perfsonar development work

[Nicolas Simar <>]

Matthias K. Hamm wrote:
> Hi Nicolas,
>
> please find our comments inline.
>
> Nicolas Simar schrieb:
>
> > Hi Maciej, Mark and Matthias,
> >
> > Maciej Glowiak wrote:
> >
> > > Hi Nicolas,
> > >
> > > Nicolas Simar napisał(a):
> >
> >
> > > > > I can help and write particular XQuery expression for you if you 
> > > > > give me XML example of Lookup Information.
> > > >
> > > >
> > > >
> > > > You mean that we should provide the information that will be 
> > > > registered in the LS.
> > >
> > >
> > >
> > > Yes.
> >
> >
> > During yesterday conf call with JRA3-4, it was mentioned that at this 
> > stage, the discovery functionality isn't needed as the visualisation 
> > tools download all the L2 circuit information from the MA/MPs and 
> > stitch them together to display them. So it seems that at this stage, 
> > the functionality isn't needed yet for JRA3-4 application.
> >
> > It was mentioned that at some point, some scalability issues may be 
> > encountered and that a discovery mechanism may be needed. However, no 
> > information explaining when the scalability issues would be 
> > encountered were given.
> >
> > Can I ask Mark and Matthias to give an estimate about when their tool 
> > would need to use a discovery mechanism (because too many MA/MP, 
> > because new circuits are coming regularly and the number of MP/MAs 
> > varies greatly, or because too many circuits and a manual file doesn't 
> > do it anymore).
>
> We don`t expect scalability issues. Following our architecture, we do 
> not need a discovery mechanism for L2 circuit information. Howerver, we 
> would like to have the possibility of finding the URLs to MPs and MAs by 
> using a lookup service. This should also solve the poblem of discovering 
> backup for unreachable MPs/MAs.

The querry you would expect to run would be the following:
"Give me the list of services where I can find L2 status information." 
and you would be returned a list of MAs and MPs (and domains or just the 
URL?), plus a list of LS to contact to get furhter information (as the 
LS are distributed). The you can ask recursively the question to the 
other LSes (filtering out the ones you have already visited).

Jason, is it how it will be expected to work?

> > However, as part of the perfSONAR, we need to cater for other 
> > visualisation or analysis tool (e.g. build by some NOC for punctual 
> > troubleshooting). They may have the requirement to discover:
> > (1) all the e2e circuits from a project, then all the MPs/MAs 
> > containing the relevant information in respect with those e2e circuits
> > (2) find out a particular e2e circuits based on the end-institution 
> > (and maybe the project name)
> > (3) find out all the information related to an end-to-end circuit (so 
> > the MAs/MPs where the information is located).
> >
> > For 3, you need to know the e2e circuit name and you expect to get 
> > back, by querying the LS, the list of <domain-link, MA/M Paddress> / 
> > <inter-domain-link, MA/MP address > that are associated with the e2e 
> > circuit id. (or the <MA/MP address, list of link id>
> > From there, you can querry the different MA/MP and recompose the e2e 
> > path, except that at this stage, the MP can will only return you the 
> > list of all circuits when being queried.
> >
> > (2) seems to require more information than just the e2e circuit id, 
> > the domain/inter-domain link id and the MA, MP where this info needs 
> > to be located. So I would set it aside for the time being.
> >
> > (1) need one piece of information in addition to the triplet mentioned 
> > above: the name of the project having requested that circuit. Do we 
> > wish to add this in the information we plan to register to the LS? 
> > (who would register it, all the domain? What happens if people write 
> > the project name differently?)
> >
> > Matthias and Mark, is it correct that the minimum information that a 
> > MP/MA would need to register to a LS would need to be <e2e circuit id, 
> > domain-link, MA/MP address> / <e2e circuit-id, inter-domain-link, 
> > MA/MP address> and that should be sufficient to be able to retrieve 
> > the info of a L2 circuit.
>
> The information you have mentioned will be partly stored in cNIS. It is 
> always a good idea to avoid having data redundancy between different 
> services ;-)

that raises the point about the co-existence of the cNIS and the lookup 
service to some extend.

> Although some kind of E2E link name registry is necessary (something 
> more enhanced than collecting names on HTML pages), it is a major 
> question if the lookup service is the right place to store this 
> information. Escpecially, if the LS is a distributed service ;-)

What type of request would you like to do and what would you like to get 
as answers?

Nicolas

> > Cheers,
>
> Cheers,
>
> M&M

--
Nicolas
______________________________________________________________________

Nicolas Simar
Network Engineer

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