[j-nsp] qfabric 1536k mac address?

[giovanni rana]

Ahahah that was just an example ;)) And of course i can put another standard L2 switch between the hosts and the qfx3500 which aggregates all the hosts and goes to the qfx3500 with a single 10ge port, if I don't mind about oversubscr. ratio, but this is not about design, it's about understanding how and where those 1536k Mac addressees are indexed, or it is just marketing?
please take the  "The QFabric Architecture - Juniper Networks" document, go to page 21, figure 17. i got 2 nodes now, node A and node B. i got also 131072 VMs with unique MAC addresses in my single /15 subnet because i like it big, VMs' are equally splitted between the nodeA and nodeB, so 65536 VMs are attached on nodeA and 65536 on nodeB. Let's forget clusters, ESXi limitations and so on. 
the table on Qfabric nodeB is made like in the figure 17:MAC,VLAN; NEXTHOPmac1,VLAN1; QFabric nodeA (remote VM attached on nodeA)mac2,VLAN1; QFabric nodeAmac3,VLAN1; QFabric nodeA ..mac65536,VLAN1;QFabric nodeAmac65537,VLAN1; port P (locally attached VM)mac65538,VLAN1; port P mac65539,VLAN1; port P...mac128000,VLAN1;port Pwhat's next? the qfx3500 CAM is exhausted now, how can i handle mac128001....mac131072?
adding nodes or changing the number of VLAN's does not make me understand how can i overcome the 128K limitation, or better, i'm missing how this "information hiding" principle works. from the document, it seems that all the entries from mac1 to mac65536 which are all pointing to nodeA can be aggregated/merged all together, because they can point to a remote unique node instead to a local port, but this doesn't mean they take less entries (or less "space") in the mac address table compared to normal entries. 
thanks! 








Date: Thu, 2 Jan 2014 20:27:54 +0200
Subject: Re: [j-nsp] qfabric 1536k mac address?
From: eugen at imacandi.net
To: superburriccu at hotmail.com
CC: bdale at comlinx.com.au; juniper-nsp at puck.nether.net

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