Which recommendations for GRE tunnel overlay over SDWAN viptela system (ipsec underlay)?

[boythanhdat_2012]

Hi guys,

We have 1 SDWAN system as below diagram:

LAN1---Core 1 -------- cEdge1 ----transport sdwan----cEdge2-----Core2---LAN2

With:

- Cedge 1 have ipsec tunnel to cEdge2 by default of sdwan.

- Core 1 have gre tunnel with Core 2.

Actually, we tested: Gre tunnel of Core1-Core2 is up and we can ping between LAN1 and LAN2. But LAN1 can't access service of LAN2.

I checked in cEdge1 and cEdge2 with ipsec tunnel mtu 1441 and tcp-mss 1361 (automaticlly setup by sdwan system).

Any suggestions for this case?

Thanks all guys!

[boythanhdat_2012 · Accepted solution]

Yesterday, I changed mtu and tcp mss in gre tunnel as below:

Interface tunnel (GRE)
ip mtu 1400
ip tcp adjust-mss 1360

And the service is ok now.