Author image Stanislav Sinyagin
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SIAM::Documentation::DataModel - SIAM data model in details


SIAM (Service Inventory Abstraction Model) is intended as a common API that would connect to enterprise-specific service inventory systems and present the inventory data in a uniform format. The purpose of this universal API is to reduce the integration costs for such software systems as network monitoring, CRM, Customer self-service portals, etc.



Each object is defined by a set of attributes. Some attributes are mandatory for a particular object class.

Each pair of objects may or may not be in contained/container relationship. Any single object may only be contained in one container.

Visibility of attributes and their values is defined by Access Scope associated with a particular client user.

Attribute names starting with the prefix siam.* are reserved solely for SIAM use.

In boolean attributes, numerical zero is interpreted as "false", and numerical nonzero is treated as "true". Usually numerical 1 indicates a true value.

Some attributes contain identifiers of other objects. The string value NIL is reserved to indicate an undefined identifier.

Attribute values are strings in UTF-8 encoding. The client software should treat UTF-8 correctly, especially where it deals with names and addresses.

Some objects may also define computables. A computable is a special attribute which requires substantial CPU time to derive its value. Computables are not retrieved automatically among other attributes, and are only delivered via explicit method calls. In case if the underlying driver does not support a particular computable, it should return an empty string.

The driver may define conditions for some objects. A condition is a (key, value) pair that the SIAM client application sends towards the driver. This is a one-way communication: there is no direct access to the condition value, and the driver is free to do anything with it or ignore it. Usually drivers update some internal state databases upin receiveing a new condition.

In this document, XYZ refers to the enterprise name.


All SIAM object classes (including the root-level SIAM class) are derived from SIAM::Object class. The following attributes are mandatory for every object:


    The attribute defines a unique identifier for the object. Client applications must not set any assumptions on the ID values or their structure. The back-end drivers generate the ID values, and these values are only meaningful within the driver data model. Maximum length: 1024 bytes. The identifiers starting with the string SIAM. are reserved to the SIAM internals and must not be used by the drivers.

  • siam.object.class

    The full Perl package name of the object, such as SIAM::ServiceUnit. The back-end drivers should rely on these values in their internal logics. The drivers should be flexible enough to accept new object classes without breaking the logics.

  • siam.object.complete

    The attribute should return true value when it's completely ready to use. For example, a Service Data Element object may not be ready to deliver the data because the underlying system has not yet prepared it. In this case, this attribute would return false value. If the driver does not deliver a value for this attribute, SIAM::Object sets it to true.

  • siam.object.container

    The attribute refers to the containing object's ID or is set to NIL.

  • siam.object.has_reports

    This attribute returns a true value if one or more reports is associated with it. Reports are usually performed on the underlying contained objects. If the driver does not deliver a value for this attribute, SIAM::Object sets it to false.

The following object IDs are predefined by SIAM and are not queried via the driver:


    The root-level object.


    The access scope with the name AllContracts. All contract objects are implicitly included in it.


    The access scope with the name AllAttributes. All attribute names are implicitly in it.

Root object

The root object of class SIAM is the only object in the hierarchy that is not retrieved from the back-end driver. The root object has no attributes.


The enterprise billing system would usually work with contracts. Contracts consist of services.

Mandatory attributes:

  • siam.contract.inventory_id

    Contract identifier in external inventory. This should refer to the contract number as seen in the enterprise billing system.

  • siam.contract.customer_name

    String identifying the contract holder name

  • siam.contract.customer_id

    Contract holder ID in the external inventory


  • siam.contract.content_md5hash

    Returns a hex string representing the MD5 hash of all the objects related to this contract. The client application may use this value as an indicator if it has to refresh its internal cache.

Attribute examples:

  • xyz.is_suspended, xyz.billing_ok, xyz.reseller_id

    These define the internal logic which is specific to particular SIAM use.


A Service is a billing unit within the enterprise. It consists of Service Units.

For example, a WAN connectivity service would consist of one Service object, consisting of a Service Unit object per location, and one or two Service Component objects per Unit for single and redundant physical links.

Mandatory attributes:

  • siam.svc.product_name

    A name from the enterprise's product catalog.

  • siam.svc.type

    A string from a limited dictionary of predefined service types. It refers to a service template which identifies the attributes which are required for each service type.

  • siam.svc.inventory_id

    Service ID in external inventory, such as the billing system.

Attribute examples:

  •,, xyz.svc.street

    Location information for a service.


Service Unit is an elementary logical entity that builds up a service. For example, for a redundant WAN connection, a Service Unit would correspond to one WAN location, and it would consist of two Service Components for each link.

A ServiceUnit consists of service options, such as access speed, hosting disk size, etc. The corresponding Service Component has implementation attributes, such as link identifier, access port, rack number, etc.

Service options are usually visible to the customer and are defined in their contract.

Implementation attributes are internal Service Provider's properties that document the technical details of the installation.

Mandatory attributes:


    Service Unit name as displayed to the user.

  • siam.svcunit.type

    A string from a limited dictionary of predefined service unit types. It refers to a service template which identifies the attributes which are required for each unit type.

  • siam.svcunit.inventory_id

    Service Unit ID in external inventory.


A Service Unit consists of one or more physical or logical components, and each component is typically associated with physical device component. For example, a WAN connection may consist of several physical links, and each link would be identified as a Service Component.

Each Service Component object represents a single management entity, such as network port on a device.

Mandatory attributes:


    Service Component name as displayed to the user.

  • siam.svcc.type

    A string from a limited dictionary of predefined service component types. It refers to a service template which identifies the attributes which are required for each component type.

  • siam.svcc.inventory_id

    Service Component ID in external inventory.

