perfsonar development work

[Jason Zurawski <>]

Ulisses;

> Hi all
>
> using the following xml sample as a base [0]:
>
>  

<snip>

> I see that the select element has a reference to metadata that describes an 
> xml document.
>
> In the topology service, it will be interesting for future versions to 
> retrieve only a a set of
> elements of the topology, for instance the links that have an specified 
> capacity.
>
> An example of link element is the follwing:
>
>         <nmwgtopo3:link  id="localhost.localdomain.-4b42ecf6:10d5e1bdbe3:-6b38" 
> xmlns:nmwgtopo3="http://ggf.org/ns/nmwg/topology/l3/3.0/";>
>             <nmwgtopo3:interface
>                 id="localhost.localdomain.-4b42ecf6:10d5e1bdbe3:-6b39" 
> interfaceIdRef="51479">
>                 <nmwgtopo3:ifDescription>FastEthernet0/0.2-ISL vLAN 
> subif</nmwgtopo3:ifDescription>
>                 <nmwgtopo3:type>other</nmwgtopo3:type>
>                 <nmwgtopo3:capacity>100000000</nmwgtopo3:capacity>
>                 <nmwgtopo3:ipAddress value="158.38.108.1"/>
>             </nmwgtopo3:interface>
>             <nmwgtopo3:type>lan</nmwgtopo3:type>
>             <nmwgtopo3:name>levanger.levanger-fag</nmwgtopo3:name>
>         </nmwgtopo3:link>
>
>
> And a template of links that have interfaces with a capacity of 155 Mbps 
> could be [1]:
>
>      <nmwgtopo3:link>
>            <nmwgtopo3:interface>
>                       <nmwgtopo3:capacity>155000000</nmwgtopo3:capacity>
>            </nmwgtopo3:interface>
>     </nmwgtopo3:link>
>
> I don't have clear that I can specify such template inside a <select> 
> parameters so I believe
> that the correct way to indicate the template is like in the example [0], that is referencing a 
> metadata that has the template element [1]
>
> A full example could be:
>
>   <nmwg:metadata id="meta1">
>     <netutil:subject id="sub1">
>      <nmwgtopo3:link>
>            <nmwgtopo3:interface>
>                       <nmwgtopo3:capacity>155000000</nmwgtopo3:capacity>
>            </nmwgtopo3:interface>
>     </nmwgtopo3:link>
>     </netutil:subject>
>   </nmwg:metadata>
>   

The namespace of subject is wrong here (it should be just nmwg, or 
something else generic), but the idea is correct. 

>   <nmwg:metadata id="meta2">
>     <select:subject id="sub2" metadataIdRef="meta1"/>
>
>     <select:parameters id="param1">
>       <nmwg:parameter name="Time">0</nmwg:parameter>
>     </select:parameters>
>
>     <nmwg:eventType>select</nmwg:eventType>
>
>   </nmwg:metadata>
>
>
>   

I am not sure what you mean by:

<nmwg:parameter name="Time">0</nmwg:parameter>

in this example.  You are trying to get all link elements, with that 
capacity, that start after time 0?

Your example is more or less correct, and we did intend for the 
parameters to be used in this fashion when interacting with databases 
and other backend storage.  It will be necessary (as you are designing 
your service) to define what possible 'fields' can be selected upon (for 
example the rrd ma can specify a startTime, endTime, 
consolidationFunction, or resolution; these have some sort of meaning to 
the backend and need to be well described in the instance documents). 


-jason