Solved: Re: MPLS over GRE across Carrier MPLS

mdasher79 · ‎02-27-2019

We're looking to extend our MPLS network across AT&T's MPLS network to a remote site. Is it possible to use GRE tunnels to achieve this? The Cisco document below specifically says MPLS over GRE across non-MPLS networks.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/mp_l3_vpns/configuration/xe-3s/mp-l3-vpns-xe-3s-book/mp-vpn-gre.html

Sergey Lisitsin · ‎02-27-2019

mdasher79,

That shouldn't be a problem The main thing to bare in mind though is you might need to lower your MTU to accommodate multiple additional headers. Other than that it should work fine. I have seen MPLS working without a glitch on GRE tunnel interfaces. I see no reason why these tunnels wouldn't be able to run on top of another MPLS network.

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Sergey Lisitsin · ‎02-27-2019

mdasher79,

That shouldn't be a problem The main thing to bare in mind though is you might need to lower your MTU to accommodate multiple additional headers. Other than that it should work fine. I have seen MPLS working without a glitch on GRE tunnel interfaces. I see no reason why these tunnels wouldn't be able to run on top of another MPLS network.

mdasher79 · ‎02-28-2019

Awesome, thank you for the quick response.