling are specified within the Open-Argument,
Accept-Result or Refuse-Result objects that are passed to, or returned from, Open(),
Accept(), Refuse(), or Receive().
3.2.6 Dialog Session
Once a user has created a bound or associated session that has ADH disabled, a dialog can be
created. A dialog is represented by a fully formed, or partially formed dialog,
session object. A dialog session is returned as the result of building a new dialog. The
dialog session is used, like a bound or associated session, by sending and receiving mobile
application service operations. The major difference is that a dialog session object can only be
used to send and receive operations within a single dialog with a single remote mobile application
entity. After a session forms a dialog, the user can close or abort the dialog, which returns the
session to the bound or associated state.
The precedence rules for common parameters within the Session and the Context objects are
different for dialog session objects. Once a session has formed a dialog, the dialog related
arguments, application-Context-Name, cannot be overridden by the context object.
To terminate this type of session, the user should either abort or close the dialog, which
implicitly unbind the session. If the user unbinds the dialog session prior to either closing or
aborting the dialog, the service provider will first attempt to close the dialog, and if that is
rejected, will abort the dialog.
3.3 Context
The context defines the characteristics of the mobile application interaction that are specific to a
particular mobile application operation, but are often used unchanged for many operations. Since
the parameters are presumed to be relatively static for a given user during a particular mobile
application interaction, these arguments are collected into an OM object of OM class Context,
which is supplied as the second argument of each mobile application operation. This serves to
reduce the number of arguments passed to each function.
The context includes various administrative details, such as the mode defined in the Abstract
Service, which affect the processing of each mobile application operation. These include a number
of Service Controls and Local Controls that allow control over some aspects of the
operation.
The Service Controls include
mode, responder-Address, and responder-Title.
The Local Controls include
asynchronous, reply-Limit and time-Limit.
Each of these is mapped onto an OM attribute in the Context, and they are detailed in
Interface Class Definitions.
The effect is as if they were passed as a group of additional arguments on every function call. The
value of each component of the context is determined when the interface function is called, and
remains fixed throughout the operation.
The precedence rules on address and title of the responder are described in Names.
Some of the OM attributes in the Context have default values, some of which are locally
adminstered. The constant Default-Context (‘CC_DEFAULT_CONTEXT’) can be pased as the
value of the Context argument to the interface functions, and has the same effect as a context
OM object created with default values. The context must be a private object, unless it is
Default-Context.
Detailed specifications of the OM class Context are given in Interface Class Definitions.
3.4 Function Arguments
The Abstract Service defines specific arguments for each operation. These are mapped onto
coresponding arguments to each interface function (which are aso called input parameters). Although
each service has different arguments, some specific arguments recur in several operations; these are
briefly introduced here. As far as the ITU-T CC package is concerned, OM classes are defined with a
one-to-one mapping to the ASN.1 Abstract Syntax of ITU-T CC. Full details of these and all the other
arguments are given in the function definitions in Interface Functions, and the OM class
definitions in Interface Class Definitions.
All arguments that are OM objects can generally be supplied to the interface functions as public
objects (i.e, descriptor lists) or as private objects. Private objects must be created in the
workspace that was returned by Initialize(). In some cases, constants can be supplied instead
of OM objects.
Note that wherever a function is stated as accepting an instance of a particular OM class as the
value of an argument, it will also accept an instance of any subclass of that OM class. For
example, the Service-Req function has a parameter argument, which accepts values of OM class
Service-Argument. Any of the subclasses of Service-Argument may be supplied as the value of
argument.
Rules for interpretation of ‘ANY’ syntax appearing in function arguments are defined in
Encoding and Decoding.
3.4.1 Encoding and Decoding
XCC specifies two alternatives for encoding and decoding of Mobile Application Packages
OM-Attribute values of type ‘ANY’, or any OM-Attribute values in a Mobiled Application Services
package.
- The encoding and decoding functionality can be provided internally with the XCC API, without
requiring the application to invoke any encoding or decoding functions. This option allows the
application to be free from any knowledge of encoding rules. In this case, the OM class and
attribute type and corresponding representation are defined in a mobile application or services
package. The XCC API uses the package definition to attempt encoding or decoding; if automatic
decoding fails, an OM String(Encoding) is used.
- The application can perform encoding and decoding itself. This option gives the application
responsibility and control over the encoding and decoding of OM attributes. In this case, all OM
attribute values appear as an OM String(Encoding).
The encoding and decoding alternative to be used is negotiated through the Negotiate() function;
See ‘Negotiate’.
The XCC API does not specify the use of OM-Encode or OM-Decode for the OM classes defined in this
specification, or in mobile application or services packages used with this specification.
To ensure interoperability, the sender and receiver must follow the same encoding rules when
converting between OM syntax and encoded syntax. If an algorithm is used to generate OM packages,
then the algorithm must ensure that the generated OM syntax is consistent with the input abstract
syntax (that is, the same encoded values must result from applying the encoding rules to either
representation). The encoding rules used with the ITU-T CC and ANSI CC packages defined by this
specification are ANS.1 BER. This does not imply that other encoding rules cannot be used with
other packages defined in the future.
