Werner Almesberger wrote:
[...]
> > 3.1, page 6, list.
> > Why is (N,N) excluded ? What if I have two sites X and Y, each with
> > a primary access link, and a backup link, and I want to describe
> > the network service between the two sites ? Excluding (N,N) seems to
> > require at least a justification.
> >
> > [Y: well, it is ok to indicate it, however, the semantics should then
> > also be mentioned. does the flow id and traffic enveloppe that is
> > described apply to any of the ingress points ? if so, than the service
> > that is described can be decomposed in n* (1,N), and would be a short
> > notation for this. we'll mention it in the next release.]
>
> I was mainly thinking of a service like this: company X has two sites
> A and B. ISP gives some assurances on traffic from A to B. Each site
> is connected via two links/routers to the network of the ISP. The ISP
> does not wish to reveal its internal structure in the contract with X
> (e.g. simply because they're changing things every month anyway).
>
> In this scenario, I don't think there's a natural mapping into
> independent (1,N) SLS. Of course, one could introduce inter-SLS
> dependencies ... :-(
If you map it into 2 independent (1,N) SLS, you will loose the
multiplexing effect between those two links. Is this example an
important one? I currently think it is not, because site A may figure
out on what link what amount of traffic is sent.
[...]
> > [Y: negotiation and definition of the SLSses seem to me to be pretty
> > tied together, although this is certainly not obvious from this version
> > of hte draft, agreed. ]
>
> Agreed in the sense that the negotiation has to use something that
> can be expressed in the language used for SLS'. But I think the SLS
> for the invoked service can be narrower while still being useful.
> Negotiation and such can then go to a different document ... (this
> has also the advantage that work on a specification for invoked
> SLS', which seem to be better understood at the moment, would not be
> slowed by any haggling over negotiation issues.)
I donīt aggree with Yves comment. negotiation and definition are only
losly copled. Many different negotiation scenarios are possible, with
the same definition. The simplest one is a Yes/no to an SLS request. For
more complex ones it needs to be specifed what parameters are
negotiatable, what is the range, is a price involved (ask, offer,bid)
etc.
Therefore, the negotiation needs to be at least in a separate document,
and it is probably too early to bring this up in a draft (nevertheless
it should be included into the charter of the WG.
>
> > [Y: i don't personally like the word bandwidth brokers, since different
> > people think about different things when bandwidth brokers are
> > mentioned. It is a given that services can be offered over diffserv
> > capable networks, and somehow these services should be described at the
> > edges of the network. Today this is highly static, and uses a form of
> > fax-signalling. We just want to have an automated infrastructure for
> > this...
>
> Exactly ;-)
>
What about "service broker".
> > [Y: I understand your doubts. let us try in the framework to give some
> > good reasons why SLS negotiation should be mentioned along with the SLS
> > formal formats.]
>
> Again, I'm convinced that a separate document is a better place for
> negotiation issues. They're close enough that this should be done in
> the same working group, though, IMHO.
I agree with Werner.
Marcus
>
> Cheers, Werner
>
> --
> _________________________________________________________________________
> / Werner Almesberger, ICA, EPFL, CH Werner.Almesberger@epfl.ch /
> /_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_____________________/
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