Protocols and Messages
The NMWG schema The Global Grid Forum’s Network Measurement Working Group (NMWG) XML schema is used to represent measurement data. It segments the measurement data presentation in two parts: the metadata and the data.
Figure 2‑1 - NMWG format / data and metadata
Metadata describes the type of measurement data, the entity or entities being measured, and the particular parameters of the measurement. The data itself is simply a timestamp and a vector, or array, of values.
Figure 2‑2 - NMWG format / data and metadata
The actual version of the NMWG schema used is version 2. It is available on the GGF NMWG web page.
perfSONAR messages
perfSONAR services exchange NMWG messages. The NMWG schema is not only used to describe measurement data, but also to exchange those data between services. These messages are carried in a SOAP message, carried over HTTP. The whole chain of protocols used to exchange messages is presented in the figure below:
Figure 2‑3 - perfSONAR message
More details about the schema description and perfSONAR messages in general can be found on the perfSONAR wiki.
