perfsonar development work

[Giovanni Cesaroni <>]

Hi,
some answers inline

On 09/06/2010 03:33 PM, Freek Dijkstra wrote:
> Hi all,
>
> In Geant3, we want to add cross-layer functionality to E2Emon. We're
> currently considering a few options, and have a few questions we like to
> get straightened up before we propose those options.
>
> For ease of discussion, here is an example topology information as
> served by our current E2Emon service.
> (see also e.g.
> http://cnmdev.lrz-muenchen.de/e2e/lhc/mon/G2_E2E_view_e2elink_CERN-TRIUMF-LHCOPN-001.html)
>
>   <?xml version="1.0" encoding="UTF-8"?>
>   <nmwg:message
>     xmlns:nmtl2="http://ggf.org/ns/nmwg/topology/l2/3.0/";
>     xmlns:nmwgtopo3="http://ggf.org/ns/nmwg/topology/base/3.0/";>
>   [...]
>     <nmwg:metadata id="metadata.11891256">
>       <nmwg:subject id="sub.8014380">
>         <nmtl2:link>
>           <nmtl2:name type="logical">
>             5004LE-asd001a_ome13-1-13-2</nmtl2:name>
>           <nmtl2:globalName type="logical">
>             CERN-TRIUMF-LHCOPN-001</nmtl2:globalName>
>           <nmtl2:type>ID_LinkPartialInfo</nmtl2:type>
>           <nmwgtopo3:node nodeIdRef="NETHERLIGHT-AMS">
>             <nmwgtopo3:role>demarcpoint</nmwgtopo3:role>
>           </nmwgtopo3:node>
>           <nmwgtopo3:node nodeIdRef="CANARIE-CHCG1OME2">
>             <nmwgtopo3:role>demarcpoint</nmwgtopo3:role>
>           </nmwgtopo3:node>
>         </nmtl2:link>
>       </nmwg:subject>
>     </nmwg:metadata>
>   [...]
>   </nmwg:message>
>
> Basically, this describes a port with attached link,
> "5004LE-asd001a_ome13-1-13-2", which is part of the end-to-end circuit
> "CERN-TRIUMF-LHCOPN-001". Furthermore, this link is between nodes
> NETHERLIGHT-AMS and CANARIE-CHCG1OME2.
>
> We have a few observations (or assumptions if you will). Can you confirm
> if those are correct?
>
> - The name "5004LE-asd001a_ome13-1-13-2" refers to the bidirectional
> link between NETHERLIGHT-AMS and CANARIE-CHCG1OME2, even though the
> peering domain would use another link description (in this case, CANARIE
> describes it as "CANARIE-TRIUMF-CERN_ChiNYC").
>    
correct
> - The links are matched based on the nodes (nodeIdRefs) and end-to-end
> path name (globalName).
>    
correct
> - The node names are supposed to refer to device names, not to domain
> names. Thus if the (name of a) node at a domain boundary chances, all
> peering domains must chance their description as well.
>    
correct
(in few cases the node name is the name of a PoP and not of a device, 
but it doesn't change the meaning of your  assumptions)
> - However, if the link name chance (e.g. because the interface chances)
> at a domain boundary, the peering domains need NOT to chance their
> descriptions.
>    
correct
> - It is possible to describe multiple channels over a single physical
> interface by describing each channel with a different logical name. For
> example, assume that the above link between NETHERLIGHT-AMS and
> CANARIE-CHCG1OME2 carries 2 channels, the link logical names could be
> 5004LE-asd001a_ome13-1-13-2-channel-1 and
> 5004LE-asd001a_ome13-1-13-2-channel-2. In this case, the peering domain
> must also describe each channel with the same end-to-end path name
> (globalName) and node names.
>    
mmm, I'd understand better the observation if you make some examples.
What do you mean with channel?
(If you mean for example a vlan, you could describe the vlan as an e2e...)
Same for the next

> - The matching assumes that all LinkPartialInfo descriptions with one
> common nodeIdRef are connected (have a cross-connect) at that node. Thus
> a theoretical scenario where one would have two separate cross connects
> for the same end-to-end path in the same device can not be described in
> E2Emon (for a single layer this indeed makes no sense, for multiple
> layers, such "loops" may indeed exists, even though they are not still
> rare).
>
> Regards,
> Freek Dijkstra and Peter Tavenier
> SARA
>    
Cheers,
Giovanni

--
Giovanni Cesaroni
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CONSORTIUM GARR
The Italian Academic and Research Network

Tel. +39 06 4962 2535
Fax  +39 06 4962 2044
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