For the API to encode and decode the OM attribute values according to the ASN.1 standard scheme,
ASN.1 taggin information must be stored for each OM object and each OM attribute. Thus, the package
definitions in the workspace need to incorporate the ASN.1 tagging information for each OM object
and each OM attribute definition for all Mobile Application Services packages.
As a minimum, the following requirements apply:
- All rules specified in ISO/IEC 8825 – Specification of Basic Encoding Rules for Abstract
Syntax Notation One (ASN.1) shall be adhered to. Any exceptions or restrictions must be stated.
- ASN.1 tagging information must be retained for each OM object and each OM attribute in the
Mobile Application Services packages.
- The specified encoding and decoding scheme (and any implementation thereof) should be
extensible to accomodate the new encoding rules established subsequent to ISO/IEC 8825.
3.4.2 Argument and Response
Most operations and notifications take an argument to specify the argument of the operation and a
response when issuing the response of the operation. These arguments and responses are specified to
accept values of OM classes that are consistent with the abstract service view (ITU-T CC or ANSI CC)
of the current operation.
The argument for a Service-req() function is represented by an instance of the OM Class
ITUT-Service-Req-Argument for a ITU-T CC operation or an instance of the OM Class
ANSI-Service-Req-Argument for an ANSI CC operation.
The reponse for a Service-rsp() function is represented by an instance of the OM Class
GSM-Service-Result, GSM-Linked-Reply-Argument Service-Error or
GSM-Service-Reject to represent the possible responses of the ITU-T service request operation, or
an instance of the ANSI-Service-Result, ANSI-Linked-Reply-Argument Service-Error or
ANSI-Service-Reject to represent the possible responses of the ANSI service request operation.
3.5 Function Results
All functions return a Status (which is the C function result). Most return an Invoke-ID
which identfies the particular invocation. The confirmed operations each return a Result. (The
Invoke-ID and Result are returned using pointers that are supplied as arguments of the C
function). These three kinds of function results are introduced below.
All OM objects returned by interface functions (results and errors) will be private objects in the
workspace assocaited with the session private object.
3.5.1 Invoke-ID
All interface functions that invoke a mobile application service operation return an Invoke-ID;
an integer that identifies the particular invocation of an operation. The Invoke-ID is only
relevant for asynchronous confirmed operations and may be used later to receive the Status and
Result, or to abandon them. The Invoke-ID is also used to respond to a previously requested
confirmed operation. Asynchronous operations are fully described in Synchronous and Asynchronous Operation. The interface functions that can be used to start them are the
Service-req() function.
The numerical value of the invoke-Id returned from a call that successfully invoke an asynchronous
confirmed operation is guaranteed to be unique amoungst all outstanding operations in given session.
The value is such as could be returned from TCAP, the Transaction Capabilities Application Part
defined in ITU-T Recommendation Q.771 through Q.775. Invoke IDs used by XCC are not necessarily
those that are actually sent via a protocol such as TCAP. Invoke IDs may be mapped or altered by
the Mobile Application Service provider.
The value returned for a synchronous operation or an asynchronous non-confirmed operation is
unspecified, as is that for a call that fails to invoke an operation.
3.5.2 Result
Functions invoking confirmed mobile application service operations return a result only if they
succeed. All errors from these functions are reported in the Status described below, as are
errors from all other functions.
The value returned by a function call that invokes an asynchronous operation is unspecified, as is
that for a call that fails to invoke an operation. The result of an asynchronous operation is
returned by a later call to Receive().
The result of a function invoking a confirmed operation can be composed of a single reply, or of
multiple linked replies. In the later case, the term partial result is used to designate one
of these linked replies. Only a confirmed Service-req may produce multiple results. Multiple
replies to a single mobile application service operation may only occur if the invoker specifies
multiple-reply in the functional unit attribute of the Session object.
In asynchronous mode, the partial results can be retrieved one at a time by subsequent calls to
Receive(), which each time returns an instance of OM class Linked-Reply-Argument. In
synchronous mode, the function returns an instance of OM class Multiple-Reply, which contains a
list of sub-objects of OM class Linked-Reply-Argument.
The result (or partial result) of an operation is returned in a private object whose OM class is
appropriate to the particular operation. The format of mobile application service operation results
is driven both by the Abstract Service and by the need to provide asynchronous execution of
functions. To simplify processing of asynchronous results, the result (or partial result) of a
single operation is returned in a single OM obejct (corresponding to the abstract result defined in
the Standards). The components of the result (or partial result) of an operation are represented by
OM attribute in the operation’s result object. All information contianed in the Abstract Service
result is made available to the application program. The result (partial result) is inspected using
the functions provided in the OSI-Abstract-Data Manipulation API.
Only confirmed mobile application service operations produce results, and each type of operation has
a specific OM class of OM object for its result. These OM classes are defined in Interface Class Definitions.
The actual OM class of the result can always be a subclass of that named, to allow flexibility for
extensions. Thus, the function OM-Instance() should always be used when testing the OM class.
