Re: [mpls-linux-general] Re: [MPLS-Linux] RSVP-TE (was: New mailing list)

[Ramanjaneyulu Y T <yt...@cs...>]

On Thu, 30 Nov 2000, James R. Leu wrote:

> On Thu, Nov 30, 2000 at 10:52:30PM +0530, Ramanjaneyulu Y T wrote:
> > Hi James ,
> >   This is really good job. I appreciate your efforts. Are u doing any work
> > related to RSVP-TE ?.
> 
> Not as part of MPLS for Linux yet.  I have done some work with RSVP-TE 
> for my employeer.  Because of that fact I can't be the one to start working
> on RSVP-TE for Linux, but if some else "starts" it I'll make it part
> of MPLS for Linux ;-)
> 
> >   I have one queastion related to LSP hierarchy. How LSRs distinguish
> > label stack ?. How remote LSR knows it label from other side , if
> > hierarchy is permited ?. 
> 
> First, I guess we need to get a few things sorted out, before I can
> answer that question.
> 
> Are you refering to using RSVP-TE to create hierarchy, or are you refering
> to how hierarchy works in general.

I am referring to create hierarcht.


> 
> If your refering to using RSVP-TE to create hierarchy, are you confused
> about how to signal it or how (after it has been signaled) the ILM, NHLFE
> are setup to actually do hierarchy?


If I  remember right , hierarchy is achieved with help of PUSH and FWD
operations in ILM and NHLFE . 


 Last night i refered some drafts and RSVP-TE supports Label stacks in
LABEL object . My queastion is how LSR knows , how many labels pop ( i.e
take off from) from LABEL object. Let me explain my probelm clealry.

  

   LER1             LER21        LER22 ....   LER 2
  |-----|          |-----| . .  | ----|       |-----|  
  |     |----------|     |------|     |-------|     | 
  |-----|          |-----|      |-----|       |-----|





       LER21 and LER22 is one MPLS domain. Suppose LER1 want to
establish LSP to LER2. If one allows Hierarchy setting , it should make
use of LSP between LER21 and LER22. when LER2 responded with RESV message, 
How this RESV message is treated in MPLS domain ( beteen LSR21 and LER22)
?. IN normal case each LSR gets one new label for previous hop and it
binds this with next hop label , which he got from next hop. , then it
propagets to previous hop.

  If we r setting hierarchial lSPs , only resource reseravtion done at
each LSR when RESV messagae comes. No label storing abd getting new label
at each core LSRs in MPLS domain 1 , except at edge routers. So how core
LSrs will ignore to store label info ? .

  I think I am clear now.    





> 
> Sorry to answer you question with questions.
> 
> Jim
> 
> BTW "First post" :-)
>