Hi. I am having some trouble understanding this fundamental part of SD-WAN:
For example, if a branch site has 2 x vEdge routers. One connected to Internet, the other connected to MPLS - with TLOC extensions in place.
On the service side there is a Check Point Firewall Cluster (running OSPF), and between this and the vEdge routers is a Layer 2 switch.
The vEdge router connected to MPLS will learn its BGP routes from the service provider MPLS router.
It will then redistribute these into OSPF which is running on the FW cluster. The redistribution happens bi-directionally.
I am confused by trying to work out how the OSPF neighbour adjacencies are formed. The FW cluster is Active/Standby so in effect it is only one neighbour advertised to the routers using the Virtual IP address.
Would the FW establish two separate neighbour adjacencies with each vEdge router? Although one vEdge is just connected to the ISP, would using a TLOC extension mean that an adjacency is formed with that vEdge? If so, then the FW would use ECMP and share the traffic load equally between each vEdge router.
I am not quite understanding what determines which router traffic is sent from the FW to the vEdges when there is more than one vEdge. I understand that policies will determine what happens with the traffic when it leaves the vEdges.
