SDWAN networking TLOC-EXT configuration consultation

[haininghuang3185]

Site A and site B have two Cedge routers, using TLOC-EXT networking mode. The TLOC-EXT interface addresses of the Cedge routers at both sites use 2.2.18.1, 2.2.18.2, 2.2.18.5, 2.2.18.6. Will there be any problems?

[haininghuang3185]

We use show sdwan bfd session on both sites and see that the tunnels are all up.

[MHM Cisco World]

It 1.1.18.x not 2.2.18.x

The router not accept two interface in same subnet.

You  need to change one subnet  in each cedge pair.

And since you use internet you need to NATing.

MHM

[haininghuang3185]

Yes,it 1.1.18.X

SiteA
The Cedge01 sub-interface is configured as follows:
G0/0/1.1 ip address 1.1.18.1 255.255.255.252
G0/0/1.2 ip address 1.1.18.6 255.255.255.252
The Cedge02 sub-interface is configured as follows:
G0/0/1.1 ip address 1.1.18.2 255.255.255.252
G0/0/1.2 ip address 1.1.18.5 255.255.255.252

SiteB
The Cedge01 sub-interface is configured as follows:
G0/0/1.1 ip address 1.1.18.1 255.255.255.252
G0/0/1.2 ip address 1.1.18.6 255.255.255.252
The Cedge02 sub-interface is configured as follows:
G0/0/1.1 ip address 1.1.18.2 255.255.255.252
G0/0/1.2 ip address 1.1.18.5 255.255.255.252

In addition, the two routers of SiteA and SiteB are configured with NAT on the Internet interface.
With the above configuration, will there be any problem in establishing a BFD session between the Cedge routers of SiteA and SiteB?

[MHM Cisco World]

You use 255.255.255.252 so IP is acceptable.

And with NAT the config is perfect.

There is no issue at all.

And it easy you can check tloc it must up if it down then bfd is not reachable between cedge's.

MHM

[haininghuang3185]

The new topology map is updated as follows

[MHM Cisco World · Accepted solution]

In order to be sure that if we use same private subnet between two cedge in two site ( which I dont see any problems since site id is different and there is NAT)

Do tloc extensions use same subnet in both site (only one to check) then check below 

The dtls to controller must be UP in both site dor cedge use tloc extensions

cEdge-01L#show sdwan control connections

https://www.cisco.com/c/en/us/support/docs/routers/sd-wan/220333-configure-layer-3-tloc-extension.html

MHM