[c-nsp] MPLS VPN over mGRE

[David Prall]

Sounds like you are using BGP Signaled MPLS VPN over mGRE which uses a
Route-Map on the neighbor relationship to provide the tunnel information.
http://www.cisco.com/en/US/docs/ios-xml/ios/interface/configuration/xe-3s/ir
-mpls-vpnomgre-xe.html

David

--
http://dcp.dcptech.com


> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> bounces at puck.nether.net] On Behalf Of John Neiberger
> Sent: Wednesday, January 30, 2013 10:55 AM
> To: Adam Vitkovsky
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] MPLS VPN over mGRE
> 
> The type of MPLS VPN over mGRE that we're using doesn't use a
> preconfigured
> tunnel interface or NHRP. As I understand it, the peers share
> tunnel-related information in vpnv4 updates using a SAFI of 64. This tells
> the other peers that those prefixes are related to the mgre tunnel and
that
> signals the receiving router to set up an adjacency over the multipoint
> tunnel, but I'm not quite sure how it does this. I don't understand what
> element of the config tells the router to use SAFI 64 in the vpnv4 updates
> instead of just treating them like regular L3VPN vpnv4 updates. It's kind
> of confusing. There seems to be a lot of magic happening under the hood
> here that I'm missing.
> 
> John
> 
> 
> On Wed, Jan 30, 2013 at 1:15 AM, Adam Vitkovsky
> <adam.vitkovsky at swan.sk>wrote:
> 
> > Wow they really shrunk it down to three commands plus the route-map,
> now
> > that's something.
> >
> > > or is there some other mechanism that triggers tunnel endpoint
> discovery?
> > I believe since it's called mGRE it has to be NHRP taking care of
> > everything
> > in the background.
> > Does the loopback IP has to be allocated from a common range that has to
> be
> > shared among the PEs?
> >
> > I thought it's done via standard mGRE tunnels:
> >
> > interface Tunnel0
> > ip address 192.168.1.1 255.255.255.0
> > ip mtu 1440
> > ip nhrp authentication cisco123
> > ip nhrp map multicast dynamic
> > ip nhrp network-id 1
> > tunnel source FastEthernet0/0
> > tunnel mode gre multipoint
> > tunnel key 0
> > ip router isis 1
> >
> > -maybe "mpls ip" cmd. wouldn't work with mGRE Tunnel Int.
> >
> >
> > adam
> >
> >
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