IWAN Routing Question

[aarumuganainar]

Hi All ,

I had a brain storming session with my colleague and we could not figure out the design question.

         IWAN HUB  DC

              |                |

              |                |

           MPLS       INTERNET------Remote Site 1

|                 |

|                 |

Remote Site 2

Remote site2 is connected only to Internet via Single circuit. . While site 2 is connected via both MPLS and Internet . Network is designed following standard IWAN design. i.e Separate DMVPN Cloud for MPLS and separate one for Internet .

Any to Any application eg : Lync has been set as Primarily via MPLS and if MPLS goes down it will go through internet.

Now when traffic going Remote site 2 to Remote site 1 . How will it go ? Will it be.

a) Remote Site 2 ----MPLS DMVPN ----DC ----INTERNET DMVPN---REMOTE SITE 1 ( This is because Remote site 2 thinks best path is MPLS )

b) Remote Site 2 ----INTERNET DMVPN----REMOTE SITE 1   ( Because .... I am not sure . Can some one explain :-) )

Could some explain what will be behavior in this case . I wanted to simulate this in the lab . But felt very lazy and hence wanted to ask the experts on this forumn .

Thanks very much in advance.

Arun

[pwwiddicombe]

That depends on the configuration in a whole lot of places.  Basically, do hub and DC share routing tables via a routing protocol, or have a number of static routes in place?  I presume the default route for both sites will be via the Internet connection.

This would depend on your WAN connection configuration, and probably can be influenced on the MPLS provider's setup.

[aarumuganainar]

Hi ,

This is IWAN  . I am planning to run BGP both MPLS-DMPVN Tunnel and also Internet DMVPN Tunnel  . .

In such a case, Remote site 1 will only learn the route from Hub site . But when traffic starts ...NHRP will point the route directly to Remote Site 2 . Hence Remote Site 1 will talk to Remote Site 2 directly via Internet DMVPN Tunnel. I have no issues with that.

However return traffic is bit worrying . If I set up the HUB following the IWAN guidelines , will remote site 2 learn the site 1 routes via MPLS DMPVPN Tunnel as well?  If so,will this not result in asymmetric routing.

Thanks and Regard

Arun