[j-nsp] Drawbacks when using QFX5100 and EX4300 in mixed VCF mode

[Pavel Lunin]

19.08.2014 19:51, Sebastian Wiesinger wrote:
> -----------------------------------------------------------------------
> Hardware Requirements for a Virtual Chassis Fabric
>
> A VCF can contain up to four devices configured as spines, and up to
> twenty total devices.
>
> All spine devices must be QFX5100 devices. We recommend optimizing the
> performance of your VCF by also configuring QFX5100 devices as your
> leaf devices. A non-mixed VCF has the highest port density and feature
> support for a VCF. Nevertheless, you can configure any combination of
> QFX5100, QFX3600, QFX3500, or EX4300 devices into leaf devices within
> your VCF.
> -----------------------------------------------------------------------
>
> Any idea what they are talking about? What drawbacks does a mixed VCF
> have in practice?
>
> One thing seems to be that you lose the ability to have output filters
> on interfaces but that's all I know.
>

I guess, there is a lot of marketing here. Of course, many features are
scaled down to the so-called "least-common denominator", as guys have
already mentioned above. But this is quite not surprising and doesn't
mean you must use a more featured product everywhere just because it's
more featured.

What about QFX3500, AFAIK, there's just no point to use them at all as
from the price/performance/features perspective QFX5100 is just better
except maybe some corner-cases (which I am not aware of). Using QFX3600
as leafs when spines are QFX5100 is non-reasonable from the pure
performance PoV as QFX3600 is a 40GE switch and QFX5100 is 10GE. What
about EX4300—of course any vendor would say you better buy 10GE switches
instead of 1GE just because 10GE switches have much more performance.
And this is totally correct, isn't it? ;)