Re: RE : RE : Proposed strategy for Inter-area/AS

[ricciato <ricciato@coritel.it>]

Dear JL,

you´re right.

Just a quick proposal.
In an attempt to limit the number of virtual link advertised,
would it make sense to advertise only K virtual links, where K={number 
of colors}, and for each of them  (say j) advertise the maximum 
bandwdith over all links that have color j into their admin_group ?

For example, in your example (with Path 4 added)

Path 1: bw 100M admin group {green;blue}
Path 2: bw 50M admin group {red; blue}
Path 3: bw 5M admin group {red;green}
Path 4: bw 50M admin group {red}

One should advertise 
Virtual Link 1: bw 100M admin group {green} --->max(100M,5M)
Virtual Link 2: bw 50M admin group {red} --->max(50M,5M,50M)
Virtual Link 3: bw 100M admin group {gblue} --->max(100M,50M)


Assuming that the number of colors << number of possible links, this approach might cap the amount of advertisement.

But I´m not sure it works ... 

ciao
fabio

LE ROUX Jean-Louis FTRD/DAC/LAN wrote:

> Hi Fabio,
>
> Advertising only a subset would improve scalability, but
> this would not be enough to correclty select the best path.
>
> Let's assume that there are three paths from a given ABR X to a given destination D
> Path 1: bw 100M admin group {green;blue}
> Path 2: bw 50M admin group {red; blue}
> Path 3: bw 5M admin group {red;green}
>
> and a TE-LSP L : Destination D, bw= 4M, affinity= exlude blue
>
> If you advertise only Path 1 and Path 2 as virtual links, ABR X will never be selected as next ABR for this TE-LSP, while path 3 is a feasible path.
>
> Regards
>
> JL 
>
>
>
>  
>
> > -----Message d'origine-----
> > De : owner-ccamp@ops.ietf.org 
> > [mailto:owner-ccamp@ops.ietf.org] De la part de ricciato
> > Envoyé : lundi 26 avril 2004 09:48
> > À : LE ROUX Jean-Louis FTRD/DAC/LAN
> > Cc : adrian@olddog.co.uk; ccamp@ops.ietf.org
> > Objet : Re: RE : Proposed strategy for Inter-area/AS
> >
> >
> > Hi JL,
> >
> > just a quick remark: would it make sense in this case to 
> > advertise only 
> > a selected subset of the N virtual links (say the two with 
> > most residual 
> > bw) ?
> >
> > ciao
> > fabio
> >
> > LE ROUX Jean-Louis FTRD/DAC/LAN wrote:
> >
> >    
> >
> > > Let's assume that there are N distinct paths from ABR A to a 
> > > destination X, each with a distinct bandwidth and distinct 
> > >      
> > admin-group 
> >    
> >
> > > (a path admin group being expressed as a logical AND of the 
> > >      
> > link admin 
> >    
> >
> > > groups along the path) How can you summarize such topology ? 
> > >      
> > Actually 
> >    
> >
> > > you need to advertise N virtual links, each with a distinct 
> > >      
> > admin-group 
> >    
> >
> > > and available bandwidth.
> > >
> > >
> > >
> > >
> > >
> > >
> > >      
> >
> >    
>
>
>