The MPLS WG Archive

["Thomas D. Nadeau" <tnadeau@cisco.com>]

>Here is what I am still missing -
> From L1, I may get mplsOutSegmentIfIndex(L1), which is the interface index
>of L2, as you suggested.  Let's call this index i2.  Now the problem
>is how to get the L2 entry in mplsTunnelTable in TE MIB, by using i2.
>Look up the interface table does not help since this table only contains
>the LSP name of L2, but not the mplsTunnelIndex.  It seems to me that
>unless we scan the entire mplsTunnelTable and compare each mplsTunnelIfIndex
>with i2, there is no way to "directly" access the entry of L2 - this
>is what I was trying to avoid.

         I think that if you follow the convention that the heads use
tunnelInstance = 0, that you can prune your search down quite a bit.
If the tunnelTable is implemented correctly, your searches should be
fairly quick.

>I hope this is not true. Otherwise it seems to be an unfortunate
>consequence of the current MIB structure.

         Unfortunately, putting in a back pointer for every application
that uses the TFIB would have been quite complicated for
implementations.

         --Tom



>Thanks,
>Fang
>
>-----Original Message-----
>From: owner-mpls@UU.NET [mailto:owner-mpls@UU.NET]On Behalf Of Adrian
>Farrel
>Sent: Sunday, July 21, 2002 11:38 AM
>To: Fang Hao
>Cc: 'mpls@uu.net'
>Subject: Re: Question on MIB info for LSP tunneling
>
>
>Hi Fang,
>
>L1 is tunneled through L2.
>
>L2 is installed in the TE MIB with an ifindex using mplsTunnelIsIf and
>mplsTunnelIfIndex.  This means that it can be found within the
>implementation as
>an interface and available bandwidth can be examined just as though it was a
>physical interface.
>
>L1 shows in the LSR MIB with an outsegment that contains
>mplsOutSegmentIfIndex.
>This is the outgoing interface for L1 and is not the physical interface - it
>is
>the interface index of L2.
>
>So, from L1 you can get to L2.
>
>Adrian
>
>----- Original Message -----
>From: "Fang Hao" <fangh@research.bell-labs.com>
>To: "Adrian Farrel" <afarrel@movaz.com>
>Cc: <mpls@uu.net>
>Sent: Friday, July 19, 2002 2:44 PM
>Subject: RE: Question on MIB info for LSP tunneling
>
>
> > Adrian,
> >
> > Thanks for your reply. But I am still missing something -
> > the tunnel creation part is fine, but when I need to
> > access information about L2 (the LSP tunnel), I have a problem.
> > What I would need is: given LSP L1 (i.e., knowing its
> > mplsTunnelIndex), I need to find out which tunnel it is
> > going through, how much bandwidth is left on this tunnel L2,
> > what is the ingress/egress LSR id, etc.  For those info
> > I would probably need the mplsTunnelIndex for L2.
> >
> > If I am not misunderstanding the MIBs, this mplsTunnelIndex
> > (of L2) does not appear in either interface table or
> > out segment table. - any comments?
> >
> > Thanks,
> > Fang



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