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

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

3. Agenda II Requirements on Others Approach Process Integration Open Items References

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

5. Use Cases II (C) servasoft Drilling-down into equipment

6. 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 weakly expressed in MIBs Time it takes to model a new device, add additional release support is excessive

7. 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)

8. 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

9. Independence from Access Methods 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

10. 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)

11. Scope: Core II LayerDescription Layer VIIDevice/Line/Service/Protocol Instance Layer VIDevice/Line/Service/Protocol Model Layer VDevice/Line/Service/Protocol Type Meta Model derived from class model Captures behavior, rules Layer IVDevice/Line/Service/Protocol Class Meta Model Alarm template class model Layer IIINamespaces/Meta model Derive from existing CLI (option?) or design anew Constructs etc. Alarm template meta model Layer IIObject Model (prototype methods-operations, data types) Layer IAccess Method (SNMP, CLI, Netcon, CMIP, CORBA, XML-RPC, SOAP...)

12. Scope: Secondary Unique equipment/line locator – Schema for it – Registry 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 …

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

14. Requirements on Others- Dependencies No initial requirements but of: – Netconf RPC/formalized method call (work-around available) – 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 available.

15. 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...

16. 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

17. Open Items 1.Rules language, metamodel language 2.State model inclusion and language

18. Towards a BOF 1.Terminology – In NM time gets wasted when differing terminologies are used... 2.Is the problem worth working on 3.Is the problem defined well enough – For a BOF … 4.Creating layer V models first is futile – need to be converged … 5.Jumpstarting the effort: – e.g. basing it on IOS/JUNOS CLI (evaluate legal, practical possibility) – MIB to XML conversion to be formalized NOW – is close to a Layer II object model 6.Should a BOF be held at IETF69

19. 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