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New Member

Multiple Frame Relay Switches using GRE Tunnel for Cisco Lab

This is the answer to my own question that I found with help from the author of the below two blog write ups that I was using together to create a two switch backbone that was connected via GRE over two gig ports to service a fully meshed frame relay network (works great if you have two smaller routers with room for only two T1's each, which gives you 4 connected frame relay routers for your lab).  The problem that I didn't understand was the DLCI mapping portion.

Basic router layout:

R1 <- Serial -> FRSW1 <- GRE via Gig -> FRSW2 <- Serial -> R2

The fix, or missing part:

One router uses normal DLCI route statements such as:

frame-relay route 105 interface Tunnel0 501 (this side does the translations for both directions of traffic)

The other side uses a different DLCI route statement such as:

frame-relay route 501 interface Tunnel0 501  (this pushes it through the tunnel to the other side as an untranslated DLCI)

R1 -> FRSW1 is one half, and R2 to FRSW2 through to FRSW1's tunnel is the other half.

Hope this helps someone out

New Member

Multiple Frame Relay Switches using GRE Tunnel for Cisco Lab

Thank you so much for your tip!!

I found Mike's great post and spent quite some time scratching my head on what could be wrong!! 

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