Data Modeling IETF68 - Prague Dr. Michael Alexander Department of Information Systems Wirtschaftsuniversität Wien malexand@wu-wien.ac.at

Agenda Use Cases Problem Statement Backward Compatibility Scope Core Secondary Non-in-scope Functional Coverage

Agenda II Requirements on Others Approach Process Integration Open Items References

Use Cases Designing and Implementing Functional Coverage Element Managers (EMSs) Network Managers (NMSs) Operations Support Systems (OSSs) CLIs Functional Coverage Configuration Alarms Current-historical performance Inventory Accounting management Security

Problem Statement Every device, EMS, NMS, Alarm manager, inventory manager tends to have its ITS OWN DATA MODEL Popular access method focus “we manage with SNMP, CLI, CORBA etc, “ … NM sometimes secondary outside of carrier because of high cost of proper enterprise NM Flatness of SMI/MIBs Try building a multi-device EMS/NMS from it … Behavior weekly expressed in MIBs Time it takes to model a new device, add additional release support is excessive

Problem Statement II "Although some positive sentiment was expressed for defining a kind of "super SMI" metalanguage to aid in the definition of a general API, it was not clear whether the current crop of supporting protocols had sufficient semantic commonality to be used in this way. The matter remains open for investigation." Vince Cerf RFC 1109 (1989)

Backward Compatibility Axiom: Backward compatibility with MIBs SHALL be preserved Building on MIB base Man hours in existing MIBs ... Conversion of MIBSs to DM Models Into namespace, free form variant Reverse imports of DM Models into MIBs not feasible

Independence from Access Method Data Models need to be independent of access methods „Talking to a device via SNMP || CLI || NETCONF || CORBA || XML-RPC || Batch Config Transfer“ is relatively insignificant in time/resources relative to designing-implementing-maintaining data models ... A clean data model of a 5000 managed objects device can be talked to in ANY of the above access methods provides the device has an agent that exposes the objects

Scope: Core I Initial focus: Must: Equipment hierarchy Rack/ Power supplies/ shelf/ slot/ port/ facility/ protocols…/ services Must: Base network types: IP, SDH/SONET, ATM, Ethernet Proposed initial focus: IP-Routing, Ethernet, SDH/SONET, ATM Proposed initial services: Barebones SIP, Ethernet VLANs, DiffServ (as a service in the models)

Scope: Core II Layer Description Layer VII Device/Line/Service/Protocol Instance Layer VI Device/Line/Service/Protocol Model Layer V Device/Line/Service/Protocol Type Meta Model derived from class model Captures behavior, rules Layer IV Device/LineService/Protocol Class Meta Model Alarm template class model Layer III Namespaces/Meta model (realize definition files, build NM) Derive from existing CLI (option?) or design anew Constructs etc. Alarm template meta model Layer II Object Model (prototype methods-operations, data types) Layer I Access Method (snmp, cli, netconf, cmip, corba, xml-rpc, soap ...)

Scope: Secondary Unique equipment/line locator Schema for it Registry - tirks providers (function code) Alarm template registries Protection, failover modeling (1+1, 1:n, 1:1, etc.) Device/service/protocol models to be defined in the respective areas / WGs Needs namespace/metamodel Otherwise chaos results …

NOT in Scope Business Support Systems (BSS) Workflow Trying to solve the remaining 20%“ to 100% of networks/services from the onset ...

Requirements on Others-Dependencies No initial requirements but of: Netconf RPC/method call Coarse grained operations on the device’s protocol agent significantly reduce level of complexity: provision_subscriber () vs. 100 Sets … Consecutively elegant integration into protocol specifications natural Management gets much easier for protocol designers if Protocol Class Meta Model is derived from

Approach Talking Points "80% easier to understand, 90% less time", VERY SIMPLE upper layer models … Applies if you have thousands/ten thousands of NEs and small … Not a monolithic model ... No device class/service xsds etc. without meta models … Leave 100% to all-inclusive models … Process is crucial ... .net example ... Fostering exposure of methods in NEs … One draft rules them all does not work here … Many folks not used to meta modeling … Overspecify ... Good expressiveness necessary ... Good but not perfect coverage, completeness, correctness … Iterate … Not going to solve the world … but 80% of it ;) Human readable schemata and models a key criterion Models will do some things like IP very well … Use of 2-3 sample stacks: e.g. ATM stack or Site-to-Site IPSec Tunnels/POS/MPLS/SONET-SDH … Sensible abstraction, decomposition where necessary … integration-produce something that fits together … importance of meta models/frameworks ...

Process-Cycle Time Complexity is significantly higher than for many protocols (not TCP) Just as much an organization and process exercise Expected high intial flow of changes until steady-state, still comperatively many changes as part of regular process in regular update cycle Device/Line/Service/Protocol Models should be shifted to respective areas Branches Folding of normative schema extensions into main as much as possible Allow private branches Allow specialization without folding Target time: 1 year for first iteration Cycle time: Device/Line/Service/Protocol Instances: on discretion of equipment/nm vendors Device/Line/Service/Protocol Model: initial: 6 months, steady-state 6 months Synced with protocols All meta models: initial: 6 months, steady-state 8-9 months Object model and data types: initial: 6 months, steady-state 3-4 years or longer

Open Items Rules language State model inclusion and language (1) and (2) .. equivalent to not having reached the moon and wanting to go to another galaxy ...

Towards a BOF Terminology Is the problem worth working on In NM time gets wasted when differing terminologies are used ... Is the problem worth working on Is the problem defined well enough For a BOF … Creating layer V models first is futile need to be converged … Jumpstarting the effort: e.g. basing it on IOS/JUNOS CLI (evaluate legal, practical possibility) MIB to XML conversion to be formalized NOW <draft-chisholm-netconf-model-06.txt > is close to a Layer II object model Should a BOF be held at IETF69

References RFC 1155 - SMI RFC 1157 - SNMP RFC 1212 - Concise MIB Definitions RFC 3688 - XML Schema RFC 4741 - Netconf W3C Namespaces in XML, 1999 W3C XML 1.0 4th Edition, 2006 <draft-alexan-datamod-00.txt> <draft-atarashi-ngo-consider-architecture-00.txt> <draft-chisholm-netconf-model-06.txt> <draft-okita-ngo-diffservdatamodel-00.txt> <draft-iijima-ngo-vlandatamodel-00.txt> <draft-romascanu-netconf-datatypes-01.txt>