NetConf Data Model draft-adwankar-netconf-datamodel-01.txt Sandeep Adwankar

Why Data Model? Interoperability Non-trivial implementation – ifTable (UnDefined) – Nothing Defined –

Do we need information model? Are relations important to be modeled –Is it just “ref” in XML schema, if so it is containment Is aggregation important to be modeled –Yes, but isn’t it inherent to XML Is abstraction layer important –Yes, and XML schema provides it Is representing complex interrelationship important –Xpath allows retrieving complex content from bunch of simple elements

Do we need information model Are graphical design methods (e.g. UML) important –Number of tools available for XML Schema that generates diagrammatic representation Is having single common model important –XML allows transformation using technologies such as XSLT Do we need one more information model –Allow translation mechanisms –E.g. CIM Provider in case of CIM –E.g. NGOSS information steward in case of SID

Survey of Data Models Structure of Management Information Structure of Policy Provisioning Information Common Information Model Device Description Framework Web Services Distributed Management

Why XML Schema Support range of predefined types allowing strong type well as constraints checks Allows use of regular expressions Allows reusable types and creation of new types with inheritance Rich in constructs such as for grouping and for defining abstract layer Tools available for graphical representation and code generation Provides tools for translation of content (XSLT) and locating content (XPATH)

Data Model Design Objectives Simple and Lightweight Provide interoperability amongst NetConf entities Allows derivation of the NetConf Data Model to develop model for each device –OO feature to inherit the data model and to minimize impact of changes in the data model Evolutionary model that uses wealth of existing information –E.g. MibDepot offers access to 6200 SNMP MIBS Provides standardized migration path for those MIBs instead of proprietary CLIs

Data Model Design Objectives Minimize dependence on NetConf Protocol –Should be beyond just configuration Minimal definition of data model –Not to define explicit containers, if a container hierarchy can be obtained through XPATH Alignment of various data models at the level of exchange –Technologies such as XSLT can be used without creating a common schema/model Aid in creating non-trivial implementations

Data Model Design Every Managed Object inherits from a Generic Node Each managed object value is simple type and can be type-checked or constraints checked –For container value indicates type of container such as either sub-tree, table, entry

Data Model Design Each Managed Object definition must provide –Parent –Max Access –Status –Description Managed object value is designed as an attribute to minimize hierarchy and since it is simple type A container managed object definition includes references to other managed objects

Data Model Schema

sysDescr Definition <element name="description" type="nc:Description" fixed="A textual description of the entity. This value should include the full name and version identification of the system's hardware type, software operating-system, and networking software." minOccurs="0"/>

Naming Must support relative URI based addressing –./system/sysName Should support Xpath

Naming++ Locate managed objects Select set of managed objects based on a set of criteria’s Create container structure based on different managed object values Create simple expressions such as + div ) Corresponds to (ifInOctets + ifOutOctets) * 800 / ifSpeed

ACL List of ACL entries that may include ACL of parent ACL Entry –access list, a list of NetConf protocol operations –identifier list that groups accessors together –Access duration, duration over which an ACL entry is valid

ACL

ACL Example... *

Compliance Grouping construct to group related managed objects together Schema compliance element provides compliance statement

Key Constraint Define “key” constraints to ensure –Managed object must be present –Managed object value must be unique