[Nml-wg] nmwgt -> nml

[Fausto Vetter]

Hi,

On 13-07-2012 15:11, Roman Łapacz wrote:

>> In case of pS, wouldn't be usedful to have a representation of the
>> interface as bidirectional?
> 
> It is possible to group unidirectional nml:Ports and have
> nml:BidirectionalPort
> 
> an example:
> 
> <nml:BidirectionalPort
> id="urn:ogf:network:domainx.net:2012:A:port_ge-0.2.9">
>   <nml:Port idRef="urn:ogf:network:domainx.net:2012:A:port_ge-0.2.9-out">
>   <nml:Port idRef="urn:ogf:network:domainx.net:2012:A:port_ge-0.2.9-in">
> </nml:BidirectionalPort>
> 

In case of these ps measurements I would even argue that it is useful to
have directed ports. The example is about bandwidth utilization, which
is really a measurement in one specific direction.

FV: True, but the measurement itself woudl be related to the nml:Port , but the node could be related to the BidirectionalPort (as a router/switches has physical interfaces that at the same time allows in and out traffic.


As Roman correctly pointed out, it is possible to associate both
directed Ports together, so you can programmatically find the two RRD
files and put them in the same graph.

FV: How would you do that without a BidirectionalPort? Parsing IDs? I think it would look more robust to have the BidirectionalPort representation and have the nodes composed of BidirectionalPort's.


Actually, nearly all measurements (perhaps with the exception of RTT)
are really in one direction. Think about port up/down status, bandwidth
utilization, one-way delay, ...

FV: Indeed.


>> I have seen some mentioning to this possibility in NML. I miss a
>> parameter to say the direction that the data is representing (parsing
>> IDs for that is not a clear way).
> 
> Right, in this example the direction is indicated in URN. I think
> nml:direction inside Port wouldn't be a bad idea. Freek, what do you think?

In this case, the direction is indicated by the relation between the
node and the port:

>   <nml:Node id="urn:ogf:network:netherlight.net:2010:Asd001a-ome24">
>     <nml:name>test-hostName</nml:name>
>     <nml:Relation type="http://schemas.ogf.org/nml/base/2013/10/hasInboudPort">
>       <nml:Port idRef="urn:ogf:network:netherlight.net:2010:Asd001a-ome24:1-5-4:in" />
>     </nml:Relation>
>     <nml:Relation type="http://schemas.ogf.org/nml/base/2013/10/hasOutboubdPort">
>       <nml:Port idRef="urn:ogf:network:netherlight.net:2010:Asd001a-ome24:1-5-4:out" />
>     </nml:Relation>
>   </nml:Node>

FV: Indeed, but if you start having several Port elements for each direction, how would you represent the bidirection for a single interface? ID parsing?


(PS: I see two typos here  :) ).

Regards,
Fausto Vetter

Diretoria de Pesquisa & Desenvolvimento (DPD) / Research & Development Department
Gerência de Redes para Experimentos (GRE) / Management of Network for Experiments
RNP – Rede Nacional de Ensino e Pesquisa
http://www.rnp.br
Telefone: +55 (21) 2102 9696
E-mail: fausto.vetter at rnp.br