Sdwan works only with area 0

[dijix1990]

I found out that sdwan cEdge works only with ospf area 0, but it strange, maybe someone knows why?

[balaji.bandi]

sdwan cEdge works only with ospf area 0

Can we have more context before we can confirm or agree your statement?

SD-WAN requires the underlay control/data plane to be reachable to work with the controller.

[dijix1990]

I tried to configure ospf on service side with area 5, but ospf process doesn't install prefixes to rib on my cEdge, I changed cEdge to non-sdwan router and ospf works correctly. After it I changed area to 0 and ospf installed prefixes to rib

My config very simple

C9300x where I have area 0 and area 4-5 for different devices, area 4 for asa connection, area 5 for sdwan connection

From guide

Configure Basic OSPF

To configure basic OSPF, select Basic Configuration and then configure the following parameters. All these parameters are optional. For OSPF to function, you must configure area 0, as described below.

[Kanan Huseynli]

Hi,

that is correct. OSPF enabled SD-WAN router considers itselfs as connected to "MPLS Super backbone". So, edge router behaves like ABR (one "leg" is on area 0 i.e super backbone). Hence, if you choose non-backbone area in service side but there are other ABRs in that area (like your 9300 switch), then type3 LSA from that neighbor will be ignored. This action is default OSPF action where one ABR ignores other ABR's type3 LSA over non-backbone area (area 5 in your case).

So, you have to "stretch" area0 till that 9300 which means between 9300 and sdwan router you can only have area0 if you want to get type3 LSA from 9300.

Non-zero area may work only if there is no other ABR in service-side.