3.5.3 Status
Every interface function returnes a Status value, which is either the constant success
(‘(CC_status)0’ or ‘CC_SUCCESS’) or an error. Function call errors are represented as
integer constants and grouped in categories of System, Library and Communications as described in
Errors.
Additional error information is available for System and Communications errors via the
Get-Last-Error() function call. Additional error information is available for the
bad-argument Library error via the Validate-object() function call.
A synchronous call with multiple linked replies is considered successful unless the reploy limit or
time limit is exceeded. The function returns a Status value equal to success, and the argument
Result is an OM object of OM class Multiple-Reply, which contains all the linked replies.
It should be noted that OM object Linked-Reply-Argument may contain an OM attribute that
reflects an error.
If the reply limit or time limit is exceeded, the synchronous call fails and returns a status of the
appropriate Library error. However, the Result is still considered valid and may contain an
OM-Object Multiple-Reply, which contains all the received linked replies. A result of
CC_ABSENT_OBJECT means no replies were received.
In most cases other results of functions are initialized to Null (CC_ABSENT_OBJECT) if the
status does not have the value success. However, the Result is still considered valid and
may contain an OM-Object of parital replies. A result of CC_ABSENT_OBJECT means no replies
were received.
3.6 Synchronous and Asynchronous Operation
The asynchronous or synchronous mode of a requested operation is specified at the interface, and
determined for each operation by the value of the OM attribute Asynchronous in the Context
passed to the interface function. The default value of this OM attribute is false, causing all
operations to by synchronous. Support for both synchronous and asynchronous operation is mandatory.
There is a limit to the number of pending asynchronous operations; this limit is given by the
constant max-outstanding-operations, and has a minimum value of 10.
In synchronous mode, all functions wait until the operation is complete before returning. Thus the
thread of control is blocked within the interface after calling a function, and the application can
make use of the result immediately after the function returns.
In asynchronous mode, some functions return before the operation is complete. The application is
then able to continue with other processing while the operation is being executed by the Mobile
Application Service provider, and can then access the result by calling Receive(). An
application may initiate several concurrent asynchronous operations on the ame session before
receiving any of the results, subject to the limit described below. The results are not guaranteed
to be returned in any particular order. The functions that can execute asynchronously are the
Service-req() function. This correponds to the mobile application services of the Standards
that operate in a confirmed mode. Moreover, only confirmed operations return service results.
An asynchronous function call of a confirmed service returns an Invoke-ID of the operation to
the application. The same Invoke-ID will be returned by Receive() on the corresponding
result.
An Invoke-ID is also returned by Receive() on an indication of an invoked mobile application
service operation. The same Invoke-ID will be used to respond to this operation.
Implementations of the interface are free to return from asynchronous function calls as soon as
possible or may wait until the operation has been submitted to the unerlying Mobile Application
Service provider. The actual policy used is implemetnation-defined.
Implementations will define a limit to the number of asyncrhonous operations that may be outstanding
at any one time on any one session. An asynchronous operation is outstanding from the time that the
function is called until the last reply of the result is returned by Receive(), or the operation
is abandoned by Abandon(), or the session is closed by Unbind(). The limit is given by the
constant max-outstanding-operations (‘CC_MAX_OUTSTANDING_OPERATIONS’) and is at least 10
for conformant XCC implemetnations. While this number of operations is outstanding, attempts to
invoke further asynchronous operations will report a Library-Error (too many operations).
Asynchronous operation calls can be aborted by executing an Abandon() or Unbind() call. In
this case, the operation is no longer outstanding and the result will never be returned by further
Receive() function calls.
If an error is detected before an asynchronous request is submitted to the Mobile Application
Service provider, the function will return immediately and there will be no outstanding operation
generated. Other errors are notified later by Receive(), when the result of the outstanding
asynchronous confirmed operation is returned. All errors occurring during a synchronous request are
reported when the function returns. Full details of error handling are given in Errors.
Where vendors provide suitable system primitives (such as System V poll(2s), or BSD
select(2)), applications can obtain a file descriptor from the Session by inspecting
the value fo the OM attribute File-Descriptor. Applications may use the file descriptor to
suspend the process until data is received on the particular file descriptor.
Applications should ensure that there are no outstanding asynchronous operations on a session when
Unbind() is called on that session. Once Unbind() has been called there is no way to
determine whether any outstanding operations succeed or even whether they were ever sent to the
Mobile Application Service provider. Also no errors or results of any kind will be reported to the
application. It is strongly recommended that Receive() is called repeatedly until
Completion-Flag takes the value nothing.
3.7 Other Features
These features are not part of the interface itself, but are mandatory when specified by the Mobile
Application Service provider.
The Mobile Applications are not restricted to those defined by ITU-T CC.
All the features listed below are for the most part necessary for ease of use in a mobile
application environment. These features are classified as given registered identifiers (Object
Identifier). They can be negotiated using the Negotiate() function in the same manner as
packages. Other types of information that are critical in servicing an environment that incudes
implemetnation from multiple vendors on various machines can also be classified and handled with
the Negotiate() function. Features defined by this specification are described and assigned
Object Identifiers in Interface Functions.
