Hi Giles,
>
> The draft has a major limitation (no support for interconnecting routers,
> but only for interconnecting hosts),
What routers are you talking about ?
Common DC topology is as follows:
| |
VM - compute_node - | IP Fabric |
VM - compute_node - | Transport only |
Gateway - | + |
Storage Cluster - | Only when needed |
Appliance Cluster - | PE function |
| |
This draft only provides additional flexibility of connecting VMs together.
It does not mandate that entire tenant VPN must use concept of virtual
subnet as it is 100% compliant with current L3VPN RFC - it's an add-on not
substitute.
Of course one may say that I can use L3VPN or L2VPN no need for something
in the middle - fair point. But in the same time this is different from
prohibiting one to inject some host routes and do proxy arp for pair of VMs
which like to talk on the same subnet but happen to be sitting on different
compute nodes.
And while some vendors do fight hard against overlays for tenant
virtualization and would rather see all smartness of the networks in TOR I
am afraid that this ship has already left the harbor .... In the above VMs
are virtualized in the compute's node kernel eliminating any need for big
fat and expensive PEs acting as TOR.
Those can be just plain ODMs or OCP blades with pure IPv4 and/or IPv6
transport support running BGP 1/1 or 2/1 or IGP if one prefers it.
Cheers,
R.
