An XML Schema for NMWG

1. An XML Schema for NMWG Yee-Ting Li, UCL

2. Metrics • All results from Network Monitoring stored in some format • Usually as a flat text file • Could store in a table in a Database • Need to convey the meaning the data and the format in which it is kept (meta data etc) • XML!

3. NMWG • Working Group at GGF • Focuses on describing metrics (characteristics) for use in Grid Environments • How to make more use of Network information • Encompasses work from IPPM • Two documents planned: • Characteristics and measurements document • Describes the structure and relationship of metrics (characteristics) against each other • Hierarchy of characteristics • Tools Document • Maps tools such as iperf and ping to specific points on the characteristic heirachy

4. NMWG Overview • Similar to IETF IPPM • But focuses more on how to use the metric rather than measure it • Defines singleton and statistical characteristics • Singletons are a specific instance of a characteristic • Statistical characteristics are formed as a result of 2 or more singletons • Defines classes of characteristics that describe WHAT you are measuring • e.g. bandwidth, delay etc. • Uses a hierachy to give structure and relationships to characteristics • Defines a ‘Measurement Methodology’ to describe HOW to measure the characteristics • Defines samples of data and their inherent sampling patterns

5. NMWG Overview • Results gathered into an Observation • Realised by a Measurement Methodology • Which measures a Characteristic • Which describes a Network Entity

6. NMWG Overview

7. An XML Schema for NMWG • XML Schemas describe the structure and content of XML document • Document language to describe virtually anything! • Uses meta data to give context to documents • Industrial standard • Cross platform • nothing more than a text file • Extensible and Flexible • Used throughout Web Services and OGSA technologies

8. NMWG Schema Goal • To be able to fully describe network metrics/characteristics • In complete and extensible way • Able to store as much information as required • Able to have as little information as required • To be used in a real system with real results • Capable to describing WHAT a tool measures and HOW and WHERE • Focusing actually implementing what the NMWG document says… and doesn’t say… • With view on actually using it to retrieve results… • As a results doesn’t always exactly match what NMWG says/suggests 

9. NMWG Schema - Overview • Measurement Methodology is root • Used to describe the application used to gather the results • The network it is conducted on • The results (observations) of the characteristics

10. NMWG Schema - measurementMethodology

11. NMWG Schema - Characteristics

12. NMWG Schema - observationSample • Tried to incorporate method of describing more than one observation at once • When we retrieve historical information of the bandwidth for the last month • May singleton values as well as statistical values • Collate all ping values for last year! • Some tools may report more than one characteristic • Eg ping: 2WD and loss, traceroute: rtt and path, pipechar: capacity and path etc.

13. NMWG Schema - observationSample

14. NMWG Schema - Example • Ping • <XML Spy/>

15. NMWG Schema - Example • Iperf • <XML Spy/>

16. NMWG Schema - Example • Traceroute • <XML Spy/>

17. NMWG Schema - Example • pipechar • <XML Spy/>

18. Summary • A useable implementation of XML Schema for Network Monitoring • Can report single observations or a group of observations in a single document • Demonstrated suitability for most common monitoring tools • Easily extended to most tools • Also includes non-network information that may contribute to poor network performance • Host configuration, kernel parameters etc. • However doesn’t quite fit into NMWG framework • Needs further refinement of both the Schema and what NMWG define