3.7.1 Automatic Association Management
When the Mobile Application Services provider makes use of association oriented communication services,
such as TCAP, the Mobile Application Service provider implementations are assumed to provide
automatic handling of the association between mobile application entities, establishing
and releasing associations at its discretion. Such management is intended to bring
benefits such as reduced communication charges. To allow this flexibility to the implementation,
the interface does not specify when communication takes place. Automatic Association Management
(AAM) may be enabled or disabled on a per-workspace basis using the Negotiate() function.
3.7.2 Automatic Dialog Handling
When the Mobile Application Services provider makes use of dialog oriented communication services,
such as that provided by TCAP, the Mobile Application Service provider implementations are assumed
to provide automatic handling of dialogs between mobile application entities, establishing and
releasing dialogs at its discretion. Such management is intended to bring benefits such as reduced
communication overheads. To allow this flexibility to the implementation, the interface does not
specify when communication takes place. Automatic Dialog Handling (ADH) may be enabled or disabled
on a per-workspace basis using the Negotiate() function.8
3.7.3 Automatic Performer Resolution
The performer of an invoked operation my be explicitly designated by the responder name and
responder address parameters of the bound session used.
However, in the case where the responder is specified as a wildcard, the Mobile Application Service
provider may be assumed to provide automatic mobile application service and application context to
consumer resolution: to find out the consumer that is in charge of the selected mobile application
service specified in the mobile application service operation.
3.7.4 Responder Versatility
Responder versatility is the ability to change the consumer within a same bound-session at each
function call. It is useful when the automatic consumer resolution is either not suported by the
Mobile Application Service provider or note requested. This applies if the underlying Mobile
Application Service provider is connection-less.
3.7.5 Automatic Name to Address Resolution
Mobile Application Service provider implementation may provide automatic resolution between program
name and address to find the network address of a mobile application entity from its name using
directory or translation services.
3.7.6 Automatic Dispatching to Appropriate Stack
The Mobile Application Services provideer implementation may provide a loop back facility if the
destination of the operation or notification is local. It also may provide routing of the
mobile application services operation to the proper underlying communications stack according to the
implied mobile application service and the destination (for example over a ITU-T SCCP stack or an
ANSI SCCP stack).
3.8 Function Sequencing
A minimum set of sequencing rules applies when using the interface to exchange mobile application
service information between mobile application programs acting as a mobile application entity.
These rules need to be respected by mobile application programs to ensure that interface
functions are called in the proper sequence and that the state of the interface is not violated,
otherwise Library-error status will be returned.9
The general rules to follow are:
- Initialize a workspace (‘cc_initialize()’)
- Negotiate features of the interface (‘cc_negotiate()’)
- Open one or several sessions (‘cc_bind()’)
- Perform mobile application service interactions (operations) using the offered interface
functions. An interaction is identified by its Invoke-Id.
- Close the opened sessions (‘cc_unbind()’)
- Discard the workspace (‘cc_shutdown()’)
Seven states are defined in the interface to cover both interface service operations and mobile
application service interactions:
- UNINIT
Workspace uninitialized.
- INIT
Workspace initialized.
- UNBND
Session closed.
- BND
Session opened.
- IDLE
Outstanding operatoin requested in a mobile application service interaction.
- OUTOP
Operation indication received in a mobile application service interaction.
- OPIND
4 Interface Functions
5 Interface Class Definitions
6 Errors
Appendix A C Headers
A.1 xcc.h
A.2 xcc_isup.h
A.3 xcc_isdn.h
A.4 xcc_h323.h
A.5 xcc_sipt.h
Appendix B Examples
Glossary
Licenses
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GNU Affero General Public License
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When you convey a covered work, you waive any legal power to forbid
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You may convey verbatim copies of the Program’s source code as you
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and you may offer support or warranty protection for a fee.
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- Convey the object code using peer-to-peer transmission, provided you
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included in conveying the object code work.
A “User Product” is either (1) a “consumer product”, which means any
tangible personal property which is normally used for personal,
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If you convey an object code work under this section in, or with, or
specifically for use in, a User Product, and the conveying occurs as
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by the Installation Information. But this requirement does not apply
if neither you nor any third party retains the ability to install
modified object code on the User Product (for example, the work has
been installed in ROM).
The requirement to provide Installation Information does not include a
requirement to continue to provide support service, warranty, or
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recipient, or for the User Product in which it has been modified or
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- Additional Terms.
“Additional permissions” are terms that supplement the terms of this
License by making exceptions from one or more of its conditions.
Additional permissions that are applicable to the entire Program shall
be treated as though they were included in this License, to the extent
that they are valid under applicable law. If additional permissions
apply only to part of the Program, that part may be used separately
under those permissions, but the entire Program remains governed by
this License without regard to the additional permissions.
When you convey a copy of a covered work, you may at your option
remove any additional permissions from that copy, or from any part of
it. (Additional permissions may be written to require their own
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Notwithstanding any other provision of this License, for material you
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All other non-permissive additional terms are considered “further
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received it, or any part of it, contains a notice stating that it is
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a further restriction but permits relicensing or conveying under this
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Additional terms, permissive or non-permissive, may be stated in the
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above requirements apply either way.
