Hi Robert, On 11 Feb 2014, at 13:16, Robert Raszuk <[email protected]> wrote:
> Hi Giles, > > The draft has a major limitation (no support for interconnecting routers, but > only for interconnecting hosts), > > What routers are you talking about ? any routers you might want on the subnet other than the default gateways. For example a customer might want to put a virtual network behind a pair of VMs. In a L2 overlay (or in any other normal subnet) those could communicate directly with any other routers on the subnet. > 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. but as you yourself have said - if there's no need for it then why add it? There are many different ways those two VMs can communicate already. I'm not sure we need to invent another (though sure, it's fun to invent new stuff). > 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. thanks for putting words in my mouth Robert. I appreciate it ;) Giles > 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. >
