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Re: Linux implementation of MPLS

  • From: "M.V. Padmini" <padmini@genie.iitd.ernet.in>
  • Date: Tue, 21 Sep 2004 07:01:41 +0530 (IST)
  • Cc: <ps2kumar@yahoo.com>, <singh0de@ee.iitb.ac.in>, <sudeepg@cse.iitb.ac.in>, <mpls-ops@mplsrc.com>
  • Importance: Normal
  • Resent-Date: Mon, 20 Sep 2004 22:00:32 -0400

The mail seems to have bounced back.  Sending it again.

> Well this is exactly what i wanted to know!!!  It looked like there was
> something more to it and not just to support the rerouting ability.
> This may make it easier but its extra effort and not all that needed or
> should i say there is a simpler workaround.
>
> Never the less, thanks - not the i know of ATM!!
>
> - Padmini
>> 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 next 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 out 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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>>>>>>
>>>>>>
>>>>>> ____________________________________________
>>>>>> ERNET Project
>>>>>> Dept. of Computer Science and Engineering
>>>>>> IIT Delhi
>>>>>> New Delhi - 110 016
>>>>>>
>>>>>> Phone: +(91)-11-2659 6009
>>>>>>
>>>>>>
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>>>>>
>>>>> --
>>>>>
>>>>> When a great leader's work is done, people say "we did it
>>>>> ourselves". -Tao
>>>>>
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>>>>
>>>>
>>>> ____________________________________________
>>>> ERNET Project
>>>> Dept. of Computer Science and Engineering
>>>> IIT Delhi
>>>> New Delhi - 110 016
>>>>
>>>> Phone: +(91)-11-2659 6009
>>>>
>>>>
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>>>
>>> --
>>> Sundeep.
>>>
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>>
>>
>> ____________________________________________
>> ERNET Project
>> Dept. of Computer Science and Engineering
>> IIT Delhi
>> New Delhi - 110 016
>>
>> Phone: +(91)-11-2659 6009
>>
>>
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>
>
> ____________________________________________
> ERNET Project
> Dept. of Computer Science and Engineering
> IIT Delhi
> New Delhi - 110 016
>
> Phone: +(91)-11-2659 6009


____________________________________________
ERNET Project
Dept. of Computer Science and Engineering
IIT Delhi
New Delhi - 110 016

Phone: +(91)-11-2659 6009


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