Re: draft-eng-nalawade-ospf-tunnel-cap-00.txt

[Rahul Aggarwal <[e-mail]>]

Hi Sandy,

On Mon, 10 Nov 2003, Sandy Eng wrote:

> Rahul,
>
> Rahul Aggarwal wrote:
> > Following up on this thread, I have the following concerns with this
> > document:
> >
> > 1. Tunnels are used both intra and inter domains. Thus tunnel
> > capabilities have to be propagated across domains as well. Hence IGP is
> > imho not appropriate for this application.
> >
> > 2. Tunnel capabilities are not used by core routeres.
>
> As we are announcing specific router capabilities, it therefore infers
> that only certain routers in the network are capable of some specific
> capabilities. If all routers in a network have the same capability,
> there is then no need for specific announcement.
>

The tunnel encapsulations are needed by the PE routers and are advertised
by the PE routers. Different PE routers can advertise different tunnel
capabailities. However P routers do not require this information.

rahul

> Thanks,
> Sandy
>
>
>
> >
> > 3. There are existing documents that specify the use of BGP for this:
> > draft-raggarwa-ppvpn-tunnel-encap-sig-01.txt
> > draft-nalawade-kapoor-tunnel-safi-01.txt
> >
> > Hence imho OSPF WG should not take on this work.
> >
> > Thanks,
> > rahul
> >
> > On Tue, 28 Oct 2003, Robert Raszuk wrote:
> >
> >
> >>Acee,
> >>
> >>
> >>>     My biggest fear would be that if this draft is accepted it
> >>>     would only be the first of a torrent of auto-configuration
> >>>     drafts.
> >>
> >>Second one not first ;). Notice this one submitted a while back:
> >>draft-raszuk-ospf-bgp-peer-discovery-00.txt
> >>
> >> >     1. Should OSPF be used for tunnel auto-configuration?
> >>
> >>I think in general this requires a study on a case by case basis. Most
> >>important factors which should be taken into consideration are:
> >>
> >>*A* How frequently the information advertised changed - is it static
> >>configuration or dynamic in nature which triggers reflooding ?
> >>
> >>*B* Is the application which the uses delivered information limited to
> >>IGP domain or crosses domains ?
> >>
> >>*C* What is the amount of information to be flooded (keeping in mind
> >>that majority of P routers - those in the core - will never use it.
> >>
> >>*D* What are the alternatives available & _deployed_ today to deliver
> >>the same information to it's users
> >>
> >>*E* How often area wide flooding will be sufficient versus domain wide.
> >>
> >>Coming back to draft-eng-nalawade-ospf-tunnel-cap-00.txt I see the
> >>following:
> >>
> >>Reg A: Info is essentially static except the L2TPv3 cookie rollover
> >>intervals which if implementation permits could be changing periodically
> >>
> >>Reg B: I think that in any application of tunnels we can't limit the
> >>scope of use to one IGP domain. There can be a lot of customers who may
> >>never need to go over a domain (which this draft is targeting though).
> >>
> >>Reg C: Minimal (comparing to TE at least :):).
> >>
> >>Reg D: It is worth noting that there is a few drafts in IDR describing
> >>the ideas for the same information distribution
> >>
> >>Reg E: Looking at the most common OSPF topologies I would say that most
> >>tunnels will be build between edge PEs and those in a lot of cases are
> >>located in it's own POP areas. Not to say that there are no customers
> >>who keep most of their PEs on the edges of area 0.
> >>
> >>Rgs,
> >>R.
> >>
> >
>