RE: MPLS over GRE

Hi Routing Freak,

See inline:

> Why OTV has this in built MPLS over GRE logic.

The goal is Ethernet over IP, so Ethernet has to encapsulate in something.
EoMPLS is already a standard so no need to rewrite the book. It's the same
logic as AToM or VPLS. Likewise MPLS over GRE is already defined, so if you
want to do L2 over L3 then why not do EoMPLSoGRE. This makes it transport
agnostic, i.e. any IPv4 transport is sufficient. It seems convoluted but at
the transport speeds its designed for the overhead is negligible.

> With L2 , u cant do multipath and also u cant move ur virtual machines
seamlessly

Yes you can do multipath, with the most basic example being 802.3ad Port
Channels (EtherChannel). More advanced multipathing would be vPC
(Multi-Chassis EtherChannel), FabricPath (L2 IS-IS Routing), or TRILL when
released.

> Can u give me some more examples for this Seamless Mobility with the same
MAC Address.

http://www.cisco.com/en/US/docs/solutions/Enterprise/Data_Center/DCI/4.0/EMC/
EMC_2.html

> With normal L2, u cant do multipathing, u encapsulate L2 with L3 and do all
sorts of magic what L3 gives u . but TRILL is also same as MPLS label
switching or like OTV. Is there any logic behind this MPLS over GRE ? I dont
see any logic for this ?

TRILL DCI is still in proposal
(http://tools.ietf.org/html/draft-aldrin-trill-data-center-interconnect-00).
OTV DCI works today and is implemented.

H8Rs gonna H8, but GRE is the ultimate band-aid of networking ;)

Brian McGahan, CCIE #8593 (R&S/SP/Security)
bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>

Internetwork Expert, Inc.
http://www.INE.com

From: Routing Freak [mailto:routingfreak_at_gmail.com]
Sent: Tuesday, August 28, 2012 8:28 PM
To: Bob Sinclair
Cc: Brian McGahan; Cisco certification
Subject: Re: MPLS over GRE

Hi Brian

Why OTV has this in built MPLS over GRE logic.
With L2 , u cant do multipath and also u cant move ur virtual machines
seamlessly
Can u give me some more examples for this Seamless Mobility with the same MAC
Address.

With normal L2, u cant do multipathing, u encapsulate L2 with L3 and do all
sorts of magic what L3 gives u .
but TRILL is also same as MPLS label switching or like OTV. Is there any logic
behind this MPLS over GRE ?

I dont see any logic for this ?

On Fri, Aug 24, 2012 at 3:41 AM, Bob Sinclair
<bob_at_bobsinclair.net<mailto:bob_at_bobsinclair.net>> wrote:
Hi Brian,

Just read your Blog post on this.
(http://blog.ine.com/2012/08/17/otv-decoded-a-fancy-gre-tunnel/)
 Great Work! Thanks for sharing the captures.

-Bob

-----Original Message-----
From: nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>
[mailto:nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>] On Behalf Of
Brian McGahan
Sent: Thursday, August 23, 2012 2:21 PM
To: Craig Miller; Cisco certification; CCIE KID
Subject: RE: MPLS over GRE

Overlay Transport Virtualization (OTV) also uses MPLS over GRE:
http://ine.co/otv

Brian McGahan, CCIE #8593 (R&S/SP/Security)
bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>

Internetwork Expert, Inc.
http://www.INE.com

-----Original Message-----
From: nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>
[mailto:nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>] On Behalf Of
Craig Miller
Sent: Thursday, August 23, 2012 11:17 AM
To: Cisco certification; CCIE KID
Subject: Re: MPLS over GRE

I've never had to use it before, but I've considered it for some instances,
and ended up going with other solutions. Where it would be useful, is
connecting your MPLS network, across a non-MPLS network, or someone elses
MPLS network.

Bridging two PE routers, a P to PE router, two P routers. From a non-service
provider perspective, if you have a need to run your own Enterprise MPLS
network internally, you might have several remote sites that are connected
to your network via a carrier MPLS, or maybe the remote site has just a
normal internet pop. In both of those situations, probably more obvious to
the remote site that has a normal internet pop, you can use a GRE solution,
DMVPN etc, to establish a peer to peer session with your own infrastructure,
from there, you can bridge your MPLS network over your carriers network, no
matter what their infrastructure consist of.

This could also be used in situations such as company mergers and such to
maintain continuity while doing the migration.

Hope that helps,
Craig

--- On Thu, 8/23/12, CCIE KID
<eliteccie_at_gmail.com<mailto:eliteccie_at_gmail.com>> wrote:

> From: CCIE KID <eliteccie_at_gmail.com<mailto:eliteccie_at_gmail.com>>
> Subject: MPLS over GRE
> To: "Cisco certification"
<ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>>
> Date: Thursday, August 23, 2012, 9:28 AM Hi all
>
> I was going through some GRE use cases and i found that MPLS runs over
> GRE.
> I cant visualize any proper use case logic for this MPLS over GRE. And
> that GRE is termed as soft GRE. Is there anyone who worked on MPLS
> over GRE implementation. Where it is used extensively and how it is
> been designed
>
> I can see that when SP is not offering MPLS services , then we can
> tunnel over MPLs switched packets from ISP to other ISP over GRE where
> the latter ISP support only IP and not MPLS . Is there any other
> scenario or else any special use case for MPLS over GRE.
>
> Thanks in advance,
>
> --
> With Warmest Regards,
>
> CCIE KID
> CCIE#29992 (Security)
>
>
> Blogs and organic groups at http://www.ccie.net
>
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Received on Wed Aug 29 2012 - 00:20:58 ART