Re: [GLIF controlplane] RE: Network Control Architecture

[Bram Peeters <bram.peeters@xxxxxxxxxx>]

Hi Gigi, Inder, all -

Interesting discussion -

On (B) - I do indeed remember a pretty healthy discussion on that in 
Minneapolis, both on the single RB accessing other domains, and some 
more discussion on policy/authentication. I think what Gigi states in 
her response is actually pretty much what we ended up with - the idea 
that an "interdomain broker" would access all local NRBs / NRMs / NARBs 
/... This would solve the problem of having distributed commit issues, 
and basically quite a lot of other distributed issues such as routing, 
policy control,...

In Phosphorus WP1 a similar approach has been taken with the 
introduction of the NSP (network service plane) that will talk to all 
domains involved through a "standard" interface (or basically all domain 
NRMs support the same set of request/response messages to allow the NSP 
to create an end-to-end connection). Doing it this way and not a complex 
distributed system was initially required to get a reasonable chance of 
actually getting something working by the target date of end October 
2007 - which is still some time away. However - I start to like that 
approach more and more, as it seems quite a few problems become less 
problematic, and I can see ways of doing policy / resource control and 
authentication in such a system.

That approach where for an application's request a single entity 
contacts all domains is - if I look carefully - at the top-level the 
same as the network-bit on the slides that Gigi sent, where the RB would 
be the Phosphorus-NSP-like application, and the NRM is 
DRAC/UCLP/Viola/anything else. For Phosphorus WP1 only the GNI arrows 
are relevant, and due to only one NSP being developed the resource 
registry where (topology + interconnect) resource info from the 
different domains is published is contained inside the NSP as well.

On a side note - I'm not convinced (yet??) that a single resource broker 
will do the multi-domain, multi-technology brokering - I'd be looking 
for a metascheduler/broker that talks to one RB/NSP that will hide all 
the gory details of networking issues to the Grid app (routing, 
networking technology stitching,...), so one more layer of complexity 
before you get from the network to the application. And it would limit 
the number of acronyms I need to remember for now ;-)


Bram







Gigi Karmous-Edwards wrote:
> Hi Inder,
>
> Thank you for your comments.
>
> A)  We use Grid in terms of the concept of "resource sharing".  In 
> terms of the the interfaces that we all will develop together there 
> will be no Grid relevance. The framework only shows functions and 
> tries to specify interfaces to be standardized. Implementations of the 
> resource broker (RB) and resource mangers (xRM) could be completely 
> independent of Grid technology. We are assuming that a network 
> resource manager could be implemented in various ways which may or may 
> not include Grid components. An example of an Domain Network Resource 
> Manager (DNRM) could be based on DRAC, UCPL, or GMPLS, etc
>
> Another reference to Grid came from the name of the GLIF group, "GLIF 
> Control Plane and Grid Middleware" working group.  In my personal 
> opinion, we can just call it middleware rather than Grid middleware. 
> To conclude, the interfaces will not have Grid specific attributes but 
> will accommodate Grid applications.
>
> B) I understand your concerns. This topic was discussed at great 
> length, and I do not think we are all on the same page on this topic. 
> The motivation for allowing a resource broker (RB) access to another 
> domain's resource manager (xRM) is due to the transaction problem 
> associated with the coordination of multiple resources. The 
> implementation of the phase commit is currently the responsibility of 
> the resource broker and not the resource managers. Therefore, if a 
> request comes to a RB for multiple resources across multiple domains, 
> the complexity of the transaction problem will greatly increase if 
> each of the domain's RBs had an independent phase commit and then 
> follow that with an overall phase commit for all the resources across 
> all required domains. In contrast if only one RB was responsible for 
> the phase commit for all the requested resources (across all domains) 
> will simplify the transaction problem. Also, it is assumed that an  
> RB's access to a xRM in its domain has no particular advantage that is 
> not reflected in the policy of the resources (which will be advertised 
> by the xRM).
>
>
>
> C) Thank you very much for sharing your document; it is very informative.
>
> I am not sure I addressed all your concerns.... look forward to 
> hearing from you.
>
> Gigi
>
> --------------------------------------------
>
> Gigi Karmous-Edwards
> Principal Scientist
> Advanced Technology Group
> http://www.mcnc.org
> MCNC RTP, NC, USA
> +1 919-248 -4121
> gigi@xxxxxxxx
> --------------------------------------------
>
>
>
> Inder Monga wrote:
>
> > Dear Gigi and All,
> >
> > I was not present at the last GLIF meeting and plan to remedy that going
> > forward. I apologize for maybe bringing up the same issues again, but
> > these are my initial reactions in looking at the slides:
> >
> > A) I am surprised to see such a deep Grid flavor to the interfaces. I do
> > understand Grids are an important application of the GLIF network, but
> > can't GLIF define generic interfaces that can be used by non-grid
> > applications, management platforms, automated scripts? To choose this
> > path because OGF as a likely standardization body is not the right
> > reason. The defined generic interfaces need to fit into the "grid"
> > resource management model.
> >
> > B) In examining the multi-domain proposal, it looks like the RB from one
> > domain can request access to resources directly from the specific RM of
> > the next domain without notifying the RB of the other domain? This model
> > does not appeal to me. I am concerned about the case when resources 
> > are required across "n"
> > domains (say),  RBi (where i belongs to N) needs to access and request
> > resouces from xRMj where x = Network, Compute, Storage, Instrument and j
> > = 1 .. n, {n <=N} ? In this case, the RB needs to have knowledge of and
> > have access to (through firewalls) to all those RMs.
> >
> > In the multi-domain model we have demonstrated (detailed document
> > attached) that having each domain manager manage the resources within
> > its own domain makes the best architecture. With that model you have the
> > advantage of having only ONE multi-domain resource request entry point
> > (and corresponding AAA policies).
> >
> > I look forward to discussions on the mailing list.
> >
> > Thanks,
> > Inder
> >
> >
> > -----Original Message-----
> > From: owner-tech@xxxxxxx [mailto:owner-tech@xxxxxxx] On Behalf Of Gigi
> > Karmous-Edwards
> > Sent: Tuesday, April 17, 2007 4:18 PM
> > To: controlplane@xxxxxxx; GLIF-tech
> > Subject: [GLIF tech] Network Control Architecture
> >
> > Dear All,
> >
> > At the last GLIF control plane meeting in Minneapolis (meeting minutes
> > will be sent tomorrow to the list) we had several discussions on
> > interoperability between the different networks. We drew a diagram on
> > the white board with input from the participants. The outcome was an
> > action item on me to send out a high level functional diagram on the
> > framework for interoperability (sorry for the delay). We expanded the
> > notion of network resource in the control plane working group to include
> > other resources as well, such as compute, storage, instruments, etc.
> >
> > Enclosed are three very high level slides discussing the framework and
> > the high level functional components included  in a "Resource Broker 
> > " and a "Network Resource Manager". Several of you in the meeting had
> > comments on the interfaces we need to standardize. I propose we start
> > with the "Grid Network Interface"  GNI, first.
> >
> > We also agreed to work with both the GLIF community and standard bodies
> > like OGF to develop these interfaces. I look forward to your comments.
> >
> > Kind regards,
> > Gigi
> >
> > --
> > --------------------------------------------
> >
> > Gigi Karmous-Edwards
> > Principal Scientist
> > Advanced Technology Group
> > http://www.mcnc.org
> > MCNC
> > RTP, NC, USA
> > +1 919-248 -4121
> > gigi@xxxxxxxx
> > --------------------------------------------
> >
> >  


--
Bram Peeters
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