- Termination.
You may not propagate or modify a covered work except as expressly
provided under this License. Any attempt otherwise to propagate or
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this License (including any patent licenses granted under the third
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However, if you cease all violation of this License, then your license
from a particular copyright holder is reinstated (a) provisionally,
unless and until the copyright holder explicitly and finally
terminates your license, and (b) permanently, if the copyright holder
fails to notify you of the violation by some reasonable means prior to
60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.
Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License. If your rights have been terminated and not permanently
reinstated, you do not qualify to receive new licenses for the same
material under section 10.
- Acceptance Not Required for Having Copies.
You are not required to accept this License in order to receive or run
a copy of the Program. Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer transmission
to receive a copy likewise does not require acceptance. However,
nothing other than this License grants you permission to propagate or
modify any covered work. These actions infringe copyright if you do
not accept this License. Therefore, by modifying or propagating a
covered work, you indicate your acceptance of this License to do so.
- Automatic Licensing of Downstream Recipients.
Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License. You are not responsible
for enforcing compliance by third parties with this License.
An “entity transaction” is a transaction transferring control of an
organization, or substantially all assets of one, or subdividing an
organization, or merging organizations. If propagation of a covered
work results from an entity transaction, each party to that
transaction who receives a copy of the work also receives whatever
licenses to the work the party’s predecessor in interest had or could
give under the previous paragraph, plus a right to possession of the
Corresponding Source of the work from the predecessor in interest, if
the predecessor has it or can get it with reasonable efforts.
You may not impose any further restrictions on the exercise of the
rights granted or affirmed under this License. For example, you may
not impose a license fee, royalty, or other charge for exercise of
rights granted under this License, and you may not initiate litigation
(including a cross-claim or counterclaim in a lawsuit) alleging that
any patent claim is infringed by making, using, selling, offering for
sale, or importing the Program or any portion of it.
- Patents.
A “contributor” is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based. The
work thus licensed is called the contributor’s “contributor version”.
A contributor’s “essential patent claims” are all patent claims owned
or controlled by the contributor, whether already acquired or
hereafter acquired, that would be infringed by some manner, permitted
by this License, of making, using, or selling its contributor version,
but do not include claims that would be infringed only as a
consequence of further modification of the contributor version. For
purposes of this definition, “control” includes the right to grant
patent sublicenses in a manner consistent with the requirements of
this License.
Each contributor grants you a non-exclusive, worldwide, royalty-free
patent license under the contributor’s essential patent claims, to
make, use, sell, offer for sale, import and otherwise run, modify and
propagate the contents of its contributor version.
In the following three paragraphs, a “patent license” is any express
agreement or commitment, however denominated, not to enforce a patent
(such as an express permission to practice a patent or covenant not to
sue for patent infringement). To “grant” such a patent license to a
party means to make such an agreement or commitment not to enforce a
patent against the party.
If you convey a covered work, knowingly relying on a patent license,
and the Corresponding Source of the work is not available for anyone
to copy, free of charge and under the terms of this License, through a
publicly available network server or other readily accessible means,
then you must either (1) cause the Corresponding Source to be so
available, or (2) arrange to deprive yourself of the benefit of the
patent license for this particular work, or (3) arrange, in a manner
consistent with the requirements of this License, to extend the patent
license to downstream recipients. “Knowingly relying” means you have
actual knowledge that, but for the patent license, your conveying the
covered work in a country, or your recipient’s use of the covered work
in a country, would infringe one or more identifiable patents in that
country that you have reason to believe are valid.
If, pursuant to or in connection with a single transaction or
arrangement, you convey, or propagate by procuring conveyance of, a
covered work, and grant a patent license to some of the parties
receiving the covered work authorizing them to use, propagate, modify
or convey a specific copy of the covered work, then the patent license
you grant is automatically extended to all recipients of the covered
work and works based on it.
A patent license is “discriminatory” if it does not include within the
scope of its coverage, prohibits the exercise of, or is conditioned on
the non-exercise of one or more of the rights that are specifically
granted under this License. You may not convey a covered work if you
are a party to an arrangement with a third party that is in the
business of distributing software, under which you make payment to the
third party based on the extent of your activity of conveying the
work, and under which the third party grants, to any of the parties
who would receive the covered work from you, a discriminatory patent
license (a) in connection with copies of the covered work conveyed by
you (or copies made from those copies), or (b) primarily for and in
connection with specific products or compilations that contain the
covered work, unless you entered into that arrangement, or that patent
license was granted, prior to 28 March 2007.
Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.
- No Surrender of Others’ Freedom.
If conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License. If you cannot convey
a covered work so as to satisfy simultaneously your obligations under
this License and any other pertinent obligations, then as a
consequence you may not convey it at all. For example, if you agree
to terms that obligate you to collect a royalty for further conveying
from those to whom you convey the Program, the only way you could
satisfy both those terms and this License would be to refrain entirely
from conveying the Program.
- Remote Network Interaction; Use with the GNU General Public License.
