We are planning to connect a pair of QFX 5200 (QFX is a WAN device where ISP connections terminates) and a pair Fortinet 3800. Fortinet further connects to my LAN core switch.
For redundancy purpose we are planning to connect QFX and Fortinet in criss-cross so the each QFX will connect to each Fortinet. Now, Fortinet that runs in HA mode (active-active), should be able to talk to the same gateway IP in QFX.
Each QFX has L3 separation no L2 link between them. So I cannot run VRRP on them.
In this case, how do I provide redundant out going gateway in QFX. In each QFX I can have an aggregated interface and assign a IP to it. But I cannot have two WAN outgoing gateway IPs in the Fortinet without vrrp. In Fortinet HA mode, it is just one single config for both units. It internally syncs the config to other firewall.