Say you have three separate layer 2 domains (Availability Zone 1, 2, and 3) with VLANs 0, 10, 20, and 30 in use on them. You have linux nodes in each domain tagging all packets, i.g. eth0 = VLAN 0, bond0 (eth1, eth2), and bond0.10, bond0.20, and bond0.30. The nodes in the three domains share the same IP address subnets, i.g. VLAN 0 = 10.0.0.0/24, VLAN 10 = 10.0.1.0/24, VLAN 20 = 10.0.2.0/24, and VLAN 30 = 10.0.3.0/24.
1) How do you send packets to one of the nodes in the other domain? Since they all share common subnets, how will Linux know to route packets through a gateway interface to the other domains? Furthermore, the ARP table for one domain won't have MAC addresses for IPs in the other domain... they won't share broadcast domains. So they can't talk to each other right?
2) If you are able to send packets to the nodes in the other domains, do the VLAN headers get stripped when they cross the gateway?
If I understand things correctly, we need VPLS to connect the three separate layer 2 domains into a single broadcast domain. Yes? Are there other ways, i.g. GRE or MPLS tunnels?, to join these into a single broadcast domain?
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