[Nml-wg] modelisation of the network description and dynamic circuits

[Aaron Brown]

Freek Dijkstra wrote:
> I strongly disagree with this ad-hoc solution:
>
>   
>>           <link id="I2_host2_eth1_link" />
>>           <vlanAvailability>400-800</vlanAvailability>
>>     
>
> Because:
> * the semantic is very technology specific. I rather see a more general 
> model (in this case such as the label concept in GMPLS or multiplexing 
> adaptation in G.805).
> * the syntax is very ad-hoc. The power of XML is that you can compose 
> properties of object in detail. Why use regexp syntax like "400-800" 
> instead of <range><min>400</min><max>800</max></range>
>   
The focus of my example was more on clarity (single port vs. multiple 
port) than a specific set of requirements. In the more general model, 
there'd be a property that elements could have describing the possible 
sub-element that can be constructed. In this case, it would be the set 
of vlans. So, it might look like this:

<sub-elements-options type="vlans">
    <range>...</range>
    <range>...</range>
    <range>...</range>
</sub-element-options>

Sonet channels could look similar:

<sub-elements-options type="sonetChannels">
    <range>...</range>
    <range>...</range>
    <range>...</range>
</sub-element-options>

The sub-element-options might even be a better way of describing the 
possible choices for a virtual port since the specific one has not yet 
been selected:

<network id="I2">
    <!-- define a logical interface between NY and Paris -->
    <port id="I2_NY_to_GEANT-Paris">
        <sub-element-options type="elementChoice">
            <!-- include references to the actual physical ports -->
            <port id="I2_host1_eth0" />
            <port id="I2_host2_eth1" />
        </sub-element-options>
    </port>

    <!-- define the physical interface/link from host1 in NY to Paris -->
    <node id="I2_host1">
        <port id="I2_host1_eth0">
           <link id="I2_host1_eth0_link" />
        </port>
    </node>

    <!-- define the physical interface/link from host2 in NY to Paris -->
    <node id="I2_host2">
        <port id="I2_host2_eth1">
           <link id="I2_host2_eth1_link" />
        </port>
    </node>

</network>

Is this in line with what you were thinking?

Cheers,
Aaron

>
>   
>> My question is how one describes a link as a set of VLANS
>>     
>
> John, I'll write how we describe adaptations later. That first requires
> a discussion on what a "layer" is (an OSI layer, technology, or sublayer
> withing a technology). For now, please see e.g. the mail Jeroen sent to
> the list recently about how adaptations are done in ITU-T G.805.
>
>   
>> Case 2 - Between I2-NY and GEANT-Paris we want to create multiple GE 
>> circuits which can be used to create connections between I2 and GEANT.  
>> One way to do this seems to be to create a "traffic engineering-link" 
>>     
>
> According to G.805, a link connection (= TE link above) can be made on a
> server layer by terminating a network connection on a client layer.
>
> Either we simply want to describe that TE link, or we want to describe
> the terminated and adaptated network connection that creates the TE
> link. Possibly we want a model were we can do both. How exactly this is
> described is open. I guess we first need to discuss what a "path" is
> (I'd say G.805 tandem connection) and what a link is (I'd say G.805 link
> connection), and also what a layer is.
>
> We haven't discussed these concepts so far. So feel free to step in and
> make suggestions about classes and relations.
>
> Regards,
> Freek
>
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