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Re: MPLS VPNs or not?

  • From: Christian Kuhtz
  • Date: Tue Aug 07 10:35:24 2001

On Tue, Aug 07, 2001 at 03:14:02PM +0100, Randy Bush wrote:
> > Take a look at the [email protected] archives for a rather exhaustive and
> > exhausting discussion of this very subject, or provide facts as to what
> > specifically doesn't scale.
> to paraphrase vijay, if dealing with one rib is a major discussion in the
> operator and ietf communities, how many thousands of them do you think a
> prudent operator wants to deal with in 2547?

I think you're blowing this completely out of proportion like it has happened
on [email protected] before.

A PE carries only the routes needed at a specific PE depending on the VPNs
present at a specific PE.  The routes aren't kept in a seperate rib, what
happens is that a meta rib is created which indexes all rib entries based on
their origin.  Sounds a lot more complicated but it is in essence something
like this:

They're called VPNv4 routes, consisting of IPv4 routes and the index (with 
128, 129, 130 being the index..  ).  It's still just one rib. Provided all
those RD's are present at the same PE.

So, how many thousands of suitable MPLS VPN customers do you have for this
to amount to much?  

Again, there has been an exhaustive discussion of this on [email protected] many
moons ago, and for you specifically to rehash this issue in another forum 
again is rather curious to me.

You couldn't win the argument in IETF MPLS, and now it's being dragged to

> did you notice all those extra *e routers with 2547?  do you wonder why
> router vendors push 2547?

If the shoe fits, why not?

MPLS VPNs solve a very specific set of problems.  If you don't like because it 
doesn't fit your operational model, don't use it.  But this sort of generic
bashing and FUD leads nowhere.

Christian Kuhtz <[email protected]> -wk, <[email protected]> -hm
Sr. Architect, Engineering & Architecture,, Atlanta, GA, U.S.
"I speak for myself only."