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

[Kurt Bales]

Hello Sebastian,

When using a mixed mode VC, most of the features and scale drop back to
"Lowest Common Denominator". Eg the device with the smallest MAC size sets
the size for all members etc.

Here is a list of features compared for QFX Virtual Chassis Fabric:
https://www.juniper.net/techpubs/en_US/junos13.2/topics/reference/general/ex-qfx-series-software-features-overview-vcf.html

Also be aware that a VCF will not support PoE even if the member 4300 has
them.

Regards,

Kurt Bales
@networkjanitor JNCIE-ENT #368


On Tue, Aug 19, 2014 at 8:51 AM, Sebastian Wiesinger <
juniper-nsp at ml.karotte.org> wrote:

> 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
>
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