The MPLS-OPS Archive[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] Re: Linux implementation of MPLS
Adding one more bit... > Lets end the debate (hopefully!!) :) > Taking this from google: > > "Labelspaces define the scope of forwarding rules. If two interfaces of > the same MPLS router belong to the same labelspace, then they apply the > same > set of forwarding rules to MPLS packets. For example, if interfaces ``2'' > and ``4'' are part of the same labelspace, then two packets with the same > label arriving one on interface ``2'' and the other on interface ``4'' > will follow the same forwarding rule. On the other hand, if multiple > interfaces do not belong to the same labelspace then the incoming MPLS > packets follow different forwarding rules." unless both rules dictate that packet be forwarded to the same interface. This is possible and consistent with RFC 3031. You have two options: a) global label spaces across interfaces with ONE single forwarding rule for a pair of (primary, backup) LSP. b) different label spaces but TWO forwarding rules for each LSP: one for primary and one for backup. I believe that either of these options is fine. If you use (b), I don't think you lose much, if any, on performance. If you use (a), you know your constraints. > This might be of help for understanding !!! > Now, Faisal you seem to be right, different labelspaces would > interfere with re-routing. > > cheers, > Sudeep > > > > On Sat, 18 Sep 2004, Sudeep Goyal wrote: > >> >>> But I think global single label space is good as in case of MPLS fast >>> reroute and penultimate hop label popping, the MP can swap labels >>> without knowing that the traffic is coming from bypass tunnel or from >>> the primary tunnel (different interfaces). Recall fast reroute use >>> label stacking. >> >> I am not sure, but wondering if different labelspaces would interfere >> with >> the re-routing. >> >>> On the other hand per interface label space is good as it increases >>> the number of labels that can be used by a router. >> >> Makes sense! >> >> >>> Once again as well as I know both exist in theory, side by side and >>> ideally should be supported by any implementation. >>> Check if you can specify labelspace to null and it work ?? >> >> In the implentation, if labelspace is set to -1 it stops working else >> when >> the global labelspace is set to 0 (or anything), it works without any >> fuss. >> Haven't tried about null labelspace yet. >> >> >> >> >> >>> Thanks >>> Faisal Aslam >>> >>> On Fri, 17 Sep 2004 21:28:37 +0530 (IST), M.V. Padmini >>> <padmini@genie.iitd.ernet.in> 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 >>>>> >>>>> ------- >>>>> The MPLS-OPS Mailing List >>>>> Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml >>>>> Archive: http://www.mplsrc.com/mpls-ops_archive.shtml >>>> >>>> ____________________________________________ >>>> ERNET Project >>>> Dept. of Computer Science and Engineering >>>> IIT Delhi >>>> New Delhi - 110 016 >>>> >>>> Phone: +(91)-11-2659 6009 >>>> >>>> ------- >>>> The MPLS-OPS Mailing List >>>> Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml >>>> Archive: http://www.mplsrc.com/mpls-ops_archive.shtml >>>> >>> >>> ------- >>> The MPLS-OPS Mailing List >>> Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml >>> Archive: http://www.mplsrc.com/mpls-ops_archive.shtml >>> >> >> > > -- > > When a great leader's work is done, people say "we did it ourselves". > -Tao > > ------- > The MPLS-OPS Mailing List > Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml > Archive: http://www.mplsrc.com/mpls-ops_archive.shtml > ------- The MPLS-OPS Mailing List Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml Archive: http://www.mplsrc.com/mpls-ops_archive.shtml
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