Notwithstanding any other provision of this License, if you modify the
Program, your modified version must prominently offer all users interacting
with it remotely through a network (if your version supports such
interaction) an opportunity to receive the Corresponding Source of your
version by providing access to the Corresponding Source from a network
server at no charge, through some standard or customary means of
facilitating copying of software. This Corresponding Source shall include
the Corresponding Source for any work covered by version 3 of the GNU
General Public License that is incorporated pursuant to the following
paragraph.
Notwithstanding any other provision of this License, you have permission to
link or combine any covered work with a work licensed under version 3 of
the GNU General Public License into a single combined work, and to convey
the resulting work. The terms of this License will continue to apply to
the part which is the covered work, but the work with which it is combined
will remain governed by version 3 of the GNU General Public License.
- Revised Versions of this License.
The Free Software Foundation may publish revised and/or new versions
of the GNU Affero General Public License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the Program
specifies that a certain numbered version of the GNU Affero General Public
License “or any later version” applies to it, you have the option of
following the terms and conditions either of that numbered version or
of any later version published by the Free Software Foundation. If
the Program does not specify a version number of the GNU Affero General
Public License, you may choose any version ever published by the Free
Software Foundation.
If the Program specifies that a proxy can decide which future versions
of the GNU Affero General Public License can be used, that proxy’s public
statement of acceptance of a version permanently authorizes you to
choose that version for the Program.
Later license versions may give you additional or different
permissions. However, no additional obligations are imposed on any
author or copyright holder as a result of your choosing to follow a
later version.
- Disclaimer of Warranty.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT
WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND
PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE
DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR
CORRECTION.
- Limitation of Liability.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR
CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES
ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT
NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR
LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM
TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER
PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
- Interpretation of Sections 15 and 16.
If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.
END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these
terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the “copyright” line and a pointer to where the full notice is found.
one line to give the program's name and a brief idea of what it does.
Copyright (C) year name of author
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see http://www.gnu.org/licenses/.
Also add information on how to contact you by electronic and paper mail.
If your software can interact with users remotely through a
network, you should also make sure that it provides a way for users to
get its source. For example, if your program is a web application, its
interface could display a “Source” link that leads users to an archive
of the code. There are many ways you could offer source, and different
solutions will be better for different programs; see section 13 for the
specific requirements.
You should also get your employer (if you work as a programmer) or school,
if any, to sign a “copyright disclaimer” for the program, if necessary.
For more information on this, and how to apply and follow the GNU AGPL, see
http://www.gnu.org/licenses/.
GNU Free Documentation License
GNU FREE DOCUMENTATION LICENSE
Version 1.3, 3 November 2008
Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
http://fsf.org/
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
- PREAMBLE
The purpose of this License is to make a manual, textbook, or other
functional and useful document free in the sense of freedom: to assure everyone
the effective freedom to copy and redistribute it, with or without
modifying it, either commercially or noncommercially. Secondarily,
this License preserves for the author and publisher a way to get
credit for their work, while not being considered responsible for
modifications made by others.
This License is a kind of “copyleft”, which means that derivative
works of the document must themselves be free in the same sense. It
complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does. But this License is not limited to software manuals;
it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book. We recommend this License
principally for works whose purpose is instruction or reference.
- APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium, that contains a
notice placed by the copyright holder saying it can be distributed
under the terms of this License.
Such a notice grants a world-wide, royalty-free license, unlimited in
duration, to use that work under the conditions stated herein.
The “Document”, below, refers to any
such manual or work. Any member of the public is a licensee, and is
addressed as “you”.
You accept the license if you copy, modify or distribute the work in a
way requiring permission under copyright law.
A “Modified Version” of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
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A “Secondary Section” is a named appendix or a front-matter section of
the Document that deals exclusively with the relationship of the
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mathematics.) The relationship could be a matter of historical
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commercial, philosophical, ethical or political position regarding
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The “Invariant Sections” are certain Secondary Sections whose titles
are designated, as being those of Invariant Sections, in the notice
that says that the Document is released under this License.
If a section does not fit the above definition of Secondary then it is
not allowed to be designated as Invariant. The Document may contain
zero Invariant Sections. If the Document does not identify any
Invariant Sections then there are none.
The “Cover Texts” are certain short passages of text that are listed,
as Front-Cover Texts or Back-Cover Texts, in the notice that says that
the Document is released under this License.
A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be
at most 25 words.
A “Transparent” copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
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drawing editor, and that is suitable for input to text formatters or
for automatic translation to a variety of formats suitable for input
to text formatters. A copy made in an otherwise Transparent file
format whose markup, or absence of markup, has been arranged to thwart or discourage
subsequent modification by readers is not Transparent. An image format
is not Transparent if used for any substantial amount of text. A copy
that is not “Transparent” is called “Opaque”.
Examples of suitable formats for Transparent copies include plain
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or PDF designed for human modification. Examples of
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read and edited only by proprietary word processors, SGML or
XML for which the DTD and/or processing tools are
not generally available, and the machine-generated HTML,
PostScript or PDF produced by some word processors for output
purposes only.
The “Title Page” means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the material
this License requires to appear in the title page. For works in
formats which do not have any title page as such, “Title Page” means
the text near the most prominent appearance of the work’s title,
preceding the beginning of the body of the text.
The “publisher” means any person or entity that distributes copies of
the Document to the public.
A section “Entitled XYZ” means a named subunit of the Document whose
title either is precisely XYZ or contains XYZ in parentheses following
text that translates XYZ in another language. (Here XYZ stands for a
specific section name mentioned below, such as “Acknowledgements”,
“Dedications”, “Endorsements”, or “History”.) To “Preserve the
Title” of such a section when you modify the Document means that it
remains a section “Entitled XYZ” according to this definition.
The Document may include Warranty Disclaimers next to the notice which
states that this License applies to the Document. These Warranty
Disclaimers are considered to be included by reference in this License,
but only as regards disclaiming warranties: any other implication that
these Warranty Disclaimers may have is void and has no effect on the
meaning of this License.
- VERBATIM COPYING
You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies
to the Document are reproduced in all copies, and that you add no other
conditions whatsoever to those of this License. You may not use
technical measures to obstruct or control the reading or further
copying of the copies you make or distribute. However, you may accept
compensation in exchange for copies. If you distribute a large enough
number of copies you must also follow the conditions in section 3.
You may also lend copies, under the same conditions stated above, and
you may publicly display copies.
- COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly have
printed covers) of the Document, numbering more than 100, and the
Document’s license notice requires Cover Texts, you must enclose the
copies in covers that carry, clearly and legibly, all these Cover
Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
the back cover. Both covers must also clearly and legibly identify
you as the publisher of these copies. The front cover must present
the full title with all words of the title equally prominent and
visible. You may add other material on the covers in addition.
Copying with changes limited to the covers, as long as they preserve
the title of the Document and satisfy these conditions, can be treated
as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto adjacent
pages.
If you publish or distribute Opaque copies of the Document numbering
more than 100, you must either include a machine-readable Transparent
copy along with each Opaque copy, or state in or with each Opaque copy
a computer-network location from which the general network-using
public has access to download using public-standard network protocols
a complete
Transparent copy of the Document, free of added material. If you use the latter
option, you must take reasonably prudent steps, when you begin
distribution of Opaque copies in quantity, to ensure that this
Transparent copy will remain thus accessible at the stated location
until at least one year after the last time you distribute an Opaque
copy (directly or through your agents or retailers) of that edition to
the public.
It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to give
them a chance to provide you with an updated version of the Document.
- MODIFICATIONS
You may copy and distribute a Modified Version of the Document under
the conditions of sections 2 and 3 above, provided that you release
the Modified Version under precisely this License, with the Modified
Version filling the role of the Document, thus licensing distribution
and modification of the Modified Version to whoever possesses a copy
of it. In addition, you must do these things in the Modified Version:
- Use in the Title Page (and on the covers, if any) a title distinct
from that of the Document, and from those of previous versions
(which should, if there were any, be listed in the History section
of the Document). You may use the same title as a previous version
if the original publisher of that version gives permission.
- List on the Title Page, as authors, one or more persons or entities
responsible for authorship of the modifications in the Modified
Version, together with at least five of the principal authors of the
Document (all of its principal authors, if it has fewer than five),
unless they release you from this requirement.
- State on the Title page the name of the publisher of the
Modified Version, as the publisher.
- Preserve all the copyright notices of the Document.
- Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
- Include, immediately after the copyright notices, a license notice
giving the public permission to use the Modified Version under the
terms of this License, in the form shown in the Addendum below.
- Preserve in that license notice the full lists of Invariant Sections
and required Cover Texts given in the Document’s license notice.
- Include an unaltered copy of this License.
- Preserve the section Entitled “History”, Preserve its Title, and add to
it an item stating at least the title, year, new authors, and
publisher of the Modified Version as given on the Title Page. If
there is no section Entitled “History” in the Document, create one
stating the title, year, authors, and publisher of the Document as
given on its Title Page, then add an item describing the Modified
Version as stated in the previous sentence.
- Preserve the network location, if any, given in the Document for
public access to a Transparent copy of the Document, and likewise
the network locations given in the Document for previous versions
it was based on. These may be placed in the “History” section.
You may omit a network location for a work that was published at
least four years before the Document itself, or if the original
publisher of the version it refers to gives permission.
- For any section Entitled “Acknowledgements” or “Dedications”,
Preserve the Title of the section, and preserve in the section all the
substance and tone of each of the contributor acknowledgements
and/or dedications given therein.
- Preserve all the Invariant Sections of the Document,
unaltered in their text and in their titles. Section numbers
or the equivalent are not considered part of the section titles.
- Delete any section Entitled “Endorsements”. Such a section
may not be included in the Modified Version.
- Do not retitle any existing section to be Entitled “Endorsements”
or to conflict in title with any Invariant Section.
- Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no material
copied from the Document, you may at your option designate some or all
of these sections as invariant. To do this, add their titles to the
list of Invariant Sections in the Modified Version’s license notice.
These titles must be distinct from any other section titles.
You may add a section Entitled “Endorsements”, provided it contains
nothing but endorsements of your Modified Version by various
parties—for example, statements of peer review or that the text has
been approved by an organization as the authoritative definition of a
standard.
You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list
of Cover Texts in the Modified Version. Only one passage of
Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity. If the Document already
includes a cover text for the same cover, previously added by you or
by arrangement made by the same entity you are acting on behalf of,
you may not add another; but you may replace the old one, on explicit
permission from the previous publisher that added the old one.
The author(s) and publisher(s) of the Document do not by this License
give permission to use their names for publicity for or to assert or
imply endorsement of any Modified Version.
- COMBINING DOCUMENTS
You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and
list them all as Invariant Sections of your combined work in its
license notice, and that you preserve all their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name but
different contents, make the title of each such section unique by
adding at the end of it, in parentheses, the name of the original
author or publisher of that section if known, or else a unique number.
Make the same adjustment to the section titles in the list of
Invariant Sections in the license notice of the combined work.
In the combination, you must combine any sections Entitled “History”
in the various original documents, forming one section Entitled
“History”; likewise combine any sections Entitled “Acknowledgements”,
and any sections Entitled “Dedications”. You must delete all sections
Entitled “Endorsements.”
- COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other documents
released under this License, and replace the individual copies of this
License in the various documents with a single copy that is included in
the collection, provided that you follow the rules of this License for
verbatim copying of each of the documents in all other respects.
You may extract a single document from such a collection, and distribute
it individually under this License, provided you insert a copy of this
License into the extracted document, and follow this License in all
other respects regarding verbatim copying of that document.
- AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other separate
and independent documents or works, in or on a volume of a storage or
distribution medium, is called an “aggregate” if the copyright
resulting from the compilation is not used to limit the legal rights
of the compilation’s users beyond what the individual works permit.
When the Document is included in an aggregate, this License does not
apply to the other works in the aggregate which
are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half
of the entire aggregate, the Document’s Cover Texts may be placed on
covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic form.
Otherwise they must appear on printed covers that bracket the whole
aggregate.
- TRANSLATION
Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section 4.
Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also include
the original English version of this License and the original versions
of those notices and disclaimers. In case of a disagreement
between the translation and the original version of this
License or a notice or disclaimer, the original version will prevail.
If a section in the Document is Entitled “Acknowledgements”,
“Dedications”, or “History”, the requirement (section 4) to Preserve
its Title (section 1) will typically require changing the actual
title.
- TERMINATION
You may not copy, modify, sublicense, or distribute the Document except
as expressly provided under this License. Any attempt otherwise to
copy, modify, sublicense, or distribute it is void, and will
automatically terminate your rights under this License.
However, if you cease all violation of this License, then your license
from a particular copyright holder is reinstated (a) provisionally,
unless and until the copyright holder explicitly and finally terminates
your license, and (b) permanently, if the copyright holder fails to
notify you of the violation by some reasonable means prior to 60 days
after the cessation.
Moreover, your license from a particular copyright holder is reinstated
permanently if the copyright holder notifies you of the violation by
some reasonable means, this is the first time you have received notice
of violation of this License (for any work) from that copyright holder,
and you cure the violation prior to 30 days after your receipt of the
notice.
Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License. If your rights have been terminated and not permanently
reinstated, receipt of a copy of some or all of the same material does
not give you any rights to use it.
- FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions
of the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
http://www.gnu.org/copyleft/.
Each version of the License is given a distinguishing version number.
If the Document specifies that a particular numbered version of this
License “or any later version” applies to it, you have the option of
following the terms and conditions either of that specified version or
of any later version that has been published (not as a draft) by the
Free Software Foundation. If the Document does not specify a version
number of this License, you may choose any version ever published (not
as a draft) by the Free Software Foundation.
If the Document specifies that a proxy can decide which future versions
of this License can be used, that proxy’s public statement of acceptance
of a version permanently authorizes you to choose that version for the
Document.
- RELICENSING
“Massive Multiauthor Collaboration Site” (or “MMC Site”) means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works. A public
wiki that anybody can edit is an example of such a server. A “Massive
Multiauthor Collaboration” (or “MMC”) contained in the site means any
set of copyrightable works thus published on the MMC site.
“CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.
“Incorporate” means to publish or republish a Document, in whole or in
part, as part of another Document.
An MMC is “eligible for relicensing” if it is licensed under this
License, and if all works that were first published under this License
somewhere other than this MMC, and subsequently incorporated in whole or
in part into the MMC, (1) had no cover texts or invariant sections, and
(2) were thus incorporated prior to November 1, 2008.
The operator of an MMC Site may republish an MMC contained in the site
under CC-BY-SA on the same site at any time before August 1, 2009,
provided the MMC is eligible for relicensing.
ADDENDUM: How to use this License for your documents
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:
Copyright (C) year your name.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the “with…Texts.” line with this:
with the Invariant Sections being list their titles, with
the Front-Cover Texts being list, and with the Back-Cover Texts
being list.
If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.
If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License,
to permit their use in free software.
Index
Short Table of Contents
Table of Contents