The NMWG Framework A (very) brief introduction Raphael Dourado 13/04/20121

Introduction There are a lot tools for network measurement but it’s necessary a standardized way for representing all of these information Thus, the NMWG schema goal is to define “an extensible system for storing and processing performance information in distributed environments” 13/04/20122

Basic Principles There is a clear separation of “time-varying, monitoring data” from “infrequently changing metadata” – It helps in making the system scalable – Differs from earlier approaches because the separation here is explicit – Also helps in normalizing the measurement layout The separation between Data and Metadata 13/04/20123

Basic Principles Although it’s not a “brand new” idea, there are two updates – The use of WebService-friendly IDS (URI instead of OID) – The schemas are arranged in a way so that the “required” elements are minimized These improvements allows “new measurements to easily and independently extend the basic framework” The use of XML as the data exchange format 13/04/20124

A Simple Example Data/Metadata in a traceroute measurement Data Metadata 13/04/20125

A Simple Example Metadata – Tool used (Windows’ “tracert”) – Source host (Raphael’s PC) – Destination host (cin.ufpe.br) – Parameters (-h 15) Data – IP address and elapsed time of each network probe Data/Metadata in a traceroute measurement 13/04/20126

The NM-WG Base Schema Message MetadataData Subject EventType Parameters CommonTime Datum 13/04/20127

The NM-WG Base Schema Subject – The physical or logical entity being described Ex.: – “ICMP latency from A to B” Metadata Section Message MetadataData Subject EventType Parameters CommonTime Datum Subject 13/04/20128

The NM-WG Base Schema EventType – The name of the aspect being measured (the characteristic) Ex.: – “ICMP latency from A to B” Metadata Section Message MetadataData Subject EventType Parameters CommonTime Datum EventType 13/04/20129

The NM-WG Base Schema Parameters – The way in which the data is being gathered Ex.: – “ICMP latency from A to B, when using 100 byte packets” Metadata Section Message MetadataData Subject EventType Parameters CommonTime Datum Parameters 13/04/201210

The NM-WG Base Schema CommonTime – A flexible way to represent time Datum – The actual measurement data Data Section Message MetadataData Subject EventType Parameters CommonTime Datum 13/04/201211

The NM-WG Base Schema Piecing together When you use 100 byte packets, Host A to Host B ICMP latency is 100ms. Metadata - Parameters Metadata - Subject MetaData - EventTypeData 13/04/201212

Example Messages (OWAMP Request) Metadata 13/04/201213

Example Messages (OWAMP Response) /04/201214

Examples of Schema Definition 1513/04/2012 NMWG schemas are usually defined using the RELAX-NG language This is an example of OWD definition in RELAX-NG – ema/rnc/owd.rnc ema/rnc/owd.rnc Here are more examples – ema/rnc/ ema/rnc/

Extending the Base Schema Yes! More information can be found at – “NMWG Schema Developers Guide”, section 5 And also at /devguide/devguide.pdf, section 6 (newer version, but worse explanation) /devguide/devguide.pdf It is possible? 13/04/201216

References Zurawski, Jason et. al. A Scalable Framework for Representation and Exchange of Network Measurements. TridentCom, /04/2012

THANK YOU! QUESTIONS? 13/04/201218

Backup Slides 13/04/201219

Since NMWG uses XML for data representation, it is necessary a XML schema language – The chosen language was RELAX-NG 13/04/201220