[j-nsp] qfabric 1536k mac address?

Eugeniu Patrascu eugen at imacandi.net
Thu Jan 2 13:27:54 EST 2014


On Thu, Jan 2, 2014 at 8:10 PM, giovanni rana <superburriccu at hotmail.com>wrote:

> I do, but how big is my DC is not relevant, like being flat or non flat
> does not matter...Since the data sheet clearly says 1.536.000 Mac addresses
> are supported, I need to understand if we are talking of unique Mac
> addresses or that's a number made by using mac-vlan pairs (and so
> Overlapping MACs) as described in "The QFabric Architecture - Juniper
> Networks" PDF.
> Let's make it simple, qfx3500 has a 128k Mac table. I've attached some big
> esxi clusters on my qfabric and now I got 129k VMs each one with unique Mac
> address, will I face any problem?
>
>
Of course you will face a problem as one single switch can only handle 128k
MAC addresses.

The whole QFabric system can handle 1.5M MAC addresses but only if you have
a full buildout of leaves and spines, not just a single switch.

And just for fun, if you do the math, you won't be able to cram anywhere
near 128K ESXi VMs on QFX3500 switch as you have usable 48 10GbE ports
(assuming the maximum).

You can have a maximum 512 VMs per host or 4000 VMs per 32 host cluster
under vSphere 5.5.
This gives you 2 clusters available (1 of 32 hosts and another of 16
hosts). This 8000 VMs maximum with two VMware clusters. Even if you would
go with 48 independent ESXi hosts and each fully loaded with 512 VMs you
would get a maximum of 24576 MAC addresses from them + 48 from the hosts.

I think you need to rethink your scenario or ask what you really want to
ask.

Eugeniu


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