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

[Sebastian Wiesinger]

Hello,

Juniper supports mixing QFX5100 and EX4300 in a Virtual Chassis Fabric
mixed mode but they talk about some vague performance and/or impact
when doing so:

-----------------------------------------------------------------------
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.

Regards

Sebastian

-- 
GPG Key: 0x93A0B9CE (F4F6 B1A3 866B 26E9 450A  9D82 58A2 D94A 93A0 B9CE)
'Are you Death?' ... IT'S THE SCYTHE, ISN'T IT? PEOPLE ALWAYS NOTICE THE SCYTHE.
            -- Terry Pratchett, The Fifth Elephant