[Nml-wg] DCN glossary

[Ralph Niederberger]

Dear John and all,

only some information which could influence some definitions.

I had some discussion with GARR (Italian NREN) concerning Endpoint and 
Demarcation point
of an E2E path. Background is the following:

GEANT2 provides wavelength throught their infrastructure which can be 
prolonged on both sides by
wavelengths of NRENs. DEISA has rent such a kind of 10 Gbit/s End to End 
Service (e2e).

E.g.
DEISA site FZJ Juelich, Germany <-> fiber cable
       < -> DWDM equipment at PoP of local NREN DFN in Juelich, Germany 
<-> fibre cable with DWDM
               <-> DWDM equipment of local NREN DFN at GEANT2 PoP in 
Frankfurt, Germany <-> fibre cable
                      <-> DWDM equipment of GEANT2 at Frankfurt, Germany 
<-> fibre cable with DWDM
                             <-> DWDM equipment of GEANT2 at London, UK 
<-> fibre cable
                                    <-> DWDM equipment of remote NREN 
JANET <-> fibre cable with DWDM
                                            <-> DWDM equipment at PoP of 
remote NREN JANET at Daresbury, UK <-> fibre cable
                                                   <-> DEISA remote site 
EPCC Daresbury, UK

For monitoring purposes the "GEANT2 End2End Coordination Unit" (E2ECU) 
has setup a
domain related monitoring tool.
Each domain provides its information of the path (e.g. Path is 
administratively or operationaly up or not).
Measurement points between domains are demarcation points.
Both ends of the link between two domains provide partial information. 
So concerning to this definition

GARR argues that the end of the provider links are the end point of the 
path, i.e. the outgoing interfaces of
the DWDM equipment.

IMHO the ends of the path are the incoming interfaces of the two sides 
which have requested the e2e path.

So your definition would give room for some interpretation:
"path - a connection between a source and destination.  A path is a 
sequence of hops."
 
We all know, that we assume as path (at least within IP) the connection 
from source (outgoing interface)
to destination (incoming interface). But others (e.g. Service providers) 
could argue in a different way. 

best regards

Ralph
John Vollbrecht schrieb:
> Attached is a DCN glossary which is part of DCN architecture and DCN 
> reservation documents.
>
> Of particular note are some terms we  use that don't seem to be in the 
> NML schema (perhaps I am wrong?)
>
> path - a connection between a source and destination.  A path is a 
> sequence of hops.
> source - starting point of path - as defined by direction of signalling
> destination - end point of path- as defined by direction of signalling
> hop - a network element - [domain or node or port or link]
>
> path segment - subset of a path consisting of two or more hops
> circuit - a connection between tow endpoints that can be used to 
> transmit data between them
>
> I note that in the glossary some information is assumed, in at least 
> some of the definitions.  In particular, a path (perhaps a DCN path) 
> must include time/duration and resource.  That is, a Link may carry 
> multiple paths at a given time, and may carry different paths 
> sequentially.
>
> I am wondering if this or something like it can be incorporated (or is 
> incorporated) in NML.
>
> John
>
>
>
>
> John Vollbrecht, Senior Network Engineer
> Internet2
> office +1-734-352-4960 | mobile +1-734-395-7890
>
> ------------------------------------------------------------------------
>
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> nml-wg mailing list
> nml-wg at ogf.org
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>   

-- 

***************************************************
 Ralph Niederberger
 Juelich Supercomputing Centre
 Institute for Advanced Simulation

 Phone:  +49 2461 61-4772
 Fax:    +49 2461 61-6656
 E-Mail: r.niederberger at fz-juelich.de
 WWW:    http://www.fz-juelich.de/jsc/

 JSC is the coordinator of the
 John von Neumann Institute for Computing
 and member of the
 Gauss Centre for Supercomputing
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