The MPLS WG Archive

[Art King <art@frost-king.com>]

Mark,

I've seen a number of configurations where ISP's have merged and have broken
AS's because pieces of the original backbone have been removed in order to
reduce duplicate costs on same route and no one has time/skill to go back
and rebuild/renumber the original network(s). This required BGP to be
tunneled via GRE between dis-contiguous chunks of the same AS. For this
provider topology, tunneling MPLS traffic and MP-BGP over same GRE tunnel
achieves some level of transparency. It's kind of a corner case.

Thanks,

Art
----- Original Message -----
From: "Mark Duffy" <mduffy@quarrytech.com>
To: "Art King" <art@frost-king.com>
Cc: <mpls@UU.NET>
Sent: Thursday, August 15, 2002 4:01 PM
Subject: Re: Encapsulating MPLS in IP or GRE


> Hi Art, are you suggesting that there is something about the MPLS VPN case
> in particular that favors mpls-in-gre over mpls-in-ip?  If so would you
> explain that?
>
> Thanks, Mark
>
>
> At 01:32 PM 8/15/02 -0700, Art King wrote:
> >Connecting MPLS VPN PE's over non-MPLS core in a Carrier is a
> >good example case for GRE usage.
> >
> >----- Original Message -----
> >From: "Eric Rosen" <erosen@cisco.com>
> >To: "Shahram Davari" <Shahram_Davari@pmc-sierra.com>
> >Cc: <mpls@UU.NET>; "Loa Andersson" <loa.andersson@utfors.se>; "George
> >Swallow" <swallow@cisco.com>
> >Sent: Wednesday, August 14, 2002 11:27 AM
> >Subject: Re: Encapsulating MPLS in IP or GRE
> >
> >
> >>
> >> In some  cases you  might already have  a GRE  tunnel through which
you
> >are
> >> supporting a routing adjacency.  It should be possible to send MPLS
> >packets,
> >> as  well  as  IP  packets,  through  such  tunnels,  and  this
requires
> >an
> >> MPLS-in-GRE encapsulation.
> >>
> >> There are also  other cases in which GRE tunnels (as  opposed to IP
> >tunnels)
> >> are  commonly used,  and you  should be  able to  send MPLS  packets
> >through
> >> them.
> >>
> >