  • siam.svcc.devc_id

    Identifier of an associated SIAM::DeviceComponent object or NIL.


Device objects describe physical or virtual devices. A device is usually a single point of management, such as IP address and SNMP access credentials.

Device objects are contained in the root object.

Mandatory attributes:

  • siam.device.inventory_id

    Reference to the device identifier in an external inventory system. This may or may not be the same as hostname.


    Device name.


  • siam.device.set_components

    The value of this condition is a JSON array of hashes, and each has represents a Device Component object and its attributes. The driver implementation should automatically delete all device components which are not defined in this array.


Device Component objects describe physical or virtual parts of a device which can be assigned to a Service Component.

Device Component objects are contained in Device objects.

Certain types of devices allow only one servcie to be associated with a device. In this case, a Device object has only one Device Component.

Mandatory attributes:

  • siam.devc.inventory_id

    Reference to an identifier in an external inventory system.

  • siam.devc.type

    Type of the component. Known values are: IFMIB.Port, Power.PDU, HOST, ...


    Name of the component, such as network port name.

  • siam.devc.full_name

    A string which represents the device component. It is supposed to be composed from the containing device's name and the component name.

  • siam.devc.description

    Component description, such as the port description configured by the network administrator.

Optional attributes:

  • siam.devc.is_attached

    If the attribute is not defined, false value is assumed. If the value is set to true, the attribute "siam.devc.attached_to" is mandatory, and it indicates that this device component is attached to another device component.

  • siam.devc.attached_to

    If "siam.devc.is_attached" returns true, this attrubute must contain the object ID of another device component within the same device. This defines the hierarchy of device components within a device (for example, a MEF EVC is attached to a physical port).


Access Scope determines the subset of contracts and other objects that are visible to particular users. The default security model provides the means for limiting access to Contracts and individual attribute names.

Two scope names are reserved, and corresponding objects always belong to them: AllContracts, AllAttributes.

Access Scope objects are contained within the root SIAM object. Each Access Scope object contains one or more Scope Member objects.

Mandatory attributes:


    Unique name of Access Scope. It has usually a mnemonic value, such as AllContracts, Contract.123456, Wholesale.654321.

  • siam.scope.applies_to

    Class of objects that this scope covers. Known values: SIAM::Contract, SIAM::Attribute.


Scope Member object points to the object at which the corresponding privileges apply.

Scope Members are contained within Access Scope objects.

Mandatory attribute:

  • siam.scmember.object_id

    ID of a corresponding Contract or Attribute object which comprises the given Scope.


User is usually associated with a physical person that accesses the system. SIAM is not responsible for authenticating the users, although it may carry the information required for authentication.

User objects may contain any of the RFC4519 (LDAP User Schema) attributes. It depends on the local interpretation which of them are available, and also the meaning of these attributes.

User objects are contained within the root SIAM object.

Mandatory attributes:

  • siam.user.uid

    Unique user ID that is known through some authentication mechanism.

Optional attributes which may be supported by the driver and the front-end application:


    Common Name attribute in an LDAP database.

  • user.auth.method

    One of two values are expected: inline, ldap

  • user.auth.password

    If method is set to "inline", this attributes delivers the password as specified in LDAP standards. Example: {SHA}NWE5MDg0MWU0ODY3Y2VjMTQ2NzU0NjNhOWEzZDFmMjI4MTFiZDQ2YnNhbHQ=


    LDAP hostname or URL

  • user.ldap.binddn

    Bind DN


Privilege is a binding object between Users and Access Scopes. The relation between users and their privileges is maintained by enterprise-specific SIAM drivers, and may be based, for example, on LDAP group membership.

Privilege objects are contained in SIAM::User objects.

Mandatory attributes:

  • siam.privilege.access_scope_id

    Reference to the corresponding SIAM::AccessScope object ID.

  • siam.privilege.type

    String from a limited dictionary of known privilege types. Examples: ViewContract, ViewAttribute, SuspendContract


Attribute objects are only used for their relation to Access Scopes. This relation is usually static and stored directly in SIAM configuration.

For example, some Implementation Attributes, such as, rack.number, would be associated with the scope ImplementarionAttributes, and only the ISP personnel users would be able to see their values.

SIAM::Attribute objects are contained within the root object.

Mandatory attributes:


    Name of the attribute.


A Report object can be contained in any of other valid objects, except for another SIAM::Report. The correspondinig container should return true value for the siam.object.has_reports attribute.

A Report object does not contain any objects. The contents of the report are retrieved via the computable.

The SIAM driver acts as a storage for report contents, and also it defines the list of reports for particular inventory objects. An external report generation program, such as Torrus SIAM plugin, generates the reports and pushes them back to the driver by setting the corresponding conditions.

Mandatory attributes:


    The report name as displayed to the user.


    A couple of sentences which describe the details of the report.


    Class of objects that are returned by this report. Usually this is "SIAM::ServiceUnit".


    A string from a limited dictionary of predefined report types. The report type defines behavior of the report generating program. Examples: "", "".


    Returns the timestamp of the latest report generation in ISO format.

Additional attributes depend on the report type, and are specific to that type. The report generation program should document all relevant attributes.

The following conditions are defined for the reports. They are used by the report generation program to store the results in the driver:


    This condition is set to tell the driver to reset the contents and add new items to the report. The value of the condition is a JSON-encoded array consisted of hashes. Each hash must have a mandatory item with the key and an object ID in the value. The rest of the keys and values is defined by the report type and should be documented in the reporting program.

The computable returns a JSON array that is comprised of the report items as specified in condition.


Copyright 2011-2013 Stanislav Sinyagin.

This program is distributed under the MIT (X11) License:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.