LAN Routing at Border Router at Hub, Branch in IWAN

[uzair.baig]

Hi,

I have a question regarding LAN routing in IWAN design with multiple Border routers at Hub and Branch.

I have 4 routers at Hub site, two router for MPLS (MPLSRtr1 & MPLSrtr2) and two routers for INET. There is L3 WAN Aggregation switch connecting all branch routers.

PFRv3 does intelligent path routing, but how do my WAN aggregation switch know that it should forward my critical application traffic to MPLS Rtr1. How do I route traffic to the correct border router?

Thanks, 

Uzair 

[cj.johnson3cigna]

To truly include your switch in the PFRv3 intelligent paths you'd have to join it to the same RFv3 domain as the hub routers. You could do something like creating a GRE tunnel between the MPLS & IWAN hub routers so PFRv3 can choose that for traffic you want to go to MPLSRtr1.

[Vasilii Mikhailovskii · Accepted solution]

Hello.

Your switch will participate in IGP and forward traffic to any of the BRs.

If a BR thinks (per MC decision), that a packet should be forwarded through another BR - it would send the packet to another BR using auto-tunnel (mGRE automatically created by PFR).

PS: please note, that branch PFR-enabled devices should be connected on the same subnet (otherwise PFR won't work on spoke BR device).

PS2: PFRv3 is not supported on switches.

[uzair.baig]

Thanks Vasilii, Yes we observed that routing decisions will be updated by MC to BR's then to WAN Switch.

On Branch site, we have created a gre tunnel between two Border routers.

[Vasilii Mikhailovskii]

Hello.

Even though GRE on branch is a known workaround of the limitation (to have both BRs on connectd subnet) it may introduce another issue once LAN interface on branch MC goes down.

[uzair.baig]

We have free ports on Router, Do you suggest connect router BR1 & BR2 back to back and enable eigrp neigbhorship between them.

Thanks

[Vasilii Mikhailovskii]

Hello.

For branch BR1 and BR2 - yes - connect routers back to back, configure a sub-interface and run IGP.

PS: this is recommended per CVD.

[Bhosle]

I am facing issue on similar Scenario, created sub-interface on Border Hub at DC for MPLS and INET connectivity back to back to Branch router. Generated traffic from Branch to DC.

facing one issue Traffic not pass on Tunnel which in created on sub-interface at DC. observation is the traffic pass on physical interface instead of Tunnel. 

anybody know solution over this problem...