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

Hi Vishal,

At 01:26 PM 4/26/2004 -0700, Vishal Sharma wrote:
Hi Fabio, JL, et al

I think Fabio may have a good idea here. It provides the flexibility
of having info. about all affinities, with the scalability of advertizing
only limited information.

This problem has been investigated for a while and there many constraints that cannot be aggregated in a simple/efficient manner, leading to the constraint of having to flood a un-reasonable amount of TE-related info to make it useful enough to compute an optimal (shortest) path with some good chance of set up success.

Cheers

JP.

Perhaps we can explore a bit where there might be issues, and refine
this initial solution to get something that we believe is appropriate.

-Vishal

> -----Original Message-----
> From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org]On
> Behalf Of ricciato
> Sent: Monday, April 26, 2004 9:59 AM
> To: LE ROUX Jean-Louis FTRD/DAC/LAN
> Cc: adrian@olddog.co.uk; ccamp@ops.ietf.org
> Subject: Re: RE : RE : Proposed strategy for Inter-area/AS
>
>
> 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.
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >
> >
> >
> >
>