The MPLS-OPS Archive

[Puddinhead Wilson <puddinghead_wilson007@yahoo.co.uk>]

Sylvia,

Perhaps You could look at the way the "reachability"
itself is advertised as a way to space switch? 
It could have a capability to switch for large amount
of reachability via a certain node.

Similar to the example you previously mentioned about
certain end points not being reachable via a
particular path.

-PW

--- Spice Sylvia <falsesylvia@yahoo.co.uk> wrote:
> Hi,
> 
> 
> > 
> > If you will only ever have one LSP across your
> core,
> > I agree that hierarchy doesn't save you much
> > (although the technology boundaries may still make
> > it desirable so that (e.g.) you odn't have to look
> > at packets on a lambda router.
> > 
> > The saving comes when you have bulk parallel LSPs
> > across the core. That ain't stitching.
> > 
> > (NB. Some people like to see stitching as a
> special
> > case of 1:1 hierarchy without label stacking. I
> > wouldn't like to comment :-)
> 
> Exactly, if I dont have something "changing" what is
> wrong with statically provisioning once and for all.
> 
> > 
> > Your figure is perhpas a rather simplistic
> network.
> > Let us insert a whole network cloud between N2 and
> > N3 so that the hierarchical LSP runs
> > N2,n1,n2,n3,n4,N3.
> > N2 will allocate a single lambda to reach N3.
> > This lambda will carry all of the traffic from N1
> to
> > N4 and from N5 to N6.
> > The traffic at N3 is easily discriminated so that
> it
> > can be sent to N4 or N6. But within the core
> network
> > (at the nx nodes) only one lambda needs to be
> > switched.
> 
> Ok so we are building a "hierarchy of lambdas". At
> the
> same time, how is this different from the statically
> provisioned thin pipes of colored water pour into a
> thick pipe analogy? As long as the thick pipe does
> not
> have demuxing capabilities of each individual/or
> some
> subs of thin pipes, it does nothing but carry all
> water from here to there.
> 
> Similarly is there any resource that needs to be
> "signalled" in this? I an understand signalling Call
> Parameters as they are dynamic and unique per call,
> but what basically confuses me is the aspect of
> "signalling" when a resource cannot do any dynamic
> allocation. (even in terms of lambdas/space matrix
> switching, we are not looking at moving links
> dynamically across ports, are we?)
> 
> > There is no difference in effect between a
> manually
> > provisioned LSP and an LSP provisioned by the
> > control plane. The purpose of a control plane is
> > well discussed elsewhere, but includes dynamic
> > utilisation of resources (so that the core can
> have
> > resources that are used for different purposes at
> > different times), dynamic provisioning (to
> simplify
> > the management plane interactions), and
> > responsiveness to network utilisation and faults
> (to
> > allow repair and recovery as well as
> optimization).
> > 
> But a node with switching an no TE capabilities can
> never fall in the category of being able to perform
> "dynamic utilization of resources".
> 
> 
> > Now it may be that you asking (subtly) how and
> when
> > the FA LSP is provisioned. Is it triggered when
> the
> > first LSP tries to cross the core? Is it
> > pre-provisioned through management planning? Are
> new
> > FA LSPs added automatically when load increases?
> 
> Agreed, now how do I add "lambdas" automatically?
> 
> Either we have a "waveguide/channel" or we dont. The
> purpose of signalling here beats me.
> 
> 
> > 
> 
> > 
> > Yes!
> > You can see the core network as a giant (virtual)
> > cross connect. This is one of the models used to
> > provide layer 1 VPN services.
> > 
> Yes, but only if I assume it is a pipe with "no
> participation in TE from the edge's perspective".
> 
> Just like the router over TDM overlay. As far as the
> end routers go, and from the signalling plane
> perspective, the 2 links are as good as one "fat
> conduit" between 2 nodes, if we assume that the TDM
> network cannot participate in signalling.
> 
> 
> I am still no grasping what is the element "which
> needs to be programmed by the signal" when a node
> has
> no TE properties.
> -brgds
> Sylvia
> 
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