The MPLS-OPS Archive

[Kumar S <ps2kumar@yahoo.com>]

Hi Padmini,

Per interface label space is usefull if you are going to implement Label controlled ATM, where in VCI and VPI are labels. Since VCI and VPI are local to an ATM interface and the same VCI and VPI values can be used to creates Virtual circuits over multiple ATM interfaces.

 

Regards

Shailender

"M.V. Padmini" <padmini@genie.iitd.ernet.in> wrote:

> Well, the debate may not end so soon after all!!
>
> First of all, when i meant unique labels - i meant it for a complete LSR
> and among all LSRs not confinig to the ingress.
>
> The idea i had in mind was - keep all edges of the graph unique - ur done.
> But this will lead to exhausting the labels very soon. If u look at it
> carefully, you may need to keep the labels unique only between two
> adjacent sets of input and output labels. Never the less, by putting in
> the label space, you are trying to build a heirarchical structure of
> labels.
>
> Does that make sense or am i off track?
>
> > Hi,
> >
> > I feel label-space will be important even if u assign unique labels to
> > FECs at the ingress LSR. Imagine thie scenario wherein,
> >
> > FECs A, B, C are assigned labels (1,2,3) uniquely by the ingress...
> >
> > At the nex!
>  t LSR,
>  these labels are swapped (1,2,3)->(2,2,3), then in
> > this case the information provided by the label-space would be
> > important for swapping at the next LSR. (althou i am not really sure
> > whether the swapping (1,2,3)->(2,2,3) is really valid !!)
> >
> > --Sundeep.
> >
> >
> > On Fri, 17 Sep 2004, M.V. Padmini wrote:
> >
> >> Hi sudeep,
> >>
> >> Well, we are talking of a static routing scenario here. When we
> >> alreadly know the LSR, where where is the need to use the label space
> >> info? (well pardon me since i have still not read the doc.
> >> completely!). Since the labels on the LSRs are unique, there is no
> >> question of messing up. Well, as far as the simple routing is
> >> concerned, unique label for every FEC should work fine. May be its
> >> required in some other cases i.e. Tunnel etc. Am not sure. The other
> >> reason could be not to run o!
>  ut of
>  labels!!
> >>
> >> - Padmini
> >>
> >>
> >>> Hi Padmini,
> >>> We are also in the process of creating a MPLS test-bed in IITB. I
> >>> guess
> >>> the notion of lablespace is to identify the interface that the labels
> >>> come from (as you have rightly said), but this concept is useful in
> >>> processing at the hop on the basis of interfaces that it come from,
> >>> rather than trying and identifying each and individual labels and
> >>> then processing. Labelspaces can make some processing fast.
> >>>
> >>> As far as a small test-bed is considered, it doesn't make a
> >>> difference
> >>> to
> >>> use or not to use labelspaces.
> >>>
> >>> I have successfully traversed ping packets using MPLS on my
> >>> test-bed.
> >>> But
> >>> ssh and other application packets seem!
>   not to
>  work as of now. Lets
> >>> see. Efforts are on :)
> >>>
> >>> ciao,
> >>> Sudeep
> >>>
> >>>
> >>> On Fri, 17 Sep 2004, M.V. Padmini wrote:
> >>>
> >>>>
> >>>> We are in the process of implementing a Test bed for MPLS using
> >>>> linux boxes. Having gone through the mplsadm literature, they seem
> >>>> to be using two parameters (label, labelspace) to be associated with
> >>>> each Interface for an FEC. The labelspace is supposed to identify
> >>>> the interface (from which it came) where the labels could be same
> >>>> (labels coming from different interfaces).
> >>>>
> >>>> Is there a need to do this? If you enforce the uniqueness of the
> >>>> label wrt to a FEC, dont u think that there is no requirement for a
> >>>> labelspace. Am i missing
>  something?
> >>>>
> >>>> Thanks in advance.
> >>>>
> >>>>
> >>>>> Abhishek Mittal wrote:
> >>>>>> 6> Fix up the MTU size
> >>>>>
> >>>>> After upgrading to a newer IOS on the Catalyst yesterday, I just
> >>>>> added MPLS IP to the 12k router again --- works fine now (with 1512
> >>>>> as MTU on all used interfaces) ...
> >>>>>
> >>>>> -gg
> >>>>>
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> >>
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> >> ERNET Project
> >> Dept. of Computer Science and Engineering
> >!
>  > IIT
>  Delhi
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> >>
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> >
> > --
> > Sundeep.
> >
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>
> ____________________________________________
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>
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>
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