On Feb 11, 2014:9:22 AM, at 9:22 AM, Robert Raszuk <[email protected]> wrote:
> Giles,
>
>
> > 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
>
> And that is reasonable discussion to have here rather then argue that BGP
> does not scale without providing pain points or that routers behind VM need
> to talk L2 to other routers behind VM (the latter is in fact possible via
> overlay over overlay today anyway if someone would desire so).
This is indeed the discussion we want to have here. I don't think Giles
or I were claiming BGP doesn't scale; again, its a matter of whether or not you
would want to send /32s around as prescribed.
--Tom
> You may be of opinion that current EVPN or PBB EVPN solve the problem. I
> agree they solve the problem, but the price is much higher - new development
> and new protocol extensions are needed to support it. Operating one more
> protocol is not free too.
>
> Here we just have a informational draft illustrating much cheaper option to
> allow hosts talk on the same subnet cross overlay boundary. I do see this as
> interesting tool to some of VMs communication requirements.
>
>
> > 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 ;)
>
> You are more then welcome ;-)
>
> r.